[OSM-talk] talk Digest, Vol 26, Issue 47

[Ed Davies]

Thomas Walraet wrote:
> Could we agree in a "normal direction" even if osmarender doesn't need 
> it at the moment ?
> i.e. : A closed area should be clockwise.
> 
> If all areas respect these constrain, it will allow correct rendering 
> even with partial areas.

Good suggestion.  Quite a lot of GIS and graphic software has this
sort of convention.  It does help a lot for partial areas and also
for making holes in the middle of areas.  E.g., with a clockwise
convention you know to always shade to the right of the line, even
when it's the outside of the area.  If your background shading is
land then sea (or lake) round an island is represented by an
anticlockwise coastline.

Ed.