zipped arcinfo grids

(zip rules. Now that a free version of zip/unzip is available for all platforms, we can forget about compress, gzip, and tar files.)

Portability of arc/info grid files is a problem. One choice is the arc/info export file, but it is extremely verbose.
Bil files are okay for integer grids with values from 0 to 32768, and no no_data.
In some cases, zipping up an entire workspace. is the simplest approach.

Sometimes, though, I just zip up the grid directory. This seems to violate the basic rule of arc/info: don't mess with arc/info data sets at the operating system prompt. Who cares? An arc/info grid consists of a directory with several weird files, plus two files--and an entry in a third file--in the info directory. The trick is to get arc/info to create those files in the info directory. If you download a zipped grid named, for example, northwest.zip, simply:

Go to an existing arc/info workspace
create a bogus grid, e.g.
- Grid: setwindow 0 0 1 1
- Grid: setcell 1
- Grid: northwest = 1
delete the new directory at the operating system level ("rm -r northwest", or whatever)
unzip northwest.zip to create a directory northwest.
arc/info should now see the imported grid.

zipped arcinfo grids