[GRASS-dev] lib/vask

[Hamish]

Glynn:
> Are you referring to entering one point with the mouse and the
> corresponding point as numerical coordinates? I can see why that would
> need to be interactive.

Yes.


Glynn:
> > In most cases, it's preferable to execute operations without
> > confirmation and to provide an undo feature for dealing with
> > mistakes. 
Brad:
> Undo is definitely the way to go here.

For entering GCPs precision and exactitude are much more important than
speed. Each point needs to be carefully checked and double checked.
And, at the risk of using a bad cliche, checked again. "Review &
confirm" is desired here, as well as delete (any) GCP and disable (any)
GCP. "Undo last point" seems like the knitting nightmares my mother used
to have undoing the whole row trying to get back to that dropped stitch.

But this is just the data-entry frontend [i.points] and nothing to do
with the non-interactive rectifying process [i.rectify] which happens
sometime after the digitizing sessions are done.


The tricky & important interactive task is the warped vector (or sampled
raster 50% alpha'd) overlay as-you-go. In i.vpoints this is in the
analyze menu, the code for it is there, but it doesn't seem to draw for
me (you supposedly can pick order=1,2,3 for that too). Having this
feature working would be a huge plus for GRASS. Esp. if merged with the
experimental auto-GCP code into a single i.uber_points.


Hamish