[gdal-dev] SCH support in GDAL

[Even Rouault]

Le lundi 04 janvier 2016 18:48:16, Agram, Piyush S (334D) a écrit :
> Hi,
>   Currently, there are no raster formats that use this projection method.
> These are more likely to be used with GCP's or in metadata. But in the
> future, these could be used with raster formats - e.g, JPL's UAVSAR data.
> 
> Are there other parts of GDAL where support for the new projection needs
> to be included, if assuming, some raster format needed to use it?

Some drivers have a very dedicated way of expression projections, think of 
GeoTIFF, so there will be no way to represent SCH for them (unless the 
underlying format is extended to include SCH). So currently this will only 
work with drivers that store proj.4 strings or WKT strings.

I've committed your PR to trunk (with a fix so that Validate() works, and a one 
line test case in autotest/osr/osr_proj4.py)


> 
> Thanks
> Piyush
> 
> On 1/4/16 3:58 AM, "Even Rouault" <even.rouault at spatialys.com> wrote:
> >Le dimanche 03 janvier 2016 00:54:41, Agram, Piyush S (334D) a écrit :
> >> Hi,
> >> 
> >>    Spherical Cross-track Height (SCH) coordinate system support was
> >>
> >>added
> >>
> >> to PROJ.4 about a couple of months ago. This is widely used for
> >>
> >>processing
> >>
> >> radar remote sensing data, particularly for the NASA radar missions. I
> >> have tried to include support for this coordinate system in GDAL by
> >> defining new OGR SRS parameters.
> >>
> >> You can find the change log here:
> >>https://github.com/piyushrpt/gdal/commit/7e8f3c56367689fd4048063a5d0e2cd1
> >>5a
> >>
> >> 93293b
> >
> >Technically looks good to me. Just for our information: are there raster
> >formats handled by GDAL that will make use of this projection method ?
> >
> >> Example output of gdalsrsinfo look's like this:
> >> > gdalsrsinfo "+proj=sch +plat_0=30.3 +plon_0=45.1 +phdg_0=-12.2
> >> >
> >> >+datum=WGS84"
> >> 
> >> PROJ.4 : '+proj=sch +plat_0=30.3 +plon_0=45.1 +phdg_0=-12.2 +h_0=0
> >> +datum=WGS84 +units=m +no_defs '
> >> 
> >> OGC WKT :
> >> PROJCS["unnamed",
> >> 
> >> 	GEOGCS["WGS 84",
> >> 	
> >> 		DATUM["WGS_1984",
> >> 		
> >> 			SPHEROID["WGS 84",6378137,298.257223563,
> >> 			
> >> 				AUTHORITY["EPSG","7030"]],
> >> 			
> >> 			AUTHORITY["EPSG","6326"]],
> >> 		
> >> 		PRIMEM["Greenwich",0,
> >> 		
> >> 			AUTHORITY["EPSG","8901"]],
> >> 		
> >> 		UNIT["degree",0.0174532925199433,
> >> 		
> >> 			AUTHORITY["EPSG","9122"]],
> >> 		
> >> 		AUTHORITY["EPSG","4326"]],
> >> 	
> >> 	PROJECTION["Spherical_Cross_Track_Height"],
> >> 	PARAMETER["peg_point_latitude",30.3],
> >> 	PARAMETER["peg_point_longitude",45.1],
> >> 	PARAMETER["peg_point_heading",-12.2],
> >> 	PARAMETER["peg_point_height",0]]
> >> 
> >> This is my first time working with OGR parameters. Any comments/
> >> suggestions for improvements are welcome.
> >> I hope to issue a pull request once the changes conform with established
> >> conventions.
> >> 
> >> Thanks
> >> Piyush
> >> 
> >> _______________________________________________
> >> gdal-dev mailing list
> >> gdal-dev at lists.osgeo.org
> >> http://lists.osgeo.org/mailman/listinfo/gdal-dev
> 
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