[OSM-talk] Mapnik name rendering problem case

David Earl david at frankieandshadow.com
Fri Aug 17 09:59:41 BST 2007


Probably one for Artem:

In this location on Mapnik...

http://www.openstreetmap.org/?lat=52.206067043510274&lon=0.11694516460297456&zoom=18&layers=B0F

the caption for Trinity Lane is upside down. I am preparing a map for 
publication and the proofreaders picked this up.

I think I see why: the southern arm points just a degree or two east of 
south, and the eastern branch just a degree or two south of east. I'm 
guessing you're looking at the southern arm, which on its own would have 
text with top to the right, but because it goes round the corner, it 
looks like it is the wrong way up.

Obviously there are cases that are unsolvable, like a W shape on its 
side, and I'm sure this case is hard. If, as I suspect, you are 
inspecting only one segment to determine direction, I wonder whether you 
could take all the segments into which the string will flow (which 
presumably you know) into account. You could average the angle perhaps, 
but maybe weight nearer horizontals more highly, as these have more 
influence on the reader than near verticals.

In the meantime, I'm going to run the way in the other direction, which 
I think will solve the problem for now.

David




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