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

[jean pierre huart]

Bingo! Thanks Moritz,

- the existing file... I didn't care about it, convinced that the 
--overwrite parameter will wipe it out.
- os.environ['GRASS_RENDER_FILE_READ']='TRUE' to pile layers in one 
file, I thought it was only to import the first layer from an existing 
image.

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.

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