gdaltransform -s_srs EPSG:4326 -t_srs "+proj=aeqd +ellps=WGS84 +units=m
+wktext"
4.897 52.371
384537.462362467 5809944.80754693 0
echo 4.897 52.371 | proj +proj=aeqd +ellps=WGS84 +units=m
384923.72 5809986.5
I get the same result as GDAL (with proj 4.9.2)
$ echo 4.897 52.371 | proj +proj=aeqd +ellps=WGS84 +units=m
384537.46 5809944.81
gdaltransform -s_srs EPSG:4326 -t_srs "+proj=robin +ellps=WGS84 +units=m
+wktext"
4.897 52.371
394576.527707384 5570940.8420985 0
echo 4.897 52.371 | proj +proj=robin +ellps=WGS84 +units=m
394576.51 5571243.64
$ echo 4.897 52.371 | proj +proj=robin +ellps=WGS84 +units=m
394576.53 5570940.84
> Joaquim,
>
>> I'm implementing Proj.4 in GMT via GDAL and now, in the the testing
>> stage,
>>
>>
>>
>> I'm using data from
>>
>>
>>
>>
>>
>>
>>
>>
https://github.com/Beman/boost-trunk-git-svn/blob/master/libs/geometry/te
>> st_
>>
>>
>>
>> extensions/gis/projections/projections.cpp#L121
>>
>>
>>
>>
>>
>>
>>
>> but to my surprise lots of projections are not implemented in GDAL.
For
>>
>>
>>
>> example
>
> GDAL SRS model is based on WKT, so only projections that have a
mapping
> to WKT 1 (and for which a >developer cared enough to write the needed
> code !) are nominally supported
>
>> gdaltransform -s_srs EPSG:4326 -t_srs +proj=airy +ellps=WGS84
+units=m
>
> For unsupported projections, add +wktext. A dummy WKT representation
is
> then built that captures >the full proj.4 string in a EXTENSION node.
> Can also serve for supported projections if you want to >overrite the
> WKT -> proj.4 string conversion done by GDAL
>
>
>
>
>
>
> $ gdalsrsinfo "+proj=airy +ellps=WGS84 +units=m +wktext"
>
>
>
>
>
>
> PROJ.4 : +proj=airy +ellps=WGS84 +units=m +wktext
>
>
>
>
>
>
> OGC WKT :
>
>
>
> PROJCS["unnamed",
>
> GEOGCS["WGS 84",
>
> DATUM["unknown",
>
> SPHEROID["WGS84",6378137,298.257223563]],
>
> PRIMEM["Greenwich",0],
>
>
>
> UNIT["degree",0.0174532925199433]],
>
> PROJECTION["custom_proj4"],
>
>
>
> UNIT["Meter",1],
>
>
>
> EXTENSION["PROJ4","+proj=airy +ellps=WGS84 +units=m +wktext"]]
>
> $ gdaltransform -s_srs EPSG:4326 -t_srs "+proj=airy +ellps=WGS84
> +units=m +wktext"
>
>> ERROR 1: Translating source or target SRS failed:
>>
>>
>>
>> +proj=airy
>>
>>
>>
>>
>>
>>
>>
>> Or
>>
>>
>>
>>
>>
>>
>>
>> gdaltransform -s_srs EPSG:4326 -t_srs +proj=bonne
>>
>>
>>
>> ERROR 6: Failed to initialize PROJ.4 with `+proj=bonne +lon_0=0
+lat_1=0
>>
>>
>>
>> +x_0=0 +y_0=0 +ellps=WGS84 +units=m +no_defs'.
>
> I thing the issue is that lat_1=0 is invalid for bonne. Any non zero
> value is OK
>
>> Is there a place where I can find the list of available proj.4
>> transforms?
>
> You mean projections supported by GDAL (as far as I know, most if not
> all projections supported by >GDAL translate then to proj.4) ?
>
>
>
>
>
>
> Look at the various OSRSetXXXXX() methods in
>
>
>
> http://gdal.org/ogr__srs__api_8h.html
>
>
>
>
>
>
> Or starting there
>
>
>
>
https://github.com/OSGeo/gdal/blob/trunk/gdal/ogr/ogr_srs_proj4.cpp#L616
>
>> And also found some that do no agree between GDAL and proj. For
example
>>
>>
>>
>>
>>
>>
>>
>> echo 4.897 52.371 | proj +proj=vandg +ellps=WGS84 +units=m
>>
>>
>>
>> 489005.93 6431581.02
>>
>>
>>
>>
>>
>>
>>
>> gdaltransform -s_srs EPSG:4326 -t_srs "+proj=vandg +ellps=WGS84
>> +units=m"
>>
>>
>>
>> 4.897 52.371
>>
>>
>>
>> 488459.293282675 6424391.46347316 0
>
> If you add --debug on, you'll see that GDAL adds a +R_A parameter. I
> haven't dug up into history to >know the reason for that.
>
>
>
> If you add +wktext, the original string will be passed unmodified to
> proj.4
>
>
>
>
>
>
> Even
>
>
>
>
>
>
> --
>
>
> Spatialys - Geospatial professional services
>
>
>
> http://www.spatialys.com
--
Spatialys - Geospatial professional services
http://www.spatialys.com
