def export_png_in_projection(src_mapset_name, map_name, output_file,
epsg_code,
routpng_flags, compression, wgs84_file,
use_region=True):
"""
:param use_region: use computation region and not map extent
"""
if use_region:
src_region = get_region()
src_proj_string = get_location_proj_string()
# TODO: change only location and not gisdbase?
# we rely on the tmp dir having enough space for our map
tgt_gisdbase = tempfile.mkdtemp()
# this is not needed if we use mkdtemp but why not
tgt_location = 'r.out.png.proj_location_%s' % epsg_code
# because we are using PERMANENT we don't have to create mapset explicitly
tgt_mapset_name = 'PERMANENT'
src_mapset = Mapset(src_mapset_name)
# get source (old) and set target (new) GISRC enviromental variable
# TODO: set environ only for child processes could be enough and it would
# enable (?) parallel runs
src_gisrc = os.environ['GISRC']
tgt_gisrc = gsetup.write_gisrc(tgt_gisdbase,
tgt_location, tgt_mapset_name)
os.environ['GISRC'] = tgt_gisrc
if os.environ.get('WIND_OVERRIDE'):
old_temp_region = os.environ['WIND_OVERRIDE']
del os.environ['WIND_OVERRIDE']
else:
old_temp_region = None
# these lines looks good but anyway when developing the module
# switching location seemed fragile and on some errors (while running
# unfinished module) location was switched in the command line
try:
# the function itself is not safe for other (backgroud) processes
# (e.g. GUI), however we already switched GISRC for us
# and child processes, so we don't influece others
gcore.create_location(dbase=tgt_gisdbase,
location=tgt_location,
epsg=epsg_code,
datum=None,
datum_trans=None)
# Mapset object cannot be created if the real mapset does not exists
tgt_mapset = Mapset(gisdbase=tgt_gisdbase, location=tgt_location,
mapset=tgt_mapset_name)
# set the current mapset in the library
# we actually don't need to switch when only calling modules
# (right GISRC is enough for them)
tgt_mapset.current()
# setting region
if use_region:
# respecting computation region of the src location
# by previous use g.region in src location
# and m.proj and g.region now
# respecting MASK of the src location would be hard
# null values in map are usually enough
tgt_proj_string = get_location_proj_string()
tgt_region = reproject_region(src_region,
from_proj=src_proj_string,
to_proj=tgt_proj_string)
# uses g.region thus and sets region only for child processes
# which is enough now
set_region(tgt_region)
else:
# find out map extent to import everything
# using only classic API because of some problems with pygrass
# on ms windows
rproj_out = gcore.read_command('r.proj', input=map_name,
dbase=src_mapset.gisdbase,
location=src_mapset.location,
mapset=src_mapset.name,
output=map_name, flags='g')
a = gcore.parse_key_val(rproj_out, sep='=', vsep=' ')
gcore.run_command('g.region', **a)
# map import
gcore.run_command('r.proj', input=map_name, dbase=src_mapset.gisdbase,
location=src_mapset.location, mapset=src_mapset.name,
output=map_name)
# actual export
gcore.run_command('r.out.png', input=map_name, output=output_file,
compression=compression, flags=routpng_flags)
# outputting file with WGS84 coordinates
if wgs84_file:
gcore.message("Projecting coordinates to LL WGS 84...")
with open(wgs84_file, 'w') as data_file:
if use_region:
# map which is smaller than region is imported in its own
# small extent, but we export image in region, so we need
# bounds to be for region, not map
# hopefully this is consistent with r.out.png behavior
data_file.write(
map_extent_to_file_content(
proj_to_wgs84(get_region())) + '\n')
else:
# use map to get extent
# the result is actually the same as using map
# if region is the same as map (use_region == False)
data_file.write(
map_extent_to_file_content(
get_map_extent_for_location(map_name))
+ '\n')
finally:
# juts in case we need to do something in the old location
# our callers probably do
os.environ['GISRC'] = src_gisrc
if old_temp_region:
os.environ['WIND_OVERRIDE'] = old_temp_region
# set current in library
src_mapset.current()
# delete the whole gisdbase
# delete file by file to ensure that we are deleting only our things
# exception will be raised when removing non-empty directory
tgt_location_path = Location(gisdbase=tgt_gisdbase,
location=tgt_location).path()
tgt_mapset.delete()
os.rmdir(tgt_location_path)
# dir created by tempfile.mkdtemp() needs to be romved manually
os.rmdir(tgt_gisdbase)
# we have to remove file created by tempfile.mkstemp function
# in write_gisrc function
os.remove(tgt_gisrc)
