Geographic boundaries in GRASS raster/vector files

[Rich Shepard]

On Mon, 10 Apr 2000, Bill Brown - staff wrote:

> To be precise, it should be:
> 
>     north = max(y) + n-s res / 2.0
>     south = min(y) - n-s res / 2.0
>     west  = min(x) - e-w res / 2.0
>     east  = max(x) + e-w res / 2.0
> 
> if you are certain that the data profiles in your original data were used
> as boundaries.  Otherwise either your resolution or rows/cols won't match
> up.

Bill,

  Good point -- when the original data are in a raster format. Almost all of
our data (and the .e00/.shp/.mi(f,d)) are vector format. The corners are the
corners of the coverage area, not the center of the corner cells.

  I appreciate the reminder of the difference when translating points to the
GRASS edges.

Rich

Dr. Richard B. Shepard, President

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