OpenStreetMap
I spent today walking around with a Nexus One and OSM Tracker for Android. It reported 2m accuracy in the open, and about 3 or 4m near buildings, which is quite good compared to my old Garmin GPS. I added many new amenities to White River Junction, plus a footpath and park.
Feeling more ambitious, I made a fairly major update to a hill and intersection on Route 5 that has seen massive construction work over the last few years. With any luck, OSM-based navigation software should now be able to substantially outperform Google Maps near this intersection, because it will know about the new roads and turn restrictions.
I relied on GPS tracks taken from the sidewalks on either side of the road, so there might be some occasional position and shape errors on the order of 5 to 10 feet.
토론
2010년 5월 1일 21:19에 mapsinE3님의 의견
Welcome to OSM.
An error of 5-10 feet really isn't significant at the current time.
As I am also new to OSM I 'd like to point you at this link, that is useful when you are learning how NOT to do it:
http://matt.dev.openstreetmap.org/dupe_nodes/about.html
Please check it out for your part of the world.
Looking at the above link I have learned that "ways" need to be "joined" or "merged", and not just have nodes superimposed or "put in the same place" with the editor of your choice.
If routing software is going to work with OSM, then we need to make sure that our local (high)ways are connected properly, with turn-restrictions and all.
Hope this helps a bit. Meanwhile have fun :)
2010년 5월 1일 22:18에 Lipperlandexpress님의 의견
Never thrust the displayed accuracy. The Nexus accuracy should not be better than the Garmin one under good reception conditions.
Modern GPS Chipsets are only better under difficult conditions
2010년 5월 1일 22:58에 ekidd님의 의견
@mapsinE3: Thank you for the pointer! There was only one duplicate node in my area of the map, and that was left over from an old import. It's fixed, now.
@Nightdive: Thank you for the tip! My Garmin showed considerably less consistency between multiple tracks in the same area than the Nexus One. I bought the Garmin off a clearance rack several years ago, and it typically claimed an accuracy of 20 ft under good conditions—and repeatedly walking the same track tended to show errors of at least that size.
The Nexus One, on the other hand, seems to have no more than half the error of the Garmin under reasonably favorable conditions. It makes some sense: It's a much newer GPS chipset, and it has a good reputation with the geocachers who've tried it. So it's _possible_ that I might be seeing an actual improvement. It's also possible that I'm imagining things. :-)
I'll walk some tracks repeatedly and superimpose, and see what I get.
2010년 5월 1일 22:59에 ekidd님의 의견
@mapsinE3: Thank you for the pointer! There was only one duplicate node in my area of the map, and that was left over from an old import. It's fixed, now.
@Nightdive: Thank you for the tip! My Garmin showed considerably less consistency between multiple tracks in the same area than the Nexus One. I bought the Garmin off a clearance rack several years ago, and it typically claimed an accuracy of 20 ft under good conditions—and repeatedly walking the same track tended to show errors of at least that size.
The Nexus One, on the other hand, seems to have no more than half the error of the Garmin under reasonably favorable conditions. It makes some sense: It's a much newer GPS chipset, and it has a good reputation with the geocachers who've tried it. So it's _possible_ that I might be seeing an actual improvement. It's also possible that I'm imagining things. :-)
I'll walk some tracks repeatedly and superimpose, and see what I get.