AIPS HELP file for DOALIGN in 31DEC09

As of Sun Nov 22 16:34:07 2009

HELP SECTION

DOALIGN
Type:  Adverb (Logical)
Use:   Controls how two or more maps are aligned by various
       tasks.  If DOALIGN positive (actually >= 0.1), then the
       images are aligned by their coordinates and are required
       to have the same axis increments, types, and rotations.
       If DOALIGN is zero (actually -0.1 < DOALIGN < 0.1), then
       the images are aligned by their coordinates at the bottom
       left corner (computed linearly without regard for
       rotation), but no other tests are made.  If DOALIGN is -1
       (actually <= -0.1 and >= -1.5), then the images are
       aligned by offset from their reference pixels and no axis
       parameter tests are made.  If DOALIGN = -2 (actually <
       -1.5), the images are aligned at pixel (1,1,...) and the
       headers are ignored --- which can lead to bad output
       headers of course.
Null value:  true (1).
Tasks:
  BLANK.......Blanks regions of an image using the TV or another
              image.
  BLSUM.......Sums images over irregular regions.
  COMB........Combine two images in various ways.
  CORMS.......Combine two images in various ways with error
              images available.
  GREYS.......Grey-scale plot with overlayed contours.
  PCNTR.......Contour plot with overlayed polarization vectors.

EXPLAIN SECTION