[GRASS-dev] g.region: a possible extension to support multiple
zoom= and mode=intersect
Ivan Shmakov
ivan at theory.asu.ru
Tue Apr 1 14:44:05 EDT 2008
As `zoom=' somewhat mimics `rast=', wouldn't it be natural to
extend `zoom=' to allow multiple rasters?
Allowing multiple rasters for `zoom=' may make one wonder about
some further extensions. Firstly, wouldn't it be useful to
allow both `rast=' and `zoom=' be specified at the same time to
calculate the least region covering both the `rast=' and `zoom='
rasters (with the usual `rast=' and `zoom=' behaviour still
followed)? What about adding `vect=' and `region=' as well?
Secondly, the above extensions make it easy to compute set union
(or rather its boundary box) of the regions (specified as named
regions, rasters or vectors), but it seems to be useful to allow
one to calculate set intersection as well. Hence,
`mode=intersect' as a counterpart to the default `mode=union'
(or `mode=traditional'?)
Please note that the last change is somewhat disturbing to the
existing code, since the result of the intersection may well be
an empty region, while AFAIK there's no conception of empty
region in GRASS currently.
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