[OSM-talk] How to perfect the map

[Chris Hill]

I have tried to draw large buildings by walking around them.  This has problems due to access and problems due to losing the GPS signal in the signal shadow (canyoning). If you repeat this on different days the average sometimes helps but the building has to be large to not be swamped by the GPS inaccuracy - maybe Galileo will help in 4 or five years' time.

I have also drawn a large, prominent warehouse by standing in line with a side, standing back many hundred metres and marking the point, repeating this at both ends of the each side (for a rectangular building you get 8 points in total) you can then join these up in JOSM as guide lines, drawing the building where the lines cross and delete the guidelines - you need to load the GPX file directly into JOSM to see the waypoints.  This is also crude for a building, but for a large area that you can't gain full access to (such as a large industrial area) it can help.  Lots and lots of photos help a lot too.  

The best way overall is to trace the aerial photos and probably the only way for buildings with a complex shape, but in the area I'm interested in Yahoo! are low-res and not much use for fine detail.


cheers, Chris

----- Original Message ----
> From: Lars Aronsson <lars at aronsson..se>
> To: talk at openstreetmap.org
> Sent: Sunday, 23 March, 2008 10:47:10 AM
> Subject: [OSM-talk] How to perfect the map
> 
[snip]

> All the wiki pages on "map features" describe how to add 
> denomination to an amenity=place_of_worship, but don't say when 
> a church should be drawn as a dot amenity or when the outlines of 
> the building (and surrounding park) should be mapped in detail. I 
> think we should make wiki pages that start with real world objects 
> instead of tags.
> 
> Is there any written description for that kind of detailed 
> mapping?
> 
> Do you print out the OpenStreetMap at zoom=17 of a few city blocks 
> and bring it with you to check all the details?  Or can you run 
> JOSM on a PDA while walking around?
> 






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