[CF-metadata] Description of Map Projection Grid
davidf at dfanning.com
Fri Jan 22 10:49:53 MST 2010
I have searched the list archives, but have not found a solution to my problem.
I have map projected images I wish to package in a netCDF file. Along with
other map projection information, I would like to describe the extent of the
map projection grid that is associated with the image. This is an XY grid,
normally expressed in meters. Knowing the extent of this grid is important
for navigating the image, adding image annotations, and other things.
In GDAL the grid extent is sometimes expressed as the Northernmost_Northing,
the Southernmost_Northing, the Easternmost_Easting, and the
These names would mean something if my map projection was, for example,
a Mercator projection of the entire Earth. But my map projections are
and so this terminology is misleading, to say the least. If the image in is the
southern hemisphere, the terminology is bizarre.
What I am looking for are standard names to define the extent of this
XY grid. I have found in the CF 1.4 standard the names
and "projection_y_coordinate". This is getting to what I am looking
for, but there is no supporting documentation to tell me exactly which point
on my projection grid these names are describing. (I would guess this could
describe the upper-left corner of the grid, or what would be called
in a GeoTIFF file, for example, but I am not sure.)
Does anyone have any experience describing this XY grid? Or can anyone
suggest a standard name I have overlooked?
I think these names could be possibilities:
Thank you for your help.
David W. Fanning
NSIDC/CIRES, Univ. of Colorado
E-Mail: fanning at nsidc.org
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