[GRASS-dev] lib/vask

[Michael Barton]

Hamish and others,

Please see below.

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton



> From: Hamish <hamish_nospam at yahoo.com>
> Date: Tue, 20 Jun 2006 23:48:16 +1200
> To: <rez at touchofmadness.com>
> Cc: <glynn at gclements.plus.com>, <werchowyna at epf.pl>, <grass-dev at grass.itc.it>
> Subject: Re: [GRASS-dev] lib/vask
> 
> 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.

Agreed.

> "Review &
> confirm" is desired here,

What does this actually mean in terms of the georectify process? Look at
individual and total RMS error and adjust GCP as needed?

> as well as delete (any) GCP and disable (any)
> GCP. 

Agreed. I've got this in the georectify module.

> "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.

For GCP create I don't understand the difference between undo and delete in
actual operation. I think you all are talking about the same thing. You
should be able to edit, disable, or delete GCP's

Maybe you mean if you edit a GCP, you can 'undo' to put the old coordinates
back? It is easier to add a new one and either disable (i.e., keep it so you
can see it and re-enable it if needed) or delete (get rid of it permanently)
the old one.

> 
> 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.

Is the analyze function the same in i.points and i.vpoints? If not, what is
the difference?

Thanks
Michael