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John,
On Tue, Jul 26, 2011 at 2:06 PM, John Caron <caron@xxxxxxxxxxxxxxxx> wrote:
>
> Im thinking the way forward for now might be to follow Chris' idea of
> specific examples. Then we can see what the real issues are.
>
> So Id invite anyone to submit examples, and we can work out the CDL.
>
This is an example for a four-band SAR image. As I mentioned earlier in the
discussion, all bands have the same wavelength but differ in polarization. I
am still trying to understand how I would define and reference the
individual bands in the proposed scheme.
netcdf alos_palsar_polarimetric_data {
dimensions:
band = 4;
xgrid = 1679 ;
ygrid = 2825 ;
time = 1 ;
variables:
char projection ;
:grid_mapping_name = "transverse_mercator" ;
:scale_factor_at_central_meridian = 0.9996 ;
:longitude_of_central_meridian = -69. ;
:latitude_of_projection_origin = 0. ;
:false_easting = 500000. ;
:false_northing = 10000000. ;
:projection_x_coordinate = "xgrid" ;
:projection_y_coordinate = "ygrid" ;
:units = "m" ;
:grid_boundary_top_projected_y = 8939000.938 ;
:grid_boundary_bottom_projected_y = 8868365.3795625 ;
:grid_boundary_right_projected_x = 628276.1252625 ;
:grid_boundary_left_projected_x = 586294.85 ;
:spatial_ref =
"PROJCS[\"WGS84_UTM_Zone_19S\",GEOGCS[\"GCS_WGS84\",DATUM[\"D_WGS84\",SPHEROID[\"WGS84\",6378137.0,298.25722014
]],PRIMEM[\"Greenwich\",0],UNIT[\"Degree\",0.017453292519943295]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"False_Easting\",500000.0],PARAMETER[\"False_Northing\",10000000.0],PARAMETER[\"Central_Meridian\",-69.0],PARAMETER[\"Scale_Factor\",0.9996],PARAMETER[\"Latitude_Of_Origin\",0.0],UNIT[\"Meter\",1]]"
;
:proj4text = "+proj=utm +zone=19 +south" ;
:zone = 19 ;
:semimajor_radius = 6378137. ;
:semiminor_radius = 6356752.314 ;
:GeoTransform = "586294.850000 25.003737 0 8939000.938000 0
-25.003737" ;
float image(band, time, ygrid, xgrid) ;
:coordinates = "polarization wavelength";
:FillValue = -999. ;
:long_name = "ALPSRP019116990" ;
:cell_methods = "area: backcatter value" ;
:units = "1" ;
:units_description = "unitless normalized radar cross-section" ;
:coordinates = "longitude latitude" ;
:grid_mapping = "projection" ;
float wavelength(band) ;
:coordinates = "band" ;
:units = "m" ;
:long_name = "center wavelength" ;
:standard_name = "radiation_center_wavelength" ;
char polarization(band) ;
:coordinates = "band" ;
:units = "1" ;
:long_name = "polarization" ;
:standard_name = "radiation_polarization" ;
float HH_AMPLITUDE_IMAGE(time, ygrid, xgrid) ; // band 1
float HV_AMPLITUDE_IMAGE(time, ygrid, xgrid) ; // band 2
float VH_AMPLITUDE_IMAGE(time, ygrid, xgrid) ; // band 3
float VV_AMPLITUDE_IMAGE(time, ygrid, xgrid) ; // band 4
float time(time) ;
:units = "seconds since 1900-01-01T00:00:00Z" ;
:references = "scene center time" ;
:standard_name = "time" ;
:axis = "T" ;
:long_name = "serial date" ;
float longitude(ygrid, xgrid) ;
:standard_name = "longitude" ;
:long_name = "longitude" ;
:units = "degrees_east" ;
:valid_range = -180., 180. ;
:FillValue = -999. ;
float latitude(ygrid, xgrid) ;
:standard_name = "latitude" ;
:long_name = "latitude" ;
:units = "degrees_north" ;
:valid_range = -90., 90. ;
:FillValue = -999. ;
float ygrid(ygrid) ;
:standard_name = "projection_y_coordinates" ;
:long_name = "projection_grid_y_centers" ;
:units = "meters" ;
:axis = "Y" ;
float xgrid(xgrid) ;
:standard_name = "projection_x_coordinates" ;
:long_name = "projection_grid_x_centers" ;
:units = "meters" ;
:axis = "X" ;
data:
wavelength = 0.2360571, 0.2360571, 0.2360571, 0.2360571 ;
polarization = "HH", "HV", "HV", "VV" ;
...
}
--
Best regards,
Rudi
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