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

[Torsten Mohr]

Hello Frederik,

thanks for your hint. Yes, i know about projections.  Actually, i reprojected
the rester images of "blue marble" from a form of WGS84 to Mercaator
with an own program.

But as i've heard it, world_boundaries_m is "defect".  But as an overlay
to represent the boundaries it would be ok.  If that information was a
misunderstanding and could be fixed with the right projection that would be
awesome.

If i use shoreline_300 instead, the projection is perfectly fine, but if you
try to render it _not_filled_ with a LineSymbolizer instead of a
PolygonSymbolizer, you get some disturbing "plates".  But the projection
is fine.

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.

Does that mean that world_boundaries_m is defect?

Is there a way to "fix" it somehow?  Or would scaling be possible?


Best regards,
Torsten.


> Hi,
>
> Torsten Mohr wrote:
> > I have a ShapeFile that seems to be incorrect, scaling it in Y-direction
> > could make it fit the background.
>
> Do you have a basic understanding of coordinate projections? If not,
> you'd be well advised to spend a few hours reading on the subject (start
> with Wikipedia, take it from there).
>
> You need to find out which projection your shapefile is in, and then set
> the correct one in your map file, and things are likely to work. Simply
> stretching the data from the shapefile is very unlikely to yield the
> desired results - you will probably find that the stretch factor that
> makes Iceland and the Equator fit will still have France out of place.
>
> Bye
> Frederik