[GRASS-dev] lib/vask

[Brad Douglas]

On Tue, 2006-06-20 at 09:12 +0100, Glynn Clements wrote:
> Hamish wrote:
> > > The selection of GCPs should probably be integrated with Michael's
> > > i.points replacement.
> > > 
> > > Is there any reason why other forms of interaction (other than visual
> > > selection of coordinates) would be necessary?
> > 
> > 
> > Beyond the mouse, keyboard entry is needed. e.g. set a GCP to where
> > lat/lon grid lines meet by marking "+" spot and keying in coordinates,
> > or getting GCPs coords by travelling to a landmark with a good GPS.
> 
> 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. Can that not be integrated with the i.points
> replacement?

Yes.  Yes, but might it have to be reimplemented for other modules?

> Essentially, to what extent is it possible to separate the entry of
> GCPs and other parameters from the actual rectification? Ideally, you
> want to have as much code as possible in a non-interactive core, with
> interaction limited to the outermost layer.

Getting GCPs is one step.  Rectification is another step (down the
line).  I would also expect to be able to input GCPs via file, also,
however rare it would be used.  I plan to implement the rectification
with GDAL, so one way or another, I'll have to get the GCPs into their
format.  The input and the "work" would be isolated.

How is v.digit going to be handled?  That has a similar situation.  If
we move solely to a command driven methodology, we won't be able to
digitize/edit [new] vector maps. :(

> > various [Confirm][Cancel] buttons are needed...
> 
> In most cases, it's preferable to execute operations without
> confirmation and to provide an undo feature for dealing with mistakes. 

Undo is definitely the way to go here.


-- 
Brad Douglas <rez touchofmadness com>                      KB8UYR
Address: 37.493,-121.924 / WGS84    National Map Corps #TNMC-3785