Re: [OSM-talk] Too many nodes?
> > > This bezier stuff is nice for the renderers, but it shouldn't be a > > > substitute for having enough nodes to define the curve. Don't forget > > > are other data consumers/renderers that may not have the ability to do > > > bezier curves. Extra nodes can always be reduced by using a > > > algorithm if the number of nodes is a problem for a particular > > While I agree with you what is 'enough'? I'm doing hi resolution maps > > for print - effectively zoom level 20 maybe 21 - and it would be > > unreasonable to expect people to put in enough nodes to make that look > > smooth! > Of course, "enough" is subjective. I'm specifically thinking of maps on GPS > devices. A certain amount of jaggedness is expected, but it should be a > reasonable approximation of the curve. Sorry - I think my previous email came across badly... anyway: You make a good point - I was thinking of the number of points in terms of the quality of the output I want but it probably makes more sense to think in terms of the reliability of the input data. A guideline of 'the limit of the quality of your GPS / data source' sounds like very good advice. It comes down to that fundamental conflict of the whole OSM project - what we capture is data but what most of us want out of the end is good quality maps! -- Brian ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
On Sat, Apr 19, 2008 at 10:39 AM, Brian Quinion < [EMAIL PROTECTED]> wrote: > > > Interesting, Artem sent a mail in January that he was working on it > > > and I foolishly assumed that meant he was working on it in SVN. > > > However looking through the source it seems you are right, there's > > > nothing there. > > > I'll bug him to release a patch at least so we can play with it. > > Many thanks! > > > This bezier stuff is nice for the renderers, but it shouldn't be a > > substitute for having enough nodes to define the curve. Don't forget > there > > are other data consumers/renderers that may not have the ability to do > > bezier curves. Extra nodes can always be reduced by using a > simplification > > algorithm if the number of nodes is a problem for a particular > application. > > While I agree with you what is 'enough'? I'm doing hi resolution maps > for print - effectively zoom level 20 maybe 21 - and it would be > unreasonable to expect people to put in enough nodes to make that look > smooth! > > Like everything else bezier smoothing is another tool... > > Cheers, > -- > Brian > Of course, "enough" is subjective. I'm specifically thinking of maps on GPS devices. A certain amount of jaggedness is expected, but it should be a reasonable approximation of the curve. Karl ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
> > Interesting, Artem sent a mail in January that he was working on it > > and I foolishly assumed that meant he was working on it in SVN. > > However looking through the source it seems you are right, there's > > nothing there. > > I'll bug him to release a patch at least so we can play with it. Many thanks! > This bezier stuff is nice for the renderers, but it shouldn't be a > substitute for having enough nodes to define the curve. Don't forget there > are other data consumers/renderers that may not have the ability to do > bezier curves. Extra nodes can always be reduced by using a simplification > algorithm if the number of nodes is a problem for a particular application. While I agree with you what is 'enough'? I'm doing hi resolution maps for print - effectively zoom level 20 maybe 21 - and it would be unreasonable to expect people to put in enough nodes to make that look smooth! Like everything else bezier smoothing is another tool... Cheers, -- Brian ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
On Sat, Apr 19, 2008 at 5:52 AM, Martijn van Oosterhout <[EMAIL PROTECTED]> wrote: > On Sat, Apr 19, 2008 at 2:23 PM, Brian Quinion > <[EMAIL PROTECTED]> wrote: > > > IIRC, Mapnik supports bezier hinting for quite a while now, just > > > no-one has gone and updated the stylesheet to use it. > > > > I was looking for these options the other day for a map I was doing > > but came to the conclusion that they had not yet been exposed at the > > stylesheet level. > > > > Do you have a short example of how to enable this? > > Interesting, Artem sent a mail in January that he was working on it > and I foolishly assumed that meant he was working on it in SVN. > However looking through the source it seems you are right, there's > nothing there. > > I'll bug him to release a patch at least so we can play with it. > > Have a nice day, > -- > Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ > This bezier stuff is nice for the renderers, but it shouldn't be a substitute for having enough nodes to define the curve. Don't forget there are other data consumers/renderers that may not have the ability to do bezier curves. Extra nodes can always be reduced by using a simplification algorithm if the number of nodes is a problem for a particular application. Karl ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
On 19/04/2008, Jo <[EMAIL PROTECTED]> wrote: > Ari Torhamo schreef: > > > > I would just like to add to the other replies that before (re)moving > nodes you should look at their properties. Sometimes they are at a > specific place for a reason (bus stop, crossing, etc) > Using JOSM its helpful that any node with a tag is displayed as a larger square dot that nodes without a tag. Its easy then to see which nodes you can delete without affecting any other data. Cheers Andy > Polyglot > > > ___ > talk mailing list > talk@openstreetmap.org > http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk > -- Andy Robinson ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
On Sat, Apr 19, 2008 at 2:23 PM, Brian Quinion <[EMAIL PROTECTED]> wrote: > > IIRC, Mapnik supports bezier hinting for quite a while now, just > > no-one has gone and updated the stylesheet to use it. > > I was looking for these options the other day for a map I was doing > but came to the conclusion that they had not yet been exposed at the > stylesheet level. > > Do you have a short example of how to enable this? Interesting, Artem sent a mail in January that he was working on it and I foolishly assumed that meant he was working on it in SVN. However looking through the source it seems you are right, there's nothing there. I'll bug him to release a patch at least so we can play with it. Have a nice day, -- Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
Hi, > IIRC, Mapnik supports bezier hinting for quite a while now, just > no-one has gone and updated the stylesheet to use it. I was looking for these options the other day for a map I was doing but came to the conclusion that they had not yet been exposed at the stylesheet level. Do you have a short example of how to enable this? Cheers, -- Brian ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
On Sat, Apr 19, 2008 at 1:08 PM, Ben Laenen <[EMAIL PROTECTED]> wrote: > Well, before using it, I'd like to ask to have a way to disable the > curves as well (and I'd even prefer to see nice curves for roads > disabled by default). When roads or other features (like the water > borders in a port) have straight corners instead of curves, it gives > awkward results like extra bulges in [EMAIL PROTECTED] On mapnik you have access to the properties: it's not a global setting. So we can only bezier highway=foo things and nothing else. But if you're proposing having it off by default then I think the status quo is fine. Have a nice day, -- Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
On Saturday 19 April 2008, Martijn van Oosterhout wrote: > IIRC, Mapnik supports bezier hinting for quite a while now, just > no-one has gone and updated the stylesheet to use it. Well, before using it, I'd like to ask to have a way to disable the curves as well (and I'd even prefer to see nice curves for roads disabled by default). When roads or other features (like the water borders in a port) have straight corners instead of curves, it gives awkward results like extra bulges in [EMAIL PROTECTED] Ben ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
On Sat, Apr 19, 2008 at 1:30 AM, Ari Torhamo <[EMAIL PROTECTED]> wrote: > I remember reading this bezier system being planned, but understood that > it wouldn't be nearly ready yet. Is it indeed ready for use, and will it > be the default method for rendering maps? Is it coming to Mapnik too? > What about other renderers? If it will be used for all rendering in the > future, that will make drawing nice curves much easier :-) IIRC, Mapnik supports bezier hinting for quite a while now, just no-one has gone and updated the stylesheet to use it. Have a nice day, -- Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
Ari Torhamo schreef: > Hello, > > I have a question regarding the amount of nodes that one may use to draw > a road, and whether the amount of nodes used has a considerable effect > on the speed of the OpenStreetMap. > > I did my first edits to OSM a few days ago. I'll get a GPS device soon, > but so far my only edits have been adding street names and making roads > more accurate by adding more nodes to curves, etc. Following these > edits, another person who has edited the same area earlier, contacted me > and told me not to add unnecessary nodes to roads that he has made long > time ago and added that he has already removed the unnecessary nodes. > According to him using many nodes slows down the rendering and routing. > > This made me wonder, what really is the right amount of nodes to use, > when one want's the curves to be right and look really nice, but not to > cause any problems by this. Can nodes be added as long as there are > visible jaggies on the rendered map - even small ones - and just leave > out the ones which have no affect on rendering (like nodes on a straight > street)? It would be also good to know, if the speed of rendering and > routing is a factor that should be concidered? I see now that in a few > places I added some unnecessary nodes - for example I should have moved > existing ones instead of adding new ones. Or perhaps I just looked at > those curves too long - with full zoom - and those jaggies grew up in my > mind to something bigger than they were :-) On the other hand, in many > places I think that I made good changes and not many nodes should have > been removed. > > I searched for information on this matter around the OSM web site and > mailing lists, and found this page (see the section "Accuracy": > http://wiki.openstreetmap.org/index.php/Editing_Standards_and_Conventions > I would seem to me that my edits were relatively close to the example > given there. > > I took some screenshots of the changes in question, so that people would > get a better picture of what I'm talking about. I took screenshots of > four different places that I edited, and three different versions of > each of them. The version one shows the situation before my edits, the > second one after my edits, and the third one after the removal of nodes > by the original editor. The screenshots are here: > http://www.flickr.com/photos/[EMAIL PROTECTED]/sets/72157604611934407/ > (note that for some reason Flickr shows the pictures in a reverse > alphabetical order). The zoomlevel used in the images is 16. > > It would be nice to get comments from people who know more about what's > involved. > I would just like to add to the other replies that before (re)moving nodes you should look at their properties. Sometimes they are at a specific place for a reason (bus stop, crossing, etc) Polyglot ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
la, 2008-04-19 kello 00:32 +0200, Frederik Ramm kirjoitti: > I think your edits are perfectly ok. Be reminded, though, that we have > automatic bezier curve hinting in place at least for the "[EMAIL PROTECTED]" > map, so it is very likely that the road was already a smooth curve on > the map even before you did your edits. Bezier hinting doesn't generally seem to work here in Finland yet. The roads that I edited were definitely unhinted, and all the neighbouring roads still are. I took a quick look at Helsinki (the capital) too, but it's rather jaggy there too. I found two ways here in Turku that apparently are hinted, but not more. I remember reading this bezier system being planned, but understood that it wouldn't be nearly ready yet. Is it indeed ready for use, and will it be the default method for rendering maps? Is it coming to Mapnik too? What about other renderers? If it will be used for all rendering in the future, that will make drawing nice curves much easier :-) Ari Torhamo ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
Ari, The short answer is that you can add as many nodes as you like if you think it better describes what is physically on the ground. I'm always adding nodes to stuff to make it look right, but I also remove nodes as I go where I know or find a feature is truly straight. Cheers Andy >-Original Message- >From: [EMAIL PROTECTED] [mailto:talk- >[EMAIL PROTECTED] On Behalf Of Ari Torhamo >Sent: 18 April 2008 10:22 PM >To: talk@openstreetmap.org >Subject: [OSM-talk] Too many nodes? > >Hello, > >I have a question regarding the amount of nodes that one may use to draw >a road, and whether the amount of nodes used has a considerable effect >on the speed of the OpenStreetMap. > >I did my first edits to OSM a few days ago. I'll get a GPS device soon, >but so far my only edits have been adding street names and making roads >more accurate by adding more nodes to curves, etc. Following these >edits, another person who has edited the same area earlier, contacted me >and told me not to add unnecessary nodes to roads that he has made long >time ago and added that he has already removed the unnecessary nodes. >According to him using many nodes slows down the rendering and routing. > >This made me wonder, what really is the right amount of nodes to use, >when one want's the curves to be right and look really nice, but not to >cause any problems by this. Can nodes be added as long as there are >visible jaggies on the rendered map - even small ones - and just leave >out the ones which have no affect on rendering (like nodes on a straight >street)? It would be also good to know, if the speed of rendering and >routing is a factor that should be concidered? I see now that in a few >places I added some unnecessary nodes - for example I should have moved >existing ones instead of adding new ones. Or perhaps I just looked at >those curves too long - with full zoom - and those jaggies grew up in my >mind to something bigger than they were :-) On the other hand, in many >places I think that I made good changes and not many nodes should have >been removed. > >I searched for information on this matter around the OSM web site and >mailing lists, and found this page (see the section "Accuracy": >http://wiki.openstreetmap.org/index.php/Editing_Standards_and_Conventions >I would seem to me that my edits were relatively close to the example >given there. > >I took some screenshots of the changes in question, so that people would >get a better picture of what I'm talking about. I took screenshots of >four different places that I edited, and three different versions of >each of them. The version one shows the situation before my edits, the >second one after my edits, and the third one after the removal of nodes >by the original editor. The screenshots are here: >http://www.flickr.com/photos/[EMAIL PROTECTED]/sets/72157604611934407/ >(note that for some reason Flickr shows the pictures in a reverse >alphabetical order). The zoomlevel used in the images is 16. > >It would be nice to get comments from people who know more about what's >involved. > > >Regards, > >Ari Torhamo > > >___ >talk mailing list >talk@openstreetmap.org >http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
Re: [OSM-talk] Too many nodes?
Hi, > I took some screenshots of the changes in question, so that people would > get a better picture of what I'm talking about. I took screenshots of > four different places that I edited, I think your edits are perfectly ok. Be reminded, though, that we have automatic bezier curve hinting in place at least for the "[EMAIL PROTECTED]" map, so it is very likely that the road was already a smooth curve on the map even before you did your edits. Bye Frederik -- Frederik Ramm ## eMail [EMAIL PROTECTED] ## N49°00'09" E008°23'33" ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
