Re: [Talk-GB] building shapes from OS Street View, with code
From: Steve Doerr steve.do...@blueyonder.co.uk Sent: Sunday, May 30, 2010 3:08 PM Looking forward to testing this, but having some problems with the prerequisites. I've installed this 'Python' thing (version 2.6) and the shapely library, but the NumPy install is failing with a message 'Python version 2.6 required, which was not found in the registry'. I'm guessing that it may be because NumPy is a 32-bit build (I downloaded it from http://downloads.sourceforge.net/project/numpy/NumPy/1.4.1/numpy-1.4.1-win32-superpack-python2.6.exe?use_mirror=ovh) whereas Python is 64-bit. So, do I reinstall Python as 32-bit, or is there a 64-bit version of NumPy around? With Tim's help, I was able to locate and install 64-bit versions of everything. With an adapted version of the command given in the README file, I have been able to process the TQ67SW tile to produce a 4.75MB .osm file. I haven't loaded it into JOSM yet, but I'm looking forward to seeing the results. It took a little over 7 hours to run, by the way. -- Steve ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View, with code
Also fuzzer is a bugger to get working and I don't know how to edit the fuzzyselect.py to get it doing what I wanted (i.e. auto-tracing from OS StreetView), so this script should definitely help! On Fri, 2010-05-28 at 10:11 +0100, TimSC wrote: Hi mappers, Thanks for the comments on automatic tracing. I have finished an implementation and it is ready for testing. It runs really slowly (30 minutes a tile). Be careful if you try it and don't remove any existing OSM information (and try not to annoy other mappers). The OS open data license is also a concern, so keep the source tags where appropriate. Please limit yourself to areas you are prepared to manually check and fix. (The LWG are aware of this issue, but don't anticipate problems.) The python code is here (with a readme file): http://timsc.dev.openstreetmap.org/dev/mapseg0.1.tar.gz Let me know if there are any major bugs or possible improvements. I am not sure I can put in much time in the short term but I will fix any major problems. I will do a wiki page eventually for further updates. http://wiki.openstreetmap.org/wiki/Mapseg As Ed Avis suggested, I flag suspected errors during the conversion. I don't use the surrounding pixel colours but there are plenty of other heuristics that indicate problems. I assume all buildings have at least 4 sides which are orthogonal. Any non orthogonal buildings will be flagged for checking. I automatically add a source tag auto_os_street_view. This should be changed to a different source tag when it has been verified. I suggest source=os_street_view for verified buildings. The fuzzer plugin for JOSM is nicely integrated but it operates on the rectified tiles which have lower quality images. My approach uses the original opendata tiles. TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View, with code
For a final source tag (i.e. the verified buildings) shouldn't we be using source=OS_OpenData_StreetView as noted in the wiki: http://wiki.openstreetmap.org/wiki/Ordnance_Survey_Opendata#When_tracing_over_OS_StreetView --- On Fri, 28/5/10, Roy Jamison xtee...@googlemail.com wrote: From: Roy Jamison xtee...@googlemail.com Subject: Re: [Talk-GB] building shapes from OS Street View, with code To: TimSC mapp...@sheerman-chase.org.uk Cc: talk-gb@openstreetmap.org Date: Friday, 28 May, 2010, 10:29 Also fuzzer is a bugger to get working and I don't know how to edit the fuzzyselect.py to get it doing what I wanted (i.e. auto-tracing from OS StreetView), so this script should definitely help! On Fri, 2010-05-28 at 10:11 +0100, TimSC wrote: Hi mappers, Thanks for the comments on automatic tracing. I have finished an implementation and it is ready for testing. It runs really slowly (30 minutes a tile). Be careful if you try it and don't remove any existing OSM information (and try not to annoy other mappers). The OS open data license is also a concern, so keep the source tags where appropriate. Please limit yourself to areas you are prepared to manually check and fix. (The LWG are aware of this issue, but don't anticipate problems.) The python code is here (with a readme file): http://timsc.dev.openstreetmap.org/dev/mapseg0.1.tar.gz Let me know if there are any major bugs or possible improvements. I am not sure I can put in much time in the short term but I will fix any major problems. I will do a wiki page eventually for further updates. http://wiki.openstreetmap.org/wiki/Mapseg As Ed Avis suggested, I flag suspected errors during the conversion. I don't use the surrounding pixel colours but there are plenty of other heuristics that indicate problems. I assume all buildings have at least 4 sides which are orthogonal. Any non orthogonal buildings will be flagged for checking. I automatically add a source tag auto_os_street_view. This should be changed to a different source tag when it has been verified. I suggest source=os_street_view for verified buildings. The fuzzer plugin for JOSM is nicely integrated but it operates on the rectified tiles which have lower quality images. My approach uses the original opendata tiles. TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View, with code
Potlatch's b option will place source=OS OpenData StreetView (note no underscores) if you have OS SV in the background. I use this as I prefer 1 keystroke to 20 or so. From: TimSC mapp...@sheerman-chase.org.uk To: talk-gb@openstreetmap.org Sent: Fri, 28 May, 2010 10:57:25 Subject: [Talk-GB] building shapes from OS Street View, with code Ah yes, the recommended tag is good. I didn't notice one had been chosen (but it is a bit long for my taste). So use source=OS_OpenData_StreetView for verified buildings. And I will probably change to source=Auto_OS_OpenData_StreetView for automatic tracing in the code. TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View, with code
...any reason why no underscores with Potlatch? --- On Fri, 28/5/10, Jerry Clough - OSM sk53_...@yahoo.co.uk wrote: From: Jerry Clough - OSM sk53_...@yahoo.co.uk Subject: Re: [Talk-GB] building shapes from OS Street View, with code To: talk-gb@openstreetmap.org Date: Friday, 28 May, 2010, 11:15 Potlatch's b option will place source=OS OpenData StreetView (note no underscores) if you have OS SV in the background. I use this as I prefer 1 keystroke to 20 or so. From: TimSC mapp...@sheerman-chase.org.uk To: talk-gb@openstreetmap.org Sent: Fri, 28 May, 2010 10:57:25 Subject: [Talk-GB] building shapes from OS Street View, with code Ah yes, the recommended tag is good. I didn't notice one had been chosen (but it is a bit long for my taste). So use source=OS_OpenData_StreetView for verified buildings. And I will probably change to source=Auto_OS_OpenData_StreetView for automatic tracing in the code. TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb -Inline Attachment Follows- ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View, with code
Ah yes, the recommended tag is good. I didn't notice one had been chosen (but it is a bit long for my taste). So use source=OS_OpenData_StreetView for verified buildings. A bit long yes, and probably not what Potlatch uses if you press 'b' when the Streetview background is selected (I see this has been covered in later posts - it uses the description for the selected background as shown in the dropdown list IIRC), but autocomplete in Potlatch and JOSM tend to pick it up once you've done one or two (though when tracing lots of buildings I tag the first manually in JOSM and then copy tags with Ctrl-Shift-V to all the rest). Oh, and I was using source:building=OS_OpenData_StreetView for the original outline, as whether I've then terraced that building into multiple properties and/or added house numbers, shop names, or whatever are all down to surveyed information, so I wanted to be clear. (Similarly if I've added a road from GPS trace but name from SV I add it as source:name). I'm not entirely happy where I've surveyed a traced building and changed it from building=yes to building=garages about not showing that garages is from survey, but wasn't sure how to handle that. Presumably any non-yes value must be from a survey (it is around here, at least - here being http://osm.org/go/0EHnCuAO ). Ed ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View, with code
Ask Richard F! From: Tim François sk1pp...@yahoo.co.uk To: talk-gb@openstreetmap.org; Jerry Clough - OSM sk53_...@yahoo.co.uk Sent: Fri, 28 May, 2010 11:20:10 Subject: Re: [Talk-GB] building shapes from OS Street View, with code ...any reason why no underscores with Potlatch? --- On Fri, 28/5/10, Jerry Clough - OSM sk53_...@yahoo.co.uk wrote: From: Jerry Clough - OSM sk53_...@yahoo.co.uk Subject: Re: [Talk-GB] building shapes from OS Street View, with code To: talk-gb@openstreetmap.org Date: Friday, 28 May, 2010, 11:15 Potlatch's b option will place source=OS OpenData StreetView (note no underscores) if you have OS SV in the background. I use this as I prefer 1 keystroke to 20 or so. From: TimSC mapp...@sheerman-chase.org.uk To: talk-gb@openstreetmap.org Sent: Fri, 28 May, 2010 10:57:25 Subject: [Talk-GB] building shapes from OS Street View, with code Ah yes, the recommended tag is good. I didn't notice one had been chosen (but it is a bit long for my taste). So use source=OS_OpenData_StreetView for verified buildings. And I will probably change to source=Auto_OS_OpenData_StreetView for automatic tracing in the code. TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb -Inline Attachment Follows- ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View, with code
...he scares me Only joking! I had come across a few of the non-underscored versions a few days ago, and was wondering why they were formatted like that. Now I know!! Also, today I learned you can do ctrl+shift+V to copy tags between ways/nodes - I've wasted large portions of my life doing this manually! Every day's a school day... *goes off to try and find a page with more neat time saving tricks...* --- On Fri, 28/5/10, Jerry Clough - OSM sk53_...@yahoo.co.uk wrote: From: Jerry Clough - OSM sk53_...@yahoo.co.uk Subject: Re: [Talk-GB] building shapes from OS Street View, with code To: talk-gb@openstreetmap.org Date: Friday, 28 May, 2010, 11:31 Ask Richard F! From: Tim François sk1pp...@yahoo.co.uk To: talk-gb@openstreetmap.org; Jerry Clough - OSM sk53_...@yahoo.co.uk Sent: Fri, 28 May, 2010 11:20:10 Subject: Re: [Talk-GB] building shapes from OS Street View, with code ...any reason why no underscores with Potlatch? --- On Fri, 28/5/10, Jerry Clough - OSM sk53_...@yahoo.co.uk wrote: From: Jerry Clough - OSM sk53_...@yahoo.co.uk Subject: Re: [Talk-GB] building shapes from OS Street View, with code To: talk-gb@openstreetmap.org Date: Friday, 28 May, 2010, 11:15 Potlatch's b option will place source=OS OpenData StreetView (note no underscores) if you have OS SV in the background. I use this as I prefer 1 keystroke to 20 or so. From: TimSC mapp...@sheerman-chase.org.uk To: talk-gb@openstreetmap.org Sent: Fri, 28 May, 2010 10:57:25 Subject: [Talk-GB] building shapes from OS Street View, with code Ah yes, the recommended tag is good. I didn't notice one had been chosen (but it is a bit long for my taste). So use source=OS_OpenData_StreetView for verified buildings. And I will probably change to source=Auto_OS_OpenData_StreetView for automatic tracing in the code. TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb -Inline Attachment Follows- ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb -Inline Attachment Follows- ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View, with code
Tim, In Potlatch you can also use 'r' or 'Shift-R' to repeat the tags from the last way you had selected. See [1]http://wiki.openstreetmap.org/wiki/Potlatch/Keyboard_shortcuts GrahamS On Fri, 28 May 2010 10:39 +, Tim François sk1pp...@yahoo.co.uk wrote: ...he scares me Only joking! I had come across a few of the non-underscored versions a few days ago, and was wondering why they were formatted like that. Now I know!! Also, today I learned you can do ctrl+shift+V to copy tags between ways/nodes - I've wasted large portions of my life doing this manually! Every day's a school day... *goes off to try and find a page with more neat time saving tricks...* References 1. http://wiki.openstreetmap.org/wiki/Potlatch/Keyboard_shortcuts ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View, with code
Thanks for that - I don't use Potlatch, but the amazing array of shortcuts for everything astounds me every time: some good work by the author! --- On Fri, 28/5/10, Graham Stewart gra...@dalmuti.net wrote: From: Graham Stewart gra...@dalmuti.net Subject: Re: [Talk-GB] building shapes from OS Street View, with code To: Tim François sk1pp...@yahoo.co.uk, OpenStreetMap TalkGB talk-gb@openstreetmap.org Date: Friday, 28 May, 2010, 11:54 Tim, In Potlatch you can also use 'r' or 'Shift-R' to repeat the tags from the last way you had selected. See http://wiki.openstreetmap.org/wiki/Potlatch/Keyboard_shortcuts GrahamS On Fri, 28 May 2010 10:39 +, Tim François sk1pp...@yahoo.co.uk wrote: ...he scares me Only joking! I had come across a few of the non-underscored versions a few days ago, and was wondering why they were formatted like that. Now I know!! Also, today I learned you can do ctrl+shift+V to copy tags between ways/nodes - I've wasted large portions of my life doing this manually! Every day's a school day... *goes off to try and find a page with more neat time saving tricks...* ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Tom Chance t...@... writes: On 24 May 2010 15:24, Gregory nomoregrapes at googlemail.com wrote: Harry has done some good blog posts about London's gaps in buildings. But this is an area with strong mapping activity. We can leave it to locals to trace buildings in the gaps with some memory or to hold off if they know people are surveying it this week. In cities towns with no buildings at all, it's better to leave these blank and when the mappers come they can work on it. I think that's a bit naieve.There are still lots and lots of noname roads in London, particularly in the poorer parts of outer London. Road names are really very easy to survey and add in.After all of TimSC's work there are large parts of London without landuse areas.Whilst Harry's mapping parties have done wonders for POIs in Central London, the rest of the city has very patchy coverage.Even cycle routes are incomplete and cycle parking coverage is very limited.Mapping buildings based on surveys for accuracy is laborious by comparison, and even after a year or more of experimentation by a few brave souls a tiny percentage of London has seen any activity.I'm inclined to support a mass import of automatically traced buildings with a noname layer equivalent, or a modification to noname, to aid verification and improvement by people such as myself who are interested in doing buildings properly.Best,Tom -- http://tom.acrewoods.net http://twitter.com/tom_chance ___ Talk-GB mailing list talk...@... http://lists.openstreetmap.org/listinfo/talk-gb I appreciate what TimSC has done and would like to see use made of it if someone can give a legal opinion that the licence is rock solid, but I do not see us as ready for a nationwide import yet; while there is no particular problem why buildings should not run ahead of addresses, other places where the community has to digest the results may come to light. Perhaps the answer is to convert the building outlines to .osm files at this stage. I would be interested in using this where I live. It is also worth making notes of where we do not want to import buildings from StreetView because it is out of date or there are better sources. -- Andrew ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Tue, May 25, 2010 at 06:24:25PM +0100, Roy Jamison wrote: I have tried using the JOSM plugin to trace buildings but can't get it to work, it keeps coming up with a problem with the child process. Is Same here: see http://josm.openstreetmap.de/ticket/5068 ael ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
TimSC mapp...@... writes: I have done a small test of automatically tracing buildings from OS Street View. http://osm.org/go/eurUp7x0Q- The biggest problem I can see is where roads or text labels obsure the buildings. Yes, in those cases you just have to guess where the building might go, usually by assuming it is rectangular. The OS Street View map simplifies many buildings to rectangles anyway. Can the code notice that the outside of the building is not the usual light-coloured background, and so either guess a plausible outline for the obscured bit, or flag the building for extra manual checking? I guess the fundamental question is, is this quicker than doing the whole thing manually? Undoubtedly, and also on the whole less error-prone. Once this gets going we can produce a 'buildings noname' map for people to go out and verify the position and street address of buildings. -- Ed Avis e...@waniasset.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On 24 May 2010 11:16, Ed Avis e...@waniasset.com wrote: Once this gets going we can produce a 'buildings noname' map for people to go out and verify the position and street address of buildings. I didn't think anyone was suggesting this be done on any kind of expansive area. It shouldn't be done beyond a mappers 'territory' or 'reach'. For example I am starting a process where I trace a few blocks of buildings, go out and map them (might be 2-4 trips worth) and then when I've edited/uploaded that area I begin tracing again. This helps people see that mapping is happening in the area, there is probably no point getting house numbers for the buildings because I may be out surveying them already, instead trace some more buildings. Example: http://osm.org/go/euuOoSiY With such a tool as is being described I could trace more buildings, but I would still restrict this to what I expect to survey in a month or two. (longer than that and I might have moved home and abandon mapping the area, or mapping tactic/direction might change) -- Gregory o...@livingwithdragons.com http://www.livingwithdragons.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Gregory nomoregra...@... writes: [trace buildings from OS] Once this gets going we can produce a 'buildings noname' map for people to go out and verify the position and street address of buildings. I didn't think anyone was suggesting this be done on any kind of expansive area. It shouldn't be done beyond a mappers 'territory' or 'reach'. When I first started mapping in OSM the London streets had been traced from Yahoo aerial photos but there were large unnamed areas, including the area where I lived. Immediately I could go out and start finding names without needing to know too much about tagging, how to draw shapes, or owning a GPS device. If the existing mappers had limited themselves to their own local areas, then faced with a blank canvas it would be more difficult for beginners to start mapping. Fundamentally, though, our goal is surely to get the best possible free map. Even in a town where no OSM contributor lives, the OS data makes a valuable contribution. The building shapes are simplified, to be sure, but generally superior in quality to those that have been traced from the fairly low-res Yahoo imagery. So by all means take care of your local area first, but we shouldn't lose sight of the broad goal of nationwide coverage. If we need to get more OSM contributors in unmapped parts of the country, one of the best ways to do that is to give them the best head start possible by 'armchair mapping'. -- Ed Avis e...@waniasset.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Robert Whittaker (OSM) wrote: My understanding is that the current terms from OS are incompatible with ODbL (in particular the part that allows produced works to be released to the public domain). This is a canard and I wish it would stop coming up. ODbL does _not_ say that Produced Works can be released entirely without restriction (US public domain). 4.3 is very clear that if you Publicly Use a Produced Work, You must include a notice associated with the Produced Work reasonably calculated to make any Person that uses, views, accesses, interacts with, or is otherwise exposed to the Produced Work aware that Content was obtained from the Database, Derivative Database, or the Database as part of a Collective Database, and that it is available under this License. OS OpenData is released under an attribution-only licence (compatible with CC-BY) and the terms of attribution are, in my entirely unqualified view, satisfied by ODbL 4.3. cheers Richard -- View this message in context: http://gis.638310.n2.nabble.com/building-shapes-from-OS-Street-View-tp5091506p5093953.html Sent from the Great Britain mailing list archive at Nabble.com. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
It appears the choice for buildings is a fight between OS maps, which are likely derived from high-resolution aerial photos but have been simplified, and the somewhat lower-resolution photo images available to OSM. It is not really possible to survey building shapes on the ground since GPS isn't precise enough, even if we had enough mappers to walk round the outside of every building. In London the Yahoo photos are adequate for tracing streets, but trying to get buildings from them is a bit ropey. Hence my feeling that the OS data is of higher quality, even though it's clearly a simplification of the real shape. But in other, less crowded parts of the country a semi-automated trace from aerial photos (using the Fuzzer JOSM plugin you mention) might be a better way. (Indeed, it might be fun to trace the whole country using both methods and then highlight differences between the two.) I still believe we could do *something* to get reasonably good building shapes into the map without waiting for the man-years needed to hand-survey them all. Even in an area which is not any mapper's particular 'territory'. The workflow might be to view the aerial photograph with the OS-traced building shapes on top, and then either press a button to import the whole area or select individual shapes. -- Ed Avis e...@waniasset.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On 24 May 2010 14:43, Richard Fairhurst rich...@systemed.net wrote: I don't know what the quality of StreetView is like in your area, but I would weep if someone were to blindly trace from StreetView in Charlbury without ever having visited it. The building outlines just aren't that great. Let's not lose sight of OSM's strengths in an enthusiasm to slurp as much free data as possible. If someone traces Hampton or Durham buildings with no intention of on-the-ground surveying then I too will -well I won't cry, but I'll say some angry words in the irc #osm channel. I'm getting annoyed enough at having to fix over-keen landuse. It's not about the accuracy of the imagery(aerial or OS) but about knowing the area, and finding out when a building might need splitting with a gap or when they no longer exist due to recent redevelopment. Harry has done some good blog posts about London's gaps in buildings. But this is an area with strong mapping activity. We can leave it to locals to trace buildings in the gaps with some memory or to hold off if they know people are surveying it this week. (Plug if your in the area, come to http://wiki.openstreetmap.org/wiki/London/Summer_2010_mapping_parties ). In cities towns with no buildings at all, it's better to leave these blank and when the mappers come they can work on it. I know I don't like armchair mappers (or rather I don't want to be one). There is a difference between tracing roads without names (helpful to route between mapped cities or to the next unmapped place) and mapping every unknown building (most information can be added to a node if the building isn't there, even without a GPS people can survey and add this information themselves). I have been thinking about these people who like sitting at a hot computer. Now I am doing house numbers/names it could be helpful to have someone trace building outlines for me so that I have more free time to go outside and get the information to add to and correct the details. I've briefly asked in irc (and had no takers), but when I have I included details of where to not go beyond, because I know some areas could easily be confused as to what they are without local knowledge. This is the case for OS StreetView, and the Surrey Aerial Imagery (still confused on the latter license). It might be nice to have somewhere to request help from 'armchair mappers' this could also be good for the crisis requests. -- Gregory o...@livingwithdragons.com http://www.livingwithdragons.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Ed Avis wrote on 24/05/2010 15:05: It appears the choice for buildings is a fight between OS maps, which are likely derived from high-resolution aerial photos but have been simplified, and the somewhat lower-resolution photo images available to OSM. It is not really possible to survey building shapes on the ground since GPS isn't precise enough, even if we had enough mappers to walk round the outside of every building. In London the Yahoo photos are adequate for tracing streets, but trying to get buildings from them is a bit ropey. Hence my feeling that the OS data is of higher quality, even though it's clearly a simplification of the real shape. But in other, less crowded parts of the country a semi-automated trace from aerial photos (using the Fuzzer JOSM plugin you mention) might be a better way. (Indeed, it might be fun to trace the whole country using both methods and then highlight differences between the two.) I still believe we could do *something* to get reasonably good building shapes into the map without waiting for the man-years needed to hand-survey them all. Even in an area which is not any mapper's particular 'territory'. The workflow might be to view the aerial photograph with the OS-traced building shapes on top, and then either press a button to import the whole area or select individual shapes. Taking the lead from StreetView in my area, the shapes around are better than nothing and are good for making sense of the map. With appropriate tagging, which is trivial with a bulk import, then it becomes easy enough to have a to-do list. Areas of little interest to people will be populated adequately, and areas where people are interested, they should know from the source (perhaps even an automated note) that they have carte-blanche to improve it. A Wiki-Map does have the danger of trying to be all things to all men, and it is interesting to see from a single source that the cyclists can produce an appropriate map different from the general. If people are really uncomfortable with the impurity of the data (in the sense of reliability not licence), then the right approach to me is to have a specific tag that is internationally agreed to be unverified/suspect and then map producers can filter or represent that data as they deem appropriate, without the map editors needing to prejudge an appropriate solution. It would also be useful to then make PotLatch et al sensitive to the tag. (BTW, it may be that this already exists, but there does not seem to be anything from my cursory look). That is not just for this extracted data, there are times I have looked at an area I know well and can't believe it does not mark a path that I know well. I would rather put the path in temporarily with a warning that it needs to be verified for exact alignment, and gets on to a to do list, than not mark it at all. I'll walk it eventually, but on a map it might get noted and verified by someone else. Spenny ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On 24 May 2010 14:56, Richard Fairhurst rich...@systemed.net wrote: Robert Whittaker (OSM) wrote: My understanding is that the current terms from OS are incompatible with ODbL (in particular the part that allows produced works to be released to the public domain). This is a canard and I wish it would stop coming up. ODbL does _not_ say that Produced Works can be released entirely without restriction (US public domain). 4.3 is very clear that if you Publicly Use a Produced Work, You must include a notice associated with the Produced Work reasonably calculated to make any Person that uses, views, accesses, interacts with, or is otherwise exposed to the Produced Work aware that Content was obtained from the Database, Derivative Database, or the Database as part of a Collective Database, and that it is available under this License. OS OpenData is released under an attribution-only licence (compatible with CC-BY) and the terms of attribution are, in my entirely unqualified view, satisfied by ODbL 4.3. My reading of 4.3 is that you would have to tell people that the image was derived from OSM and that the OSM database is available under ODbL. As far as I can see, 4.3 contains nothing to specify what license you are or aren't allowed to release the produced work under, nor anything to require you to maintain a specific attribution statement from the third-party data supplier such as OS. If I'm allowed under ODbL to release an image with only the statement Contains information from DATABASE NAME, which is made available here under the Open Database License (ODbL). as suggested by the ODbL text, then this is surely in contravention of the attribution requirements specified by OS as (a) I haven't included their specific attribution/copyright text, and (b) I haven't had to place any restrictions on other users of my image that would require them to provide any such attribution either. Both of the following links seem to suggest you should be able to release produced work images in this way: http://wiki.openstreetmap.org/wiki/Open_Data_License/Use_Cases#Using_OSM_data_in_a_raster_map_for_a_book.2C_newsletter.2C_website.2C_blog_or_similar_work http://wiki.openstreetmap.org/wiki/Open_Data_License_FAQ#How_does_this_affect_Wikipedia_and_other_projects_that_want_to_use_our_maps.3F Anyway, even if this turns out to be a non-issue, there is still the problem of getting OS to agree to the new contributor terms if OSMF decides they need all OSM data under them. I really can't see OS being happy with either OSMF's right to re-license or the terms of DbCL. -- Robert Whittaker ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Robert Whittaker (OSM) wrote: My reading of 4.3 is that you would have to tell people that the image was derived from OSM and that the OSM database is available under ODbL. To comply with ODbL for data obtained from OSM, you have to at least provide attribution to OSM. That does not preclude that the data may have other attribution requirements, and it does not prevent you from fulfilling them. cheers Richard -- View this message in context: http://gis.638310.n2.nabble.com/building-shapes-from-OS-Street-View-tp5091506p5094362.html Sent from the Great Britain mailing list archive at Nabble.com. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On 24 May 2010 16:42, Richard Fairhurst rich...@systemed.net wrote: Robert Whittaker (OSM) wrote: My reading of 4.3 is that you would have to tell people that the image was derived from OSM and that the OSM database is available under ODbL. To comply with ODbL for data obtained from OSM, you have to at least provide attribution to OSM. That does not preclude that the data may have other attribution requirements, and it does not prevent you from fulfilling them. Although it doesn't prevent any voluntary fulfilment, the ODbL terms give you explicit rights to use the database in any way you want without violating any copyright/contract/database rights in the database, as long as you follow the various requirements. There's no requirement to provide further attribution on produced works, so for produced works from an ODbL database you would not be violating any database rights were you to omit any other attribution requirements on produced works. The only other way to force users to use attribution would be via copyright on individual data items. But the proposal is to license the individual items in OSM under DbCL, which means there would be no additional restrictions there. Thus ODbL+DbCL grants users the right not to have to include additional attribution statements on produced works, provided they follow the rest of the requirements of ODbL. (This usually includes releasing the database that the work was produced from under ODbL, and the database may require additional copyright notices attached to it, but not the produced work. This link back to the database may be enough to satisfy some people's attribution requirements, but it won't necessarily cover all such requirements.) With no way to force users to add specific attribution text to produced works, if a database contains data that requires such attribution, I would conclude that the resulting database cannot legally be released under ODbL+DbCL. Were someone to do so, they'd be giving people a license to do stuff that they don't have the right to offer. (Kind of like releasing an image obtained under CC-By as CC0.) -- Robert Whittaker ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
TimSC mapp...@... writes: Hi all, I have done a small test of automatically tracing buildings from OS Street View. I have limited this to Wood Street Village, near Guildford. That is a nice piece of work. It is not as good as you could get from the Surrey aerial photographs but no worse and more consistent than tracing Yahoo pictures. One thing to watch is that it only imports the orange inside of public buildings. -- Andrew ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On 23 May 2010 20:00, TimSC mapp...@sheerman-chase.org.uk wrote: I guess the fundamental question is, is this quicker than doing the whole thing manually? For buildings that are semi-detached or terraces, the terracer plugin seems to pay attention to the order the nodes were created/numbered, and thus on which side to split the building up (I suppose if it's fairly square-shaped). I don't see that a colour-reading auto-tracer could decide on which side to start drawing the building. For this reason I think it is quicker to use the building plugin to trace and then be ready to split up for numbering. But don't let me discourage your work and anyone who would find it useful. It is probably that this case is based on my current mapping of lots of square-ish buildings that are often semi-detached. Actually, we haven't thought if this would be helpful in any areas if altered for use on ponds/lakes (not really rivers broken by many bridges) and/or green woods/parks. -- Gregory o...@livingwithdragons.com http://www.livingwithdragons.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On 23 May 2010 20:00, TimSC mapp...@sheerman-chase.org.uk wrote: I have done a small test of automatically tracing buildings from OS Street View. I have limited this to Wood Street Village, near Guildford. I have not done any manual improvements but these should be done to improve the quality. I am not doing that yet so people can take a look at the result. It seems acceptable to me. I have implemented the code in python and uploaded it using JOSM. There was a glitch with duplicate nodes which JOSM validator fixed, I need to root out the cause in my code. http://osm.org/go/eurUp7x0Q- Nice work. :-) However, not wanting to pour cold water on everyone's efforts with OS Open Data, but before we all invest too much time in using OS OpenData... My understanding is that the current terms from OS are incompatible with ODbL (in particular the part that allows produced works to be released to the public domain). OS might well be persuaded to dual license under ODbL-compatible terms, but I'm not sure they'll be prepared to agree to the give OSMF the right to re-license under as-yet unspecified terms part of the proposed new contributor terms. If OSM does indeed change to ODbL and/or OSMF want to ensure they have the right to re-license content we may well have to remove all OS OpenData derived data from OSM. This would be a great shame, and I'd hope that we will be able to work something out. But would be an even greater shame if people had invested lots of time in importing / tracing stuff that later had to be removed. We should probably get someone from OSMF LWG to contact OS to see what options they might consider. In the mean time, if we do use OS OpenData in OSM, we should be very careful to add proper source tags so it can be identified and removed later if necessary. Robert. -- Robert Whittaker ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
From: Robert Scott li...@humanleg.org.uk That's great! I can stop reading about Harris operators. I totally agree about orthogonal snapping. Orthogonal snapping would be useful more generally - do any of the editors have this feature for manually drawn buildings etc.? -- Steve ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Sat, Apr 10, 2010 at 9:23 AM, Steve Doerr steve.do...@blueyonder.co.uk wrote: Orthogonal snapping would be useful more generally - do any of the editors have this feature for manually drawn buildings etc.? JOSM has an Orthogonalise shape option which is very useful for buildings. Glenn. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
It's worth noting that the Yahoo aerial photography is also out of date; in some cases [1] people have traced streets from the photo which bear no relation to what's on the ground. Yet nobody suggests we should stop tracing from it. Yes they do. http://lists.openstreetmap.org/pipermail/talk/2007-September/017830.html I've slightly changed my mind since then, but anyway. Dave ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Glenn wrote: JOSM has an Orthogonalise shape option which is very useful for buildings. And a terracer plugin which I find useful for converting traced buildings to semi-detached* (or however many) properties. Ed * Slight issue when the width of the two semi-detached houses together is less than their depth as it then splits the rectangle on the wrong axis, but this seems fairly rare around here (and I now know how to rotate objects in JOSM as a result). ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Saturday 10 April 2010, TimSC wrote: Converting edge fragments to polygons is the slow step at the moment - about 15 minutes a tile. I am using the approach describe in the link below. Fortunately, I know a bit of Boost.Python and C++ if we need the speed. I suspect a better algorithm in python could improve the speed issue rather than resorting to C++. If needs be, and other algorithms fall short, the advantages c++ has are things like ability to optimize for cache behaviour, ability to choose algorithms for your data structures (such as lists) which I imagine are getting hammered by your approach. A last resort though. http://losingfight.com/blog/2007/08/28/how-to-implement-a-magic-wand-tool/ I am also seeing the limitations of my approach. Problems arise from the lack of image resolution and the anti-aliasing of the colours in the image. Since I am using a binary classification by colour for selecting pixels, it tends to result in rounded corners (due to the colour blending into the backgound). The polygon simplification then has to descriminate between a rounded corner due to anti-aliasing and corner which is real. Given the resolution, a straight edge might only be 2 or 3 pixels long, and a rounded corner has a radius of about... 2 or 3 pixels. But then, these building shapes are also a total nightmare to manually survey. Example attached (you will probably need to zoom in): Indeed. The approach I was going to take was taking the buildings as anti-aliased grayscale ( which I guess I would have to be generated by tuning a few heuristics about which indexed colours to pick ) and use a corner finding algorithm on them. I was hoping to be able to get sub-pixel accuracy with this approach (corner detectors are perfectly capable of it with grayscale data), but I still have a few papers to read. I was thinking momentarily of a hybrid approach, using detected corners to more precisely position nodes. As far as the orthogonalizer idea goes, I think a simple refinement would need to be made - orthogonalization threshold would need to be inversely proportional to segment lengths. Lengths that are short relative to pixel size will have more quantization errors than long segments. I have some ideas for a better algorithm (based on active contour models), but that is pretty complex. I will give that some thought. Basically, we need to segment the shape but not by simply binary selecting pixels inside or outside the shape (and it can try to be orthogonal, if possible). The code I have does provide a good initialisation of the model, so it is hardly wasted effort. If anyone has any better ideas, you can have a copy of my python code to try things. You've done a lot better than me - I'm still at the 'reading papers' stage ;) robert. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Andy Allan gravityst...@... writes: I hope you have seen the vast tracts of London that have building outlines in OSM already - all of much higher detail than Street View? I don't know about you, but for me the OS building outlines appear to be of far higher detail than I can map myself by surveying or by tracing from the relatively low-resolution, not-quite-overhead aerial photos available to OSM. -- Ed Avis e...@waniasset.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Andy Robinson (blackadder-lists ajrli...@... writes: But what is the point of just doing building=yes. Does that really add to OSM? Surely tracing buildings (with aids or not) would be better associated with address data inclusion rather than just making a pretty map? You might consider it analogous to streets: at first they were mostly traced from aerial photos, and then mappers visited on the ground to fill in names (and other things as a side effect). This is certainly what I've been doing for the past couple of years. So yes, it would be great to trace the buildings from the OS maps (which would be just as accurate as tracing them from low-res aerial photos) and get them into OSM, even if the address is missing. If the NoNames map then highlighted buildings missing address info, that would motivate people to get out and add the addresses. (FWIW, I think just building shapes without any addresses are still useful, especially on council estates and other areas that lack clearly defined streets.) -- Ed Avis e...@waniasset.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Hi Tim, That is exactly the sort of thing I had envisaged writing - you have nearly finished before I got started - well done! Graham. On 9 April 2010 22:25, TimSC mapp...@sheerman-chase.org.uk wrote: Hi again, I have been working on auto tracing buildings and I'm making progress. I was slightly encouraged by Ed Avis's comments. I think one underlying difference is peoples attitude to omissions in map data. Many people think they are a good thing, particularly since they encourage the community to do high quality surveying. But I think omissions are bad in terms of actually using the map. I don't think we should be using the main map to gauge our progress. I suspect what we need is good meta data - how and when data is sourced. Anyway enough rambling... Tracing buildings. I have been using the original images, since image transformations tend to introduce degradation of quality. I use colour to select building pixels, then form edge fragments, then form polygons, then simplify the polygons using the Douglas-Peucker algorithm, then group them so we get inner and outer edges, then tranform image coordinates to GBOS then to WGS84 via OSTN02 (I ported the perl code to python), then save as OSM format and load back into JOSM. Screenshot: http://timsc.dev.openstreetmap.org/dev/josm-building-outlines.png The next steps are to improve the quality of the polygon shapes, possibly by checking if the edges are nearly orthogonal, and if so making them completely orthogonal. Also I need to write a filter to check for buildings in the area, to avoid importing duplicate buildings. I need to look at the simplification, as sometimes an extra node is added to a polygon (the initial node used as the start of the algorithm). I am also considering detecting roads that overlap buildings in the source images, since this is probably the biggest loss of quality. The result I am getting is already more spatially detailed than my own survey of the University of Surrey campus (although not as rich in information). In the medium term, I will import some buildings once I have the quality I want. I want to minimise manual work in JOSM but I don't rule it out. I will only be working in the Guildford area - it's my data to gamble around there :) TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb -- Dr. Graham Jones Hartlepool, UK email: grahamjones...@gmail.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
blatant lieYeah, me too. I was just about to do that! /blatant lie Fantastic! - Original Message - From: Graham Jones To: TimSC Cc: talk-gb@openstreetmap.org Subject: Re: [Talk-GB] building shapes from OS Street View Date: Fri, 9 Apr 2010 22:32:40 +0100 Hi Tim,That is exactly the sort of thing I had envisaged writing - you have nearly finished before I got started - well done! Graham. On 9 April 2010 22:25, TimSC mapp...@sheerman-chase.org.uk wrote: Hi again, I have been working on auto tracing buildings and I'm making progress. I was slightly encouraged by Ed Avis's comments. I think one underlying difference is peoples attitude to omissions in map data. Many people think they are a good thing, particularly since they encourage the community to do high quality surveying. But I think omissions are bad in terms of actually using the map. I don't think we should be using the main map to gauge our progress. I suspect what we need is good meta data - how and when data is sourced. Anyway enough rambling... Tracing buildings. I have been using the original images, since image transformations tend to introduce degradation of quality. I use colour to select building pixels, then form edge fragments, then form polygons, then simplify the polygons using the Douglas-Peucker algorithm, then group them so we get inner and outer edges, then tranform image coordinates to GBOS then to WGS84 via OSTN02 (I ported the perl code to python), then save as OSM format and load back into JOSM. Screenshot: http://timsc.dev.openstreetmap.org/dev/josm-building-outlines.png The next steps are to improve the quality of the polygon shapes, possibly by checking if the edges are nearly orthogonal, and if so making them completely orthogonal. Also I need to write a filter to check for buildings in the area, to avoid importing duplicate buildings. I need to look at the simplification, as sometimes an extra node is added to a polygon (the initial node used as the start of the algorithm). I am also considering detecting roads that overlap buildings in the source images, since this is probably the biggest loss of quality. The result I am getting is already more spatially detailed than my own survey of the University of Surrey campus (although not as rich in information). In the medium term, I will import some buildings once I have the quality I want. I want to minimise manual work in JOSM but I don't rule it out. I will only be working in the Guildford area - it's my data to gamble around there :) TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb -- Dr. Graham Jones Hartlepool, UK email: grahamjones...@gmail.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb -- ___ Surf the Web in a faster, safer and easier way: Download Opera 9 at http://www.opera.com Powered by Outblaze ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Hey, That's great! I can stop reading about Harris operators. I totally agree about orthogonal snapping. How well would this scale up to the whole country? (!! Not automatically importing the results of course !!) I'm thinking about tile/batch sizes, tile boundary issues, any necessity for porting parts to c++ for speed etc. robert. On Friday 09 April 2010, TimSC wrote: Hi again, I have been working on auto tracing buildings and I'm making progress. I was slightly encouraged by Ed Avis's comments. I think one underlying difference is peoples attitude to omissions in map data. Many people think they are a good thing, particularly since they encourage the community to do high quality surveying. But I think omissions are bad in terms of actually using the map. I don't think we should be using the main map to gauge our progress. I suspect what we need is good meta data - how and when data is sourced. Anyway enough rambling... Tracing buildings. I have been using the original images, since image transformations tend to introduce degradation of quality. I use colour to select building pixels, then form edge fragments, then form polygons, then simplify the polygons using the Douglas-Peucker algorithm, then group them so we get inner and outer edges, then tranform image coordinates to GBOS then to WGS84 via OSTN02 (I ported the perl code to python), then save as OSM format and load back into JOSM. Screenshot: http://timsc.dev.openstreetmap.org/dev/josm-building-outlines.png The next steps are to improve the quality of the polygon shapes, possibly by checking if the edges are nearly orthogonal, and if so making them completely orthogonal. Also I need to write a filter to check for buildings in the area, to avoid importing duplicate buildings. I need to look at the simplification, as sometimes an extra node is added to a polygon (the initial node used as the start of the algorithm). I am also considering detecting roads that overlap buildings in the source images, since this is probably the biggest loss of quality. The result I am getting is already more spatially detailed than my own survey of the University of Surrey campus (although not as rich in information). In the medium term, I will import some buildings once I have the quality I want. I want to minimise manual work in JOSM but I don't rule it out. I will only be working in the Guildford area - it's my data to gamble around there :) TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On 6 April 2010 12:46, TimSC mapp...@sheerman-chase.org.uk wrote: Hi again, Thanks for the feedback on building traces. The consensus seems to be for a JOSM plugin while others saying all surveying should be done on the ground. Personally, I'd be happy to see a JOSM plugin similar to the Lakewalker plugin: http://wiki.openstreetmap.org/wiki/Lakewalker For those not familiar with it, you activate it, then click on a lake or similar. The plugin creates a way around the lake, which can then be manually checked/corrected before the edits are uploaded to OSM. Russ ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Tue, Apr 6, 2010 at 12:46 PM, TimSC mapp...@sheerman-chase.org.uk wrote: In response to the comment no imports ever, I would point out that building imports is a completely different situation than that of public roads. A glance at OS Street View suggests that about 99% of buildings are not publically accessible. If we use only manual surveying, we can only achieve coverage of about 1%. I don't think that is satisfactory. Imports are therefore very much appropriate for buildings. You're missing the point on several levels. For buildings it's quite possible to trace the outlines from aerial imagery, where we have it. And in some parts of the country, we have better imagery than the building outlines shown on Street View - yahoo, and soon the Surrey imagery, for starters. So it's not a case of Street View or nothing. I hope you have seen the vast tracts of London that have building outlines in OSM already - all of much higher detail than Street View? None of this depends on whether the building is publicly accessible. Also, you are confusing the use of multiple sources for editing (GPS, aerial, maps), with that of importing. Imports is an orthogonal discussion to that of whether the building outlines in Street View are useful. Please don't confuse the two issues. If you are not talking about bulk imports then please don't call your ideas imports, otherwise you confuse people as to your intentions. There are people who are supportive of imagery recognition to help editors, who are strongly opposed to bulk imports. Cheers, Andy ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Tue, Apr 6, 2010 at 1:22 PM, Robert Scott li...@humanleg.org.uk wrote: I'd say about 95% of buildings are rectangles. About 99% of buildings are purely orthogonal lines. We need to be careful about extracting shapes from products that are known to be downsampled. A quick look at Street View in my area shows that OSM has more detail in the building outlines than Street View, suggesting to me that MasterMap outlines have been simplified (often to rectangles) to make this particular product. We need to realise that whilst we map to a high level of detail and keep those details in our end products, the OS don't and often have simplified outputs. So it's a false assumption that the buildings in Street View are accurate or better than OSM can create by other means. Cheers, Andy ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Tue, Apr 6, 2010 at 5:26 PM, TimSC mapp...@sheerman-chase.org.uk wrote: Andy Allan wrote: On Tue, Apr 6, 2010 at 12:46 PM, TimSC mapp...@sheerman-chase.org.uk wrote: If we use only manual surveying, we can only achieve coverage of about 1%. I don't think that is satisfactory. Imports are therefore very much appropriate for buildings. You're missing the point on several levels. For buildings it's quite possible to trace the outlines from aerial imagery, where we have it. And in some parts of the country, we have better imagery than the building outlines shown on Street View - yahoo, and soon the Surrey imagery, for starters. So it's not a case of Street View or nothing. I hope you have seen the vast tracts of London that have building outlines in OSM already - all of much higher detail than Street View? It's not vast, it doesn't even get to the edge of the underground zone 1. And the detail is comparable to my eye, except for many omissions in OSM. I am not sure how you are quantifying quality. I suspect that the OSM data is more up to date (even if Yahoo is a few years out of date), but OSM still very incomplete even in this supposedly well mapped area. I suspect with the few OSM contributors doing tracing the various sources and given their limited coverage, we are still looking like converging on poor overall coverage given years of effort, so my original point still stands. I say we can compliment our other sources with automatic tracing (be that by importing or editor tools). I guess the question is how much progress can we make on building outlines over different time scales, given different approaches? If you are not talking about bulk imports then please don't call your ideas imports, otherwise you confuse people as to your intentions. I am discussing automatic tracing which applies to both editor tools and imports. There is no rule that I have to discuss one option exclusively. But I was leaning towards more the import paradigm, while the majority seems to be for editor tools. Andy, from my perspective, you have not given a single justified reason against doing imports, so I can't really rebut your position (although other people have made valid points). I suggest you get a bit more constructive and outline your vision for the way ahead on this issue? Continue, as is, with Yahoo and so on? The thing we're looking to not have is automatic imports. London has a lot of buildings, but only in certain areas. What I don't want to have to do is wake up one morning to discover someone has helpfully imported auto-detected rectangles over the top, meaning I have to spend the next three days/years cleaning up the data. If all you want to do is load some buildings into an area (however that's implemented), fix it up to avoid duplicates and conflicts with existing data such as roads, and upload that, then fine. If you want to spend the time comparing against other sources too then even better. If you want to dump buildings into the entire country and hope that everybody gets around to fixing all the problems in their area afterwards, then please don't. Basically: please don't break the map :-) Other than that, tracing OS street view is by far the best source of building outlines we will have in much of the UK at the moment. Dave ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Tue, 2010-04-06 at 18:07 +0100, Dave Stubbs wrote: Basically: please don't break the map :-) perhaps a stupid question... Is there no version control? I couldn't find anything on the wiki about it. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Tue, Apr 6, 2010 at 6:14 PM, Henry Gomersall h...@cantab.net wrote: On Tue, 2010-04-06 at 18:07 +0100, Dave Stubbs wrote: Basically: please don't break the map :-) perhaps a stupid question... Is there no version control? I couldn't find anything on the wiki about it. Sure. But if you go and import everything, and I go and unimport everything, that's not much fun for either of us. Dave ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Mon, Apr 5, 2010 at 5:57 PM, TimSC mapp...@sheerman-chase.org.uk wrote: I guess the questions we have to address are: is this data worth having in OSM? Yes are there any better sources of building outline? OS Mastermap. But since we won't get access to that any time soon If we do want this data, it seems to be only available as a raster layer. Yes. So we can trace the areas that we're working on, like we've been using Yahoo! Converting raster map data to vector data is non trivial but I think it is achievable. Ummm The building colour in the raster map seems to be unique. The raster maps could be selected by colour, vectorised and simplified (to remove redundant nodes). aaahh Buildings could be imported ... No. No no no no a thousand times no. Any general thoughts on buildings and imports? Don't import stuff. I'll be happy to see you import things that you are willing, personally, to maintain and update, and I'd prefer you imported using Potlatch or JOSM and used the Street View, Yahoo, GPS and local knowledge all mixed in as your sources. But no bulk imports of automatically generated buildings please. Cheers, Andy ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Tim, I think this is a really good idea, and is one of the main benefits of the StreetView data. I have been wondering how to do this, but haven't got far. I would like to see a plugin for josm that takes a raster input (landsat, yahoo, StreetView) and processes it into 'draft' ways around areas of constant(ish) colour - the user then tidies it up and tags it before uploading (ie I would be very wary of a 'blind' import!). I think streetview would be the easiest because of the high contrast - I would like to see it work for landsat because I am colourblind and can't trace the outline of woods, and the North Yorkshire moors need some more detail!. Someone (I think it was Mike DuPont) reported doing this with gdal_contour, but I haven't tried it yet, and I haven't looked at how to turn this into a josm plugin. If I'd thought of it earlier I would have suggested this as a GSoC student project! Regards Graham. On 5 April 2010 17:57, TimSC mapp...@sheerman-chase.org.uk wrote: Hi all, I was looking at the available OS data and one of the things they have but is not really in the current OSM database is building shapes. Individual buildings appear in the Street View data. The VectorMap District data seems to focus on land use and only has important buildings. The Street View data is much more complete in terms of individual buildings. I guess the questions we have to address are: is this data worth having in OSM? and are there any better sources of building outline? I think it would be a valuable addition for highly detailed mapping of urban areas, campuses, etc. The other sources of building outlines I know of are the 1st edition OS sheets (which are rather old), Yahoo imagery (which takes work to trace), and manual surveying (which is a major hassle since buildings tend to throw off GPS positions). Another source would be preferable to these. If we do want this data, it seems to be only available as a raster layer. (Does anyone know if this will be available as a vector layer?) Converting raster map data to vector data is non trivial but I think it is achievable. The building colour in the raster map seems to be unique. The raster maps could be selected by colour, vectorised and simplified (to remove redundant nodes). Since we have a significant number of buildings mapped in the UK, we could presume that we don't want to overwrite or duplicate what is already there. Buildings could be imported if it would not overlap with an existing building in OSM. One problem is some buildings are marked as leisure=stadium without a building=*. We might end up with duplicates of stadiums, leisure centres, churches and so on. Would we want the import to be more cautious to prevent this? I won't be importing anything until the rectification of Street View is complete (and I get a feel for the consensus on the mailing list) but I have demoed most of the method in python using the shapely module to do some geometry transforms. Any general thoughts on buildings and imports? Will this data be officially available in vector form at some point? We don't seem to have much comment on the legal issues and the implications of ODbL yet. Do we have a view as to if our attribution is sufficient? Regards, TimSC ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb -- Dr. Graham Jones Hartlepool, UK email: grahamjones...@gmail.com ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
On Monday 05 April 2010, Andy Allan wrote: Any general thoughts on buildings and imports? Don't import stuff. I'll be happy to see you import things that you are willing, personally, to maintain and update, and I'd prefer you imported using Potlatch or JOSM and used the Street View, Yahoo, GPS and local knowledge all mixed in as your sources. But no bulk imports of automatically generated buildings please. What about supervised 'imports', using a josm/potlatch plugin (a la cadastre-fr) to do vectorization and manually merging the results street by street? What about automatic generation of buildings countrywide to an osm layer that users manually merge with osm.org, again, street by street or block by block? I'm just cowering at the hundreds of thousands of man hours of unnecessary clickety-click-click-click that could be hugely accelerated by machine vision algorithms. robert. ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
Re: [Talk-GB] building shapes from OS Street View
Kevin Peat wrote: Sent: 05 April 2010 7:50 PM To: David Earl; Talk-GB@openstreetmap.org Subject: Re: [Talk-GB] building shapes from OS Street View In the absence of vector data I agree that a controlled way of auto-tracing the building outlines (a JOSM plug-in would be ideal for me) is the way to go. But what is the point of just doing building=yes. Does that really add to OSM? Surely tracing buildings (with aids or not) would be better associated with address data inclusion rather than just making a pretty map? For my area, unless something like this comes along there will never be building outlines in OSM as the local demographics mean mappers are in short supply and I can't imagine that those that there are would want to manually trace 10s of thousands of buildings anyway. I don't think the we shouldn't sully OSM with OS data argument stands up as looking at my area (Devon) most of the coastline + almost all names of natural features and numerous other stuff has come from the NPE and 1st Edition maps. The StreetView coastline and waterways data is way better than what we currently have here and unless there is better data coming in the near future then we should trace this stuff in asap. Which is fine in the absence of anything else, or dedicated mappers on the ground. Eventually mappers will visit those areas and improve them, I regularly do and I'm often removing the NPE tags because I have a better source or an actual tracklog. Cheers Andy Kevin On 5 April 2010 19:14, David Earl da...@frankieandshadow.com wrote: On 05/04/2010 18:41, Graham Jones wrote: I would like to see a plugin for josm that takes a raster input (landsat, yahoo, StreetView) and processes it into 'draft' ways around areas of constant(ish) colour - the user then tidies it up and tags it before uploading (ie I would be very wary of a 'blind' import!). On 05/04/2010 18:52, Robert Scott wrote: What about supervised 'imports', using a josm/potlatch plugin Much, much better IMO. I dread the idea of any automated imports for the UK into OSM. Tools to automate tracing while being manually aware of what is already there and the flaws in the automation is so much better than trying to import and screwing up what's already there, duplicating stuff and adding poor quality automation flaws. David ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.791 / Virus Database: 271.1.1/2792 - Release Date: 04/05/10 07:32:00 ___ Talk-GB mailing list Talk-GB@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-gb
