[OSM-talk] "scale" a ShapeFile in Y-direction?

[Jukka Rahkonen]

Torsten Mohr <tmohr <at> s.netic.de> writes:

> 
> A ShapeFile contains the "source SRS" inside it, right?  When rendering
> world_boundaries_m and shoreline_300 i used the same "target SRS".
> But the result leads to different positions on the final map.

Not necessarily.  Shapefile is a collection of files with three compulsory
parts: .shp, .shx and .dbf.  Projection can be given with a .prj file but that
is optional and very often it is missing.  In that case the user just needs to
know or guess the correct projection.  If data are not to be reprojected or used
together with other data having different projection it is not necessary to know
the projection, but coordinates can just be taken as numbers as they are. That's
why .prj file is so often missing.  For data providers it would be an absolutely
good habbit to include .prj file always to all the shapefiles which are shipped
away.

-Jukka Rahkonen-