[gdal-dev] SCH support in GDAL

[Agram, Piyush S (334D)]

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/7e8f3c56367689fd4048063a5d0e2cd15a
93293b



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