[GRASSLIST:2151] Where's the data within a cell?

[Rich Shepard]

  In GRASS raster maps, where in a cell is the geographical location? Is it
in the center? The lower, left corner? The upper, left corner?

  This can certainly make a difference, especially when cell size is 30 m or
greater. It also matters when converting data from one format to another.
For example, when I wrote a program several years ago to convert ARC/Info
grid files to ASCII x, y, z files, I had to assume that the northing,
easting was in the lower, left corner because I could find nothing to tell
me differently. But, if GRASS holds the location in the center of the cell,
then such translated data could be off by 15 m. That's a lot, even for the
real world.

Thanks,

Rich

Dr. Richard B. Shepard, President

                       Applied Ecosystem Services, Inc. (TM)
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