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

Torsten Mohr tmohr at s.netic.de
Tue May 12 06:30:52 BST 2009


Hello Juan,

thank you very very much !!

I just created the first map with the new ShapeFiles boundaries exactly on the
satellite images data.

At the moment i create a second, higher resolution map.


Thanks a lot,
Torsten.


Am Montag, 11. Mai 2009 23:32:14 schrieb Juan Lucas Dominguez Rubio:
> Hi. Your file world_boundaries_m.shp seems to be in the old-fashioned
> EPSG:3395 we discussed a few days ago.
>
> This should produce the shapefile you are looking for
> (world_boundaries_900913.shp):
>
> ogr2ogr -f "ESRI Shapefile" -s_srs epsg:3395 -t_srs "+proj=merc +a=6378137
> +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m
> +nadgrids=@null +no_defs +over" world_boundaries_900913.shp
> world_boundaries_m.shp
>
>
>
> regards
> Juan Lucas
>
>
>
> ________________________________
>
>
> 		Hello,
>
> 		thanks for taking a look at it.  The output is ~ 19000 lines, so i'll
> just show the top ~70 lines:
>
> 		Had to open data source read-only.
> 		INFO: Open of `world_boundaries_m.shp'
> 		      using driver `ESRI Shapefile' successful.
>
> 		Layer name: world_boundaries_m
> 		Geometry: Polygon
> 		Feature Count: 3807
> 		Extent: (-20037400.000000, -19929239.110000) - (20037400.000000,
> 		18375854.709643)
> 		Layer SRS WKT:
> 		PROJCS["Mercator",
> 		    GEOGCS["GCS_WGS_1984",
> 		        DATUM["WGS_1984",
> 		            SPHEROID["WGS_1984",6378137,298.257223563]],
> 		        PRIMEM["Greenwich",0],
> 		        UNIT["Degree",0.017453292519943295]],
> 		    PROJECTION["Mercator_1SP"],
> 		    PARAMETER["latitude_of_origin",0],
> 		    PARAMETER["central_meridian",0],
> 		    PARAMETER["scale_factor",1],
> 		    PARAMETER["false_easting",0],
> 		    PARAMETER["false_northing",0],
> 		    UNIT["Meter",1]]
> 		CAT: Real (16.0)
> 		FIPS_CNTRY: String (80.0)
> 		CNTRY_NAME: String (80.0)
> 		OGRFeature(world_boundaries_m):0
> 		  CAT (Real) =               15
> 		  FIPS_CNTRY (String) = AY
> 		  CNTRY_NAME (String) = Antarctica
>
> 		OGRFeature(world_boundaries_m):1
> 		  CAT (Real) =               15
> 		  FIPS_CNTRY (String) = AY
> 		  CNTRY_NAME (String) = Antarctica
>
> 		OGRFeature(world_boundaries_m):2
> 		  CAT (Real) =               15
> 		  FIPS_CNTRY (String) = AY
> 		  CNTRY_NAME (String) = Antarctica
>
> 		OGRFeature(world_boundaries_m):3
> 		  CAT (Real) =               15
> 		  FIPS_CNTRY (String) = AY
> 		  CNTRY_NAME (String) = Antarctica
>
> 		OGRFeature(world_boundaries_m):4
> 		  CAT (Real) =               15
> 		  FIPS_CNTRY (String) = AY
> 		  CNTRY_NAME (String) = Antarctica
>
> 		OGRFeature(world_boundaries_m):5
> 		  CAT (Real) =               15
> 		  FIPS_CNTRY (String) = AY
> 		  CNTRY_NAME (String) = Antarctica
>
> 		OGRFeature(world_boundaries_m):6
> 		  CAT (Real) =              174
> 		  FIPS_CNTRY (String) = NZ
> 		  CNTRY_NAME (String) = New Zealand
>
> 		OGRFeature(world_boundaries_m):7
> 		  CAT (Real) =              174
> 		  FIPS_CNTRY (String) = NZ
> 		  CNTRY_NAME (String) = New Zealand
>
> 		OGRFeature(world_boundaries_m):8
> 		  CAT (Real) =              174
> 		  FIPS_CNTRY (String) = NZ
> 		  CNTRY_NAME (String) = New Zealand
>
>
> 		It additionally tells me on stderr:
> 		ERROR 4: Unable to open world_boundaries_m.shp or world_boundaries_m.SHP.
>
>
> 		Thanks for any hints,
> 		Torsten.
>
> 		Am Montag, 11. Mai 2009 12:42:44 schrieb Juan Lucas Dominguez Rubio:
> 		> Hi:
> 		>
> 		> I'm curious about that shapefile that needs some stretching. Assuming
> 		> its name is filename.shp, try to type this:
> 		>
> 		> ogrinfo -geom=NO filename.shp filename
> 		>
> 		> what is the output?
> 		>
> 		> Regards,
> 		> Juan Lucas
> 		>
> 		>
> 		> ________________________________
> 		>
> 		>
> 		>
> 		>
> 		>               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
> 		>
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