[GRASS-user] How to define the png image dimensions when using d.mon?

[jean pierre huart]

I launch a script without starting GRASS explicitly on an existing 
location, inspired by the solution proposed at 
https://grasswiki.osgeo.org/wiki/Working_with_GRASS_without_starting_it_explicitly.

I do not have any error in the logs, the image is created, but with 
default size (640x480) and white background.

I will try using the internal script console and give you a feed back if 
it works or not on my location/mapset.

Jean Pierre

On 09/03/16 17:08, Moritz Lennert wrote:
> On 09/03/16 16:55, jean pierre huart wrote:
>> Bingo! Thanks Moritz,
>>
>> - the existing file... I didn't care about it, convinced that the
>> --overwrite parameter will wipe it out.
>
> I agree that is a bit confusing (and could maybe be handled better), 
> but --overwrite comes into action at the time of writing of the file, 
> not at the time of reading the existing RENDER_FILE.
>
>> Launching this script in a cron, I've the feeling that the use of
>> GRASS_RENDER_IMMEDIATE is more appropriate. By the way, the choice is
>> simple, this solution works fine for me, but using d.mon does not.
>
> What does not work with d.mon ? Does my below script work for you (it 
> uses the NC demo data set [1]) ?
>
> Moritz
>
> [1] https://grass.osgeo.org/download/sample-data/
>
>
>>
>> Ciao
>>
>> On 09/03/16 16:12, Moritz Lennert wrote:
>>> On 09/03/16 15:39, jean pierre huart wrote:
>>>> Thanks Vinay, for the suggestion but I get an error on the d.out.file
>>>> instruction.
>>>> By the way, I've investigated the problem a bit further and found 
>>>> that I
>>>> mixed up instructions from manuals of different versions.
>>>> So coming back to GRASS v 7.0.x references I finally succeed in
>>>> obtaining a solution but not 100% satisfactory.
>>>>
>>>> First trial create a unique image combining raster and vector, but 
>>>> width
>>>> and height remains at default and background is not transparent:
>>>>
>>>>       os.environ['GRASS_RENDER_TRANSPARENT'] = 'TRUE'
>>>>       os.environ['GRASS_RENDER_WIDTH'] = str(1280)
>>>>       os.environ['GRASS_RENDER_HEIGHT'] = str(960)
>>>>       os.environ['GRASS_RENDER_FILE'] = filenameCombined.png
>>>>
>>>>       self.gscript.run_command('d.mon', overwrite=True, start='png',
>>>> output=filename)
>>>>       self.gscript.run_command('d.rast', map='{0}@{1}'.format(raster,
>>>> currentmapset)
>>>>       self.gscript.run_command('d.vect', map='{0}@{1}'.format(map,
>>>> currentmapset), color='white', fill_color='none')
>>>>       self.gscript.run_command('d.mon', stop="png")
>>>>
>>>>
>>>> Second trial successfull for obtaining desired width, height and
>>>> transparency of the background  but creating 2 images one for the 
>>>> raster
>>>> and the other for the vector, now I would like to combine them to have
>>>> only one image:
>>>>
>>>>       os.environ['GRASS_RENDER_IMMEDIATE'] = 'png'
>>>>       os.environ['GRASS_RENDER_TRANSPARENT'] = 'TRUE'
>>>>       os.environ['GRASS_RENDER_WIDTH'] = str(1280)
>>>>       os.environ['GRASS_RENDER_HEIGHT'] = str(960)
>>>>
>>>>       os.environ['GRASS_RENDER_FILE'] = filenameOfRaster.png
>>>>       self.gscript.run_command('d.rast', map='{0}@{1}'.format(raster,
>>>> currentmapset))
>>>>
>>>>       os.environ['GRASS_RENDER_FILE'] = filenameOfVector.png
>>>>       self.gscript.run_command('d.vect', map='{0}@{1}'.format(map,
>>>> currentmapset), color='white', fill_color='none')
>>>>
>>>> Modifying this with the following
>>>>
>>>>       os.environ['GRASS_RENDER_FILE'] = filenameCombined.png
>>>>       self.gscript.run_command('d.rast', map='{0}@{1}'.format(raster,
>>>> currentmapset))
>>>>       self.gscript.run_command('d.vect', map='{0}@{1}'.format(map,
>>>> currentmapset), color='white', fill_color='none')
>>>>
>>>> ends with only the image of the vector.
>>>>
>>>> I've the feeling that using d.mon would be preferable, but it seems 
>>>> that
>>>> it does not take into account the environment variables (at the
>>>> exception of GRASS_RENDER_FILE) that I propose.
>>>
>>> This script gives me differently sized png files with both maps
>>> displayed and transparent background:
>>>
>>> import grass.script as gscript
>>> import os
>>>
>>> os.environ['GRASS_RENDER_TRANSPARENT']='TRUE'
>>>
>>> for height in range(500,2000,500):
>>>      for width in range(500,2000,500):
>>>
>>>          os.system('rm map.png')
>>>          os.environ['GRASS_RENDER_HEIGHT']=str(height)
>>>          os.environ['GRASS_RENDER_WIDTH']=str(width)
>>>
>>>          gscript.run_command('d.mon', overwrite=True, start='png',
>>> output='map.png')
>>>          gscript.run_command('d.rast', map_='elevation')
>>>          gscript.run_command('d.vect', map_='roadsmajor')
>>>          gscript.run_command('d.mon', stop="png")
>>>
>>>          os.system('identify map.png')
>>>
>>>
>>> You can reach the same result with something like this:
>>>
>>> import grass.script as gscript
>>> import os
>>>
>>> os.environ['GRASS_RENDER_TRANSPARENT']='TRUE'
>>>
>>> for height in range(500,2000,500):
>>>      for width in range(500,2000,500):
>>>
>>>          os.system('rm map.png')
>>>          os.environ['GRASS_RENDER_IMMEDIATE']='png'
>>>          os.environ['GRASS_RENDER_FILE']='map.png'
>>>          os.environ['GRASS_RENDER_FILE_READ']='TRUE'
>>>          os.environ['GRASS_RENDER_HEIGHT']=str(height)
>>>          os.environ['GRASS_RENDER_WIDTH']=str(width)
>>>
>>>          gscript.run_command('d.rast', map_='elevation')
>>>          gscript.run_command('d.vect', map_='roadsmajor')
>>>
>>>          os.system('identify map.png')
>>>
>>>
>>> You might have to watch out for existing files. If a file already
>>> exists with the indicated name then GRASS cannot change its width and
>>> height.
>>>
>>> Hope this helps,
>>> Moritz
>>
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