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"""!@package grass.script.raster
@brief GRASS Python scripting module (raster functions)
Raster related functions to be used in Python scripts.
Usage:
@code
from grass.script import raster as grass
grass.raster_history(map)
...
@endcode
(C) 2008-2009 by the GRASS Development Team
This program is free software under the GNU General Public
License (>=v2). Read the file COPYING that comes with GRASS
for details.
@author Glynn Clements
@author Martin Landa <landa.martin gmail.com>
"""
import os
import string
from core import *
# i18N
import gettext
gettext.install('grasslibs', os.path.join(os.getenv("GISBASE"), 'locale'), unicode=True)
# add raster history
def raster_history(map):
"""!Set the command history for a raster map to the command used to
invoke the script (interface to `r.support').
@param map map name
@return True on success
@return False on failure
"""
current_mapset = gisenv()['MAPSET']
if find_file(name = map)['mapset'] == current_mapset:
run_command('r.support', map = map, history = os.environ['CMDLINE'])
return True
warning(_("Unable to write history for <%(map)s>. "
"Raster map <%(map)s> not found in current mapset." % { 'map' : map, 'map' : map}))
return False
# run "r.info -rgstmpud ..." and parse output
def raster_info(map):
"""!Return information about a raster map (interface to
`r.info'). Example:
\code
>>> grass.raster_info('elevation')
{'north': 228500.0, 'timestamp': '"none"', 'min': 55.578792572021499,
'datatype': 'FCELL', 'max': 156.32986450195301, 'ewres': 10.0,
'vertical_datum': '', 'west': 630000.0, 'units': '',
'title': 'South-West Wake county: Elevation NED 10m (elev_ned10m)',
'east': 645000.0, 'nsres': 10.0, 'south': 215000.0}
\endcode
@param map map name
@return parsed raster info
"""
def float_or_null(s):
if s == 'NULL':
return None
else:
return float(s)
s = read_command('r.info', flags = 'rgstmpud', map = map)
kv = parse_key_val(s)
for k in ['min', 'max']:
kv[k] = float_or_null(kv[k])
for k in ['north', 'south', 'east', 'west']:
kv[k] = float(kv[k])
for k in ['nsres', 'ewres']:
kv[k] = float_or_dms(kv[k])
return kv
# interface to r.mapcalc
def mapcalc(exp, quiet = False, verbose = False, overwrite = False, **kwargs):
"""!Interface to r.mapcalc.
@param exp expression
@param kwargs
"""
t = string.Template(exp)
e = t.substitute(**kwargs)
env = os.environ.copy()
if quiet:
env['GRASS_VERBOSE'] = '0'
if verbose:
env['GRASS_VERBOSE'] = '3'
if overwrite:
env['GRASS_OVERWRITE'] = '1'
if write_command('r.mapcalc', stdin = e, env = env) != 0:
fatal(_("An error occurred while running r.mapcalc"))
def mapcalc_start(exp, quiet = False, verbose = False, overwrite = False, **kwargs):
"""!Interface to r.mapcalc, doesn't wait for it to finish, returns Popen object.
\code
>>> expr1 = '"%s" = "%s" * 10' % (output, input)
>>> expr2 = '...' # etc.
>>> # launch the jobs:
>>> p1 = grass.mapcalc_start(expr1)
>>> p2 = grass.mapcalc_start(expr2) # etc.
...
>>> # wait for them to finish:
>>> p1.wait()
>>> p2.wait() # etc.
\endcode
@param exp expression
@param kwargs
@return Popen object
"""
t = string.Template(exp)
e = t.substitute(**kwargs)
env = os.environ.copy()
if quiet:
env['GRASS_VERBOSE'] = '0'
if verbose:
env['GRASS_VERBOSE'] = '3'
if overwrite:
env['GRASS_OVERWRITE'] = '1'
stdin = e
p = feed_command('r.mapcalc', env = env, **kwargs)
p.stdin.write(stdin)
p.stdin.close()
return p
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