GMU WCS Server supports netCDF

• To: warmerdam@xxxxxxxxx
• Subject: GMU WCS Server supports netCDF
• From: Denis Nadeau <denis.nadeau@xxxxxxxxx>
• Date: Fri, 26 Aug 2005 18:01:07 -0400

Frank,

Netcdf now support UTM and LCC.
TM projection works fine with WCS data from NWGISS server .

I have checked for uniform grid spacing in projected values at three places

in the image:
left, middle and right
If I establish that spacing is uniform accross the map, I enable the
GeoTransform,
otherwise it stays disable.

But I need help with LCC metadata found in the test file RUC.nc.
I used osr.SetLCC1SP with STD_PARALLEL as dfScale. (Probably wrong...)
I just don't know what to do with these values for Lamber Conformal Conic :

standard_parallel=3D25
longitude_of_central_meridian=3D-95
latitude_of_projection_origin=3D25
GRIB_earth_shape=3Dspherical
GRIB_earth_shape_code=3D0

You can see that False_Easting an False_Northing are missing so, I set them

to 0 which is probably wrong too.

Finallly, for latitude/longitude data, I use WKT "WGS84".
(I also check for uniform grid spacing as before ...)

Regards,
Denis


2005/8/26, Frank Warmerdam <fwarmerdam@xxxxxxxxx>:

Denis,

The GMU WCS NetCDF file now reports:

Coordinate System is `'
Origin =3D (94.692708,6.738066)
Pixel Size =3D (0.00271231,-0.00268426)

Corner Coordinates:
Upper Left ( 94.6927079, 6.7380663)
Lower Left ( 94.6927079, 4.8295543)
Upper Right ( 96.8978175, 6.7380663)
Lower Right ( 96.8978175, 4.8295543)
Center ( 95.7952627, 5.7838103)

But, I am not sure how this could be. The file is apparently
projected in transverse mercator, but those are lat/long values.
The file presumably is not projected in lat/long so the lat/long
pixel size will not be consistent across the image. It is important
we only set the geotransform based on the lat/lon (or projected values)
if we can establish that the pixel spacing is uniform across the
dimension maps.

In this file, we should be picking up the TM values from the xdim and
ydim arrays.

... phone call from you ...

Well, I think we have covered this mostly on the phone now, but i'll
send what I had in the email so far.