[GRASS-user] Display output question

[Moritz Lennert]

On 18/02/09 16:09, Michael Barton wrote:
> 
> On Feb 18, 2009, at 7:55 AM, <grass-user-request at lists.osgeo.org> wrote:
> 
>> Date: Wed, 18 Feb 2009 11:40:43 +0100
>> From: Moritz Lennert <mlennert at club.worldonline.be>
>> Subject: Re: [GRASS-user] Display output question
>> To: grass-user at lists.osgeo.org
>> Message-ID: <499BE5AB.4060907 at club.worldonline.be>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> On 17/02/09 02:42, Michael Barton wrote:
>>>
>>>
>>> On Feb 16, 2009, at 6:34 PM, <grass-user-request at lists.osgeo.org> wrote:
>>>
>>>> Date: Tue, 17 Feb 2009 10:40:52 +1100
>>>> From: Richard Chirgwin <rchirgwin at ozemail.com.au>
>>>> Subject: [GRASS-user] Display output question
>>>> To: GRASS user list <grass-user at lists.osgeo.org>
>>>> Message-ID: <4999F984.9060605 at ozemail.com.au>
>>>> Content-Type: text/plain; charset=ISO-8859-1
>>>>
>>>> Hi all,
>>>>
>>>> What's the command-line equivalent to using the JPG export in the
>>>> display manager? (I would like to script outputs from a number of
>>>> workspace - GRC - files).
>>>>
>>>> Cheers,
>>>> Richard
>>>
>>> What happens in TclTk is that the display output is set to a PPM file
>>> instead of monitor. Then any d.* command creates a graphic file. The
>>> display graphic file is then converted to a jpeg. The latter can be done
>>> by a variety of programs, including gdal-translate.
>>>
>>> In wxPython, the display can be saved in a number of different formats
>>> using wxPython drivers.
>>
>>
>> Yes, but AFAIK, you cannot easily use the contents of a .grc or .gxw
>> file for scripting. You would have to parse the file with relevant tools
>> (awk, sed or an xml parser for gxw) and then apply these options to the
>> d.* commands using the cairo or PNG "monitor" to create a PNG file.
>>
>> In the TclTk GUI, you could save the content of the Output window after
>> having displayed your workspace and filter out the d.* commands. In the
>> wxGUI this is not possible anymore, AFAICT.
>>
>> It might be worth thinking about a module that translates workspace
>> files into d.* commands...
>>
>> Moritz
> 
> If you want to replicate a complex display with overlaying maps it is 
> more complicated than this even. The maps need to be composited. We use 
> g.pnmcomp. The input is a series of PNM maps and optionally their 
> transparency masks; the output is a single, composite PNM file. I 
> assumed (incorrectly perhaps?) that Richard was asking how to send a d.* 
> output to a file instead of a display. 

Well, if that's it, than it is very easy, and, as long as you don't need 
transparency, very easy, no need to mess with g.pnmcomp:

export GRASS_PNGFILE=mymap.png
export GRASS_RENDER_IMMEDIATE=TRUE
export GRASS_PNG_READ=TRUE

d.rast
d.vect
etc

Et voilà, your composite map is in mymap.png.

The difficult part is about "scripting the output of workspace files"...

Moritz