[GRASS-dev] Re: windows binaries

[Michael Barton]

Moritz,

I looked at the script and you are indeed correct. I guess I'd forgotten
about this. Why is the PNG driver not available in wingrass when immediate
rendering works (AFAIK using the same underlying driver code and the PNG
driver)? I could rewrite d.vect.thematic as a TclTk module, but am reluctant
to do so because it would make it unavailable to people not using the TclTk
GUI--and make it more work to port to a new GUI platform.

I very much appreciate your efforts to start a C version. I won't be able to
advise you on coding, but might be able to offer some more general advice.

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

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


> From: Moritz Lennert <mlennert at club.worldonline.be>
> Date: Wed, 08 Nov 2006 16:05:14 +0100
> To: Michael Barton <michael.barton at asu.edu>
> Cc: Hamish <hamish_nospam at yahoo.com>, Paul Kelly
> <paul-grass at stjohnspoint.co.uk>, <grass-dev at grass.itc.it>
> Subject: Re: [GRASS-dev] Re: windows binaries
> 
> Michael Barton wrote:
>> Disclaimer: I only see a fragment of the entire post, and might
>> misunderstand.
>> 
>> D.vect.thematic does not require any particular driver. It uses d.vect
>> (iterated over different theme values) to render the final map.
>> 
>> This is why it can work with either an xmonitor or a TclTk canvas (the
>> latter via the PNG driver and immediate rendering mode.)
> 
> It won't work in immediate rendering mode since, as you say, it calls
> d.vect several times and in immediate rendering mode each call creates a
> new map from scratch, thus losing the overlaying of the different
> classes. This is why, in order to make it work with gis.m, it is (as far
> as I know) the only module using the PNG driver, and not immediate
> rendering. However, the PNG driver is not available in wingrass.
> 
>> D.vect.thematic should become a C-module like d.vect.chart. But since I
>> don't know C I simply wish.
> 
> It is high on my priority list as it will be a convincing argument for
> my colleagues if I can present them a nice module for thematic mapping.
> 
> Up to now, I was thinking neither in terms of ps.map, nor in terms of
> d.graph, but rather in terms of direct access to rendering. In my
> current understanding this means finding out how d.vect works in detail
> and applying that to d.vect.thematic.
> 
> But maybe using do_poly() and do_color() from d.graph might be another
> solution, but I will have to look at these in detail to understand.
> 
> I think I will try to quite quickly draw up a description of what I am
> aiming for and then ask y'all to advise me at how to do it.
> 
> Moritz
> 
>> 
>> 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: Wed, 8 Nov 2006 16:05:19 +1300
>>> To: Paul Kelly <paul-grass at stjohnspoint.co.uk>
>>> Cc: <grass-dev at grass.itc.it>
>>> Subject: Re: [GRASS-dev] Re: windows binaries
>>> 
>>> Paul Kelly wrote:
>>>> Didn't I read that d.vect.thematic needs the PNG driver to work. Have
>>>> to  confess that I'm not sure what it does - could it use ps.map?
>>> d.graph would be an easier path I think.
>>> 
>>> 
>>> Hamish
>>> 
>>> 
>> 
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>