[GRASS-dev] Re: [GRASS-user] GRASS "custom" applications

[Glynn Clements]

Thomas Adams wrote:

> Thanks for taking the time for the thoughtful responses. I very much 
> want to contribute $(G!7(B and I think I can $(G!7(B it's more a matter of finding 
> the time (as I'm sure it's true for you and others). I don't know 
> Tcl/Tk, but I'm sure I could mess around and do OK (I do my programming 
> in Perl & C mostly, but also *some* simple shell scripting). My 
> programming background includes X Window System & Motif$B!D(B

For GUI code, we normally use interpreted languages. Previous GUIs
(tcltkgrass, d.m, gis.m) used Tcl/Tk, the next one will use wxPython.

Mostly, we try to avoid doing "real work" in the GUI. Instead, GUI
actions invoke external commands which generate images which are then
displayed by the GUI.

This has the advantage of limiting the amount of code which is "tied"
to the GUI. E.g. if you wanted a web-based interface, all of the
external commands which the GUI uses can be called just as easily from
a CGI script.

> However, I have been involved with the U.S. National Weather Services' 
> effort to develop some policy about GIS use in our operational systems. 
> ArcGIS, for example, does not fit very well for a couple of reasons: (1) 
> cost and (2) we use Linux and want to stay open source. So, it *looks* 
> like the recommendation to baseline GRASS (and other open source GIS & 
> related tools - GMT, R, Mapserver, PostGIS, etc.) into our systems may 
> actually occur. I have been pretty instrumental in carrying the banner 
> for GRASS in this. What this means, is that now I have to answer some 
> questions that relate to the questions I have been asking. There are a 
> lot of very competent programmers in the NWS who could help tremendously 
> (there are also a lot of novice computer users as well); but, it's 
> falling on my shoulders to demonstrate a couple 'custom applications' 
> that duplicate what is already being done in ArcGIS 9.x and ArcView.
> 
> I have no doubts that the customizations can be done; I just want to do 
> it the most sensible way, that minimizes how much work I have to do and 
> that I can show to others in the NWS how easy it is to customize GRASS. 
> I really like the GRASS extension manager approach by Benjamin Ducke. I 

In some respects, this might be a bad time for that. The existing GUI
is planned to be replaced, but its replacement is really still at an
"alpha" stage.

Conversely, if you want to help out, generic GUI programming
experience is probably more useful than specific knowledge of the
code. Development of the new GUI is still at a early enough stage that
nothing is set in stone yet.

-- 
Glynn Clements <glynn at gclements.plus.com>