how to add support for other projections using proj.4
Added by Etienne Tourigny over 11 years ago
Hi,
I would like to know what work would be necessary to add a new projection type (e.g. spherical mercator) to remap from lat/lon, using the proj.4 library.
Currently, proj.4 is used to map from sinusoidal/lambert TO lat/lon. What is needed to do the reverse?
Regards,
Etienne
Replies (3)
RE: how to add support for other projections using proj.4 - Added by Joerg Trentmann over 11 years ago
Dear Etienne,
I am also looking for a convenient way to remap data from a regular lon/lat grid to a new projection (Lambert Azimuthal Equal Area in my case), which is supported by the proj4-library. Did you find a way using cdo to do such a transformation?
Thanks, regards,
Jörg
RE: how to add support for other projections using proj.4 - Added by Etienne Tourigny over 11 years ago
I haven't made any progress. My suggestion would be to use a tool like gdal to do the transformation.
i.e. gdalwarp -s_srs EPSG:4326 -t_srs '<proj_definition>' in.nc out.nc
it might work better if the file is first converted to gtiff and the result back to netcdf (or whatever else the file format is) using gdal_translate.
RE: how to add support for other projections using proj.4 - Added by Jaison-Thomas Ambadan over 11 years ago
Hi Jörg,
You could also use GMT tools such as "grdproject" http://gmt.soest.hawaii.edu/gmt/html/man/grdproject.html or "mapproject" http://gmt.soest.hawaii.edu/gmt/html/man/mapproject.html
"grdproject" can handle NetCDF files; here is an example to project a lon-lat grid to Lambert Azimuthal Equal-Area:
cdo -f nc -topo ifile.nc grdproject ifile.nc -Rg -Ja0/0/180/1:1 -Gofile.nc
Cheers,
J