[OSM-newbies] right angles and similar fine detail in Potlatch

[Ed Hillsman]

I'm mapping a university campus where a lot of the buildings have  
various right-angled features. The building at the center of this

http://www.openstreetmap.org/?lat=28.061312&lon=-82.410209&zoom=18&layers=B000FTF

is an example. If you look closely, or view it in Potlatch and zoom  
in, you will see that most of the angles are not right angles. I have  
edited them in Potlatch so that they are right angles, and saved them,  
only to find that when the tile has been updated, or when I view them  
again in Potlatch, the corners have reverted to their out-of-square  
positions. Sometimes this reversion happens during the Potlatch  
session, sometimes not. It is as if Potlatch has a snap-to-grid  
feature, but I can't find discussion of such a feature. Or maybe it's  
just not designed to edit at this fine level of detail. I sometimes  
have similar problems with curved ways as well, where one point will  
not stay in the proper position for a smooth curve. I've checked  
various OSM list archives but haven't been able to find any discussion  
of the problem, probably because I haven't framed the search well  
enough.

Can anyone suggest a way to get the building to stay squared up? I  
know that at low zoom levels, it doesn't make much difference, but we  
are developing an application for disabled students who will use it at  
high zoom levels, and fidelity to building shapes will help with our  
credibility. Thanks in advance for any suggestions you can offer.

Ed



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/newbies/attachments/20091121/4bf9473e/attachment.html>