#!/usr/bin/env python3

import os
import grass.script as gscript

# settings
env = gscript.gisenv()
overwrite = True
env['GRASS_OVERWRITE'] = overwrite
env['GRASS_VERBOSE'] = False
env['GRASS_MESSAGE_FORMAT'] = 'standard'
gisdbase = env['GISDBASE']
location = env['LOCATION_NAME']
mapset = env['MAPSET']

# list rasters in mapset
raster_list = gscript.list_grouped('rast',
    pattern='shaded_relief_*')[mapset]

for raster in raster_list:
    # set region
    gscript.run_command(
        'g.region',
        raster=raster,
        res=0.1)
    # write map to image file
    gscript.run_command(
        'd.mon',
        start="cairo",
        width=1000,
        height=1000,
        output=os.path.join(
            gisdbase,
            location,
            raster+'.png'),
        overwrite=overwrite)
    gscript.run_command(
        'd.rast',
        map=raster)
    gscript.run_command(
        'd.mon',
        stop="cairo")