[Gdal-dev] sterea projection

[Frank Warmerdam]

On 11/10/05, Jan Hartmann <j.l.h.hartmann at uva.nl> wrote:
> I built from CVS (version 1.3.1.0) and gdalwarp now accepts "sterea" as
> projection. However, the resulting raster is exactly the same as with
> "stere". Also, adding the "towgs" parameter doesn't change anything in
> both cases. The five calls:
>
> +proj=stere
> +proj=sterea
> +proj=stere +towgs84=..
> +proj=sterea +towgs84=..
> +init=epsg:28992
>
> produce exactly the same output.

Jan,

If I do "testepsg +init=28992" I now get a length report
including:

PROJ.4 rendering of [+init=epsg:28992] = +proj=sterea
+lat_0=52.15616055555555 +lon_0=5.38763888888889 +k=0.999908
+x_0=155000 +y_0=463000 +ellps=bessel +units=m +no_defs

Could you cd into gdal/ogr, do "make testepsg" and see if
you get the same results?  Also you might try:

 ident libgdal.so | grep srs_proj4

and verify you see:

warmerda at gdal2200[498]% ident libgdal.so | grep srs_proj4
     $Id: ogr_srs_proj4.cpp,v 1.58 2005/11/10 04:12:40 fwarmerdam Exp $

BTW, proj=stere on the commandline will now get mapped to
proj=sterea internally.  proj=stere* now maps to WKT definition
"Oblique_Stereographic" which in turn maps back to "proj=sterea".

Until there is some accepted other WKT name for the USGS
oblique stereographic, I don't really have a way of differentiating the
methods.  As noted before PROJ.4 strings on the GDAL commandline
will not necessary appear the same by the point they are passed to
PROJ.4.

I have taken the liberty of redirecting this back to gdal-dev since
I think some of the issues are broadly important.

Best regards,
--
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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