Re: [talk-au] Uploading traces (Was; Hi all ...)
--- On Thu, 18/6/09, Ross Scanlon i...@4x4falcon.com wrote: * improving routing information, by working out average speed on roads (at different times). If your connected to the internet that's fine but it's no use for on the road re-routing, unless you have all the gps traces downloaded to your gps. This should be tagged by maxspeed anyway. I found an example of where this information would be useful. Dirt/unpaved roads are generally 100km/hr max speed. However this isn't usually the best speed to be traveling on them, but getting the average speed everyone does and being able to give approximation warnings of sharp bends that may or may not be signed properly by the local council due to it usually being general knowledge for people that travel on those roads. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
On Thu, 2009-06-18 at 15:25 +1000, Ross Scanlon wrote: * improving routing information, by working out average speed on roads (at different times). If your connected to the internet that's fine but it's no use for on the road re-routing, unless you have all the gps traces downloaded to your gps. This should be tagged by maxspeed anyway. Maximum speed is different to expected speed. What I'm talking about is the ability to work out which road is generally the best at a certain time. For example, I know if I use the highway at 8, it is clogged with people going to work, but if I use the alternative route a bit later, then it is clogged with school parents. This sort of data is mostly static (when you consider enough dimensions), and unrelated to maximum speed. Some one may have also driven the road really slowly (push bike) and some one may have done it at the speed limit. This would skew any reliability. Hence the need for lots of data. All the algorithms that do this stuff are designed knowing that there will be noisy data. Google has their own version of something like this, except real time. They attach gps transmitters to some taxis and have sensors on roads, and bring all that information in to try to work out what the average speed is on different roads. If a taxi is parked, or a road sensor is busted, it doesn't freak out and declare that the average speed is 0. * improving height maps, by taking (lots of) samples where altitude information was present. Pointless, vertical data is grossly out from a gps you are better off using the NASA dem data. You can still find out useful things from noisy data, as long as there is enough of it that you can filter out the noise, and since we already have a starting point for the data, we can be even smarter. Throwing more information at the problem helps us get a better solution - even if some of the information is noisy. * automatically guessing the number of lanes on a road, by looking at the variance of traces over sections in each direction. Should be tagged anyway (when more than 1) and how do you know it's not an accuracy problem. re accuracy problem: same answer as before. re should be tagged anyway: that may be true, but they often aren't. If an automatic process can fix up most of them, then it saves us time. And if we revisit the tagging later to make it more expressive (e.g. saying which specific lanes end), then this will save a lot of time. I was going to say look at the sat photo but that dosn't help as its covered over with trees. We have to trust that osm's are putting in accurate data but from what I've seen the data already there is miles better than google maps particularly in rural Australia. Absolutely (and I only checked because it isn't too far out of my way). But, if someone has the time to do cool things with the gps traces, then they will be very thankful for any more data. I know of one person who uses the raw gpx traces from OSM to improve the accuracy of another gps (it tries to model the walking patterns of a person, so it can predict how their speed will change as they turn corners and stuff like that). I don't know a whole lot about it, but this person was begging me for my gpx traces because he wanted even more data... so obviously there are some uses for it :) Just to reiterate - I don't personally care if you do upload or not. But if you are holding back from uploading because you think it isn't useful, then I'd disagree. Andy ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
Secondly, come the day when MegaMap Inc, decide to sue OSM, due to a part of the map looking suspiciously derived from MegaMap's products, the existance of GPS traces in OSM may assist greatly in defending against that threat. Also a good reason to use simplified gpx tracks from JOSM as then the points are exactly as the gpx track point not a traced/modified position. -- Cheers Ross ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
--- On Wed, 17/6/09, Ross Scanlon i...@4x4falcon.com wrote: Generally it was directed at the comment should upload , made without anything to back it up and also rhetorical. Just because some think they should be uploaded does not mean everyone wants, or has, to. Should doesn't mean the same thing as must, I didn't say you must upload, I said you should (for the greater good). No kidding, I'm well aware of the difference betweend should and must. You did not say anything about the greater good and I've yet to see any reason that it is for the greater good. Arguments over being able to create a more accurate map when we are talking sub 2m distances in most cases are irrelevant. That's the distance between one gps and the other on one of my vehicles and not even the width of most roads. -- Cheers Ross ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
--- On Wed, 17/6/09, Ross Scanlon i...@4x4falcon.com wrote: No kidding, I'm well aware of the difference betweend should and must. You keep implying must when I've said should. You did not say anything about the greater good and I've yet to see any reason that it is for the greater good. Ummm if it isn't for the greater good, why else are we bothering to supply data and support OSM in various ways? I don't get any personal benefit at present using OSM derived maps in most places I'm likely to be and it might be a long time until I do. Yes I realise I've just made another very subjective statement and people in other areas will be able to benefit as is, but I'm trying to make a point about the philisphopical nature of the beast as much as any practical one. Arguments over being able to create a more accurate map when we are talking sub 2m distances in most cases are irrelevant. That's the distance between one gps and the other on one of my vehicles and not even the width of most roads. Unless you have better than consumer grade kit you won't be consistently getting within 2m of accuracy all the time, and I think that sums the argument up right there, you're assuming you will. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
--- On Wed, 17/6/09, Delta Foxtrot delta_foxt...@yahoo.com wrote: Unless you have better than consumer grade kit you won't be consistently getting within 2m of accuracy all the time, and I think that sums the argument up right there, you're assuming you will. Let me re-phrase... The main reason I think uploading GPX files is important is so we can average all the data available and get within 1 to 2m accuracy. At this point in time there is no way possible that everyone will actually be getting 2m or better of accuracy all the time unless they have better than currently available consumer grade kit. Secondly, and I hadn't really considered this possibility but it could be more important given the right circumstance, is so that it can be used as evidence on how the map was derived. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
--- On Wed, 17/6/09, Ross Scanlon i...@4x4falcon.com wrote: No kidding, I'm well aware of the difference betweend should and must. You keep implying must when I've said should. No i'm not implying must. I asked why SHOULD we be uploading them. You did not say anything about the greater good and I've yet to see any reason that it is for the greater good. Ummm if it isn't for the greater good, why else are we bothering to supply data and support OSM in various ways? The greater good is supported by the end product not by data (GPX files) that, although supports the end product, is not shown in the final map or routing solutions. I don't get any personal benefit at present using OSM derived maps in most places I'm likely to be and it might be a long time until I do. Yes I realise I've just made another very subjective statement and people in other areas will be able to benefit as is, but I'm trying to make a point about the philisphopical nature of the beast as much as any practical one. Do any of us? I've put in about 12000km's of ways and yes I'm getting more benefit daily but there are still places without osm data and if I'm going there I'll add data from them. Arguments over being able to create a more accurate map when we are talking sub 2m distances in most cases are irrelevant. That's the distance between one gps and the other on one of my vehicles and not even the width of most roads. Unless you have better than consumer grade kit you won't be consistently getting within 2m of accuracy all the time, and I think that sums the argument up right there, you're assuming you will. And yet again you are assuming I'm saying something totally different to what I'm saying. What I'm refering to is when there are multiple traces all less than 2m apart IN MOST CASES not the accuracy of the gps. Who said I don't have better than consumer grade equipment? Most consumer grade will be less than 5m but generally arround 10m depending on particular hardware used but that's a matter of checking the HDOP at the time. At no point did I say anything about getting 2m accuracy from consumer grade equipment. -- Cheers Ross ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
--- On Wed, 17/6/09, Ross Scanlon i...@4x4falcon.com wrote: The greater good is supported by the end product not by data (GPX files) that, although supports the end product, is not shown in the final map or routing solutions. We were always told to show our working out in school for a reason, to prove we knew how to derive the answer, and if not to show where we went wrong, otherwise you can only make assumptions about the final product without any certainty of how you came to that conclusion. And yet again you are assuming I'm saying something totally different to what I'm saying. What I'm refering to is when there are multiple traces all less than 2m apart IN MOST CASES not the accuracy of the gps. Who said I don't have better than consumer grade equipment? Which is why I refined my answer in further emails, if someone does have better than consumer grade kit it's all the more reason for it to end up in the OSM database to give better averages, rather than have them skewed by less accurate equipment because of assumptions made by those committing changes without showing their working out. Most consumer grade will be less than 5m but generally arround 10m depending on particular hardware used but that's a matter of checking the HDOP at the time. At no point did I say anything GPS chips don't always get HDOP accurate, or they lie. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
If the data was challenged that I entered then osm can contact me for the original data. In the meantime why are we filling up storage on osm with data that is not producing the final product ie the map. Why do I need to challenge you to prove what you did was correct, if the GPX information is present and downloaded into say JOSM I can see if you did a good job or not, otherwise I am left guessing based on the data other people provided. I did not say you were challenging me. I'm talking about the final product being challenged by MegaMap Inc and osm being able to show where the data came from. osm if necessary could then obtain that data from me, the history of the origin of the data is in the database. No, if someone had better than consumer grade equipment then that should How do I take your word on that if you haven't proven yourself to be honest in this matter and shown your working out? How do I take your word for it when you use an anonymous mail address and don't sign your name to any email. be uploaded and locked so that it can not be changed except by the person uploading the data or on request to them. It would override the consumer grade equipment totally. Yes, people always tell the truth all the time, but that doesn't prove anything. I never said that users with better than consumer grade equipment should have an automatic right to this. There would of course have to be some sort of confirmation of capability by osm. What I am saying is that if known high quality data is available don't degrade it by averaging with known low quality data. But they are very rarely (less than once a year) wrong. News to me, I've had several devices with various brands of GPS chips in them and they will say for example 8m accuracy and be out by 100m at times. I especially noticed this since I started embedding OSM maps into an app I'm coding and the GPS accuracy will be within a reasonable tolerance, but the plot on the map will be all over the place. Hdop is not an indication of distance it is an indication of the confidence of the accuracy of the position and it is not readily translated to distance. So if you had an hdop of 8 then I would expect the position to be very inaccurate. -- Cheers Ross ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
--- On Thu, 18/6/09, Ross Scanlon i...@4x4falcon.com wrote: How do I take your word for it when you use an anonymous mail address and don't sign your name to any email. Just because you used a less common alias, how do I even know the name you supply is true? In reality it doesn't actually matter, trust is a fluid concept that changes shape over time based on past experiences and most importantly what you can prove. Without proof all we have is the word of someone with an assumed name and a semi-anonymous email account. I could have gone to a lot more trouble if I really wanted to, but you get the idea of where this is heading. I never said that users with better than consumer grade equipment should have an automatic right to this. There would of course have to be some sort of confirmation of capability by osm. You mean like proof? :) Also just because they have access to better equipment, do they exclusively only use that equipment? How often is it calibrated? Do they have suitable qualifications to make statements of fact regarding the information they provide? What I am saying is that if known high quality data is available don't degrade it by averaging with known low quality data. I agree, but it's a safe assumption 95+% of the data supplied to OSM isn't high quality GPS data and for those sections covered by the lower quality data averaging would be useful. Hdop is not an indication of distance it is an indication of the confidence of the accuracy of the position and it is not readily translated to distance. So if you had an hdop of 8 then I would expect the position to be very inaccurate. I agree with you about being a confidence rating, however everything seems to treat this guesstimate of accuracy in terms of this answer is right within a possibility of say 24 metres. From all the documentation I've seen, HDOP is treated as the accuracy divided by 6, so if the chip estimates within 24m, the HDOP will be 4. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
* improving routing information, by working out average speed on roads (at different times). If your connected to the internet that's fine but it's no use for on the road re-routing, unless you have all the gps traces downloaded to your gps. This should be tagged by maxspeed anyway. Some one may have also driven the road really slowly (push bike) and some one may have done it at the speed limit. This would skew any reliability. * improving height maps, by taking (lots of) samples where altitude information was present. Pointless, vertical data is grossly out from a gps you are better off using the NASA dem data. * automatically guessing the number of lanes on a road, by looking at the variance of traces over sections in each direction. Should be tagged anyway (when more than 1) and how do you know it's not an accuracy problem. * automatically marking ways which haven't been looked at for a long time, so someone can revisit them to make sure they haven't changed. A good idea. * (insert your imagination here) If we had a trace here showing a person getting to a dead end, turning around and going back around the other way, then it would be much more convincing that the OSM data is correct. As it is, it is our word against google's. I was going to say look at the sat photo but that dosn't help as its covered over with trees. We have to trust that osm's are putting in accurate data but from what I've seen the data already there is miles better than google maps particularly in rural Australia. -- Cheers Ross ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
Re: [talk-au] Uploading traces (Was; Hi all ...)
--- On Thu, 18/6/09, Ross Scanlon i...@4x4falcon.com wrote: We have to trust that osm's are putting in accurate data but from what I've seen the data already there is miles better than google maps particularly in rural Australia. The benefit of collecting fresh data, so knowing rought times between collections is probably important here, I often see mistakes on google maps that has to be from ancient data sources that have never been updated since. Also the train lines on gmaps follow ABS like paths in places where the line has been straightened, but the mapping data hasn't. ___ Talk-au mailing list Talk-au@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-au
