Function: SETWCSBOX
Purpose: SETWCSBOX define a box inside/around a subset (No user
interaction)
Category: USER IO, PHYSICAL COORDINATES
File: ioutils.py
Author: M.G.R. Vogelaar
Use: boxtxt = "2h10m30s 60d32m2.7s D 2 arcmin 3 arcmin"
blo, bhi = gset.setwcsbox(boxtxt, checklimits=True)
gset Object of class Set for which a box should be defined.
boxtxt Box specification as a string
checklimits Boolean. If True, 'boxtxt' is not allowed to specify
regions beyond the data regions.
blo
bhi Two lists with coordinates which set the axes limits of
the input subset.
The coordinates are sorted so that 'blo' represents the
lower limits and 'bhi' the upper limits.
Note that also the Set object (gset) is updated.
Therefore you can retrieve the limits also by accessing
attributes gset.blo, gset.bhi
Description: Read also the description for the interactive routine WCSBOX
Notes: In most situations the conversion between grids and world
coordinates is independent of the subset. E.g. in a sequence
of channel maps, each RA,Dec image represents the same
coordinate system.
However, when we create subsets with only one spatial axis,
then the matching spatial coordinate depends on the selected
subset (e.g. with XV maps). Here we follow the implementation
in gdsbox.c. That is, only the first subset is used for
coordinate transformations.
Examples: boxtxt = "-10 -10 20 30"
boxtxt = "0 0 D 30 50"
boxtxt = "2h10m30s 60d32m2.7s D 10 10"
boxtxt = "2h10m30s 60d32m2.7s D 2 arcmin 3 arcmin"
blo, bhi = gset.setwcsbox(boxtxt)
Updates: Sep 28, 2012: VOG, Document created.