"""
Raster related functions to be used in Python scripts.
Usage:
::
from grass.script import raster as grass
grass.raster_history(map)
(C) 2008-2011 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.
.. sectionauthor:: Glynn Clements
.. sectionauthor:: Martin Landa <landa.martin gmail.com>
"""
import os
import string
import time
from .core import (
gisenv,
find_file,
tempfile,
run_command,
read_command,
write_command,
feed_command,
warning,
fatal,
)
from grass.exceptions import CalledModuleError
from .utils import encode, float_or_dms, parse_key_val, try_remove
[docs]def raster_history(map, overwrite=False, env=None):
"""Set the command history for a raster map to the command used to
invoke the script (interface to `r.support`).
:param str map: map name
:param env: environment
:return: True on success
:return: False on failure
"""
current_mapset = gisenv(env)["MAPSET"]
if find_file(name=map, env=env)["mapset"] == current_mapset:
if overwrite is True:
historyfile = tempfile(env=env)
f = open(historyfile, "w")
f.write(os.environ["CMDLINE"])
f.close()
run_command("r.support", map=map, loadhistory=historyfile, env=env)
try_remove(historyfile)
else:
run_command("r.support", map=map, history=os.environ["CMDLINE"], env=env)
return True
warning(
_(
"Unable to write history for <%(map)s>. "
"Raster map <%(map)s> not found in current mapset."
)
% {"map": map},
env=env,
)
return False
[docs]def raster_info(map, env=None):
"""Return information about a raster map (interface to
`r.info -gre`). Example:
>>> raster_info('elevation') # doctest: +ELLIPSIS
{'creator': '"helena"', 'cols': '1500' ... 'south': 215000.0}
:param str map: map name
:param env: environment
:return: parsed raster info
"""
def float_or_null(s):
if s == "NULL":
return None
return float(s)
s = read_command("r.info", flags="gre", map=map, env=env)
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
[docs]def mapcalc(
exp,
quiet=False,
superquiet=False,
verbose=False,
overwrite=False,
seed=None,
env=None,
**kwargs,
):
"""Interface to r.mapcalc.
:param str exp: expression
:param bool quiet: True to run quietly (<tt>--q</tt>)
:param bool superquiet: True to run extra quietly (<tt>--qq</tt>)
:param bool verbose: True to run verbosely (<tt>--v</tt>)
:param bool overwrite: True to enable overwriting the output (<tt>--o</tt>)
:param seed: an integer used to seed the random-number generator for the
rand() function, or 'auto' to generate a random seed
:param dict env: dictionary of environment variables for child process
:param kwargs:
"""
if seed == "auto":
seed = hash((os.getpid(), time.time())) % (2**32)
t = string.Template(exp)
e = t.substitute(**kwargs)
try:
write_command(
"r.mapcalc",
file="-",
stdin=e,
env=env,
seed=seed,
quiet=quiet,
superquiet=superquiet,
verbose=verbose,
overwrite=overwrite,
)
except CalledModuleError:
fatal(
_("An error occurred while running r.mapcalc with expression: %s") % e,
env=env,
)
[docs]def mapcalc_start(
exp,
quiet=False,
superquiet=False,
verbose=False,
overwrite=False,
seed=None,
env=None,
**kwargs,
):
"""Interface to r.mapcalc, doesn't wait for it to finish, returns Popen object.
>>> output = 'newele'
>>> input = 'elevation'
>>> expr1 = '"%s" = "%s" * 10' % (output, input)
>>> expr2 = '...' # etc.
>>> # launch the jobs:
>>> p1 = mapcalc_start(expr1)
>>> p2 = mapcalc_start(expr2)
...
>>> # wait for them to finish:
>>> p1.wait()
0
>>> p2.wait()
1
>>> run_command('g.remove', flags='f', type='raster', name=output)
:param str exp: expression
:param bool quiet: True to run quietly (<tt>--q</tt>)
:param bool superquiet: True to run extra quietly (<tt>--qq</tt>)
:param bool verbose: True to run verbosely (<tt>--v</tt>)
:param bool overwrite: True to enable overwriting the output (<tt>--o</tt>)
:param seed: an integer used to seed the random-number generator for the
rand() function, or 'auto' to generate a random seed
:param dict env: dictionary of environment variables for child process
:param kwargs:
:return: Popen object
"""
if seed == "auto":
seed = hash((os.getpid(), time.time())) % (2**32)
t = string.Template(exp)
e = t.substitute(**kwargs)
p = feed_command(
"r.mapcalc",
file="-",
env=env,
seed=seed,
quiet=quiet,
superquiet=superquiet,
verbose=verbose,
overwrite=overwrite,
)
p.stdin.write(encode(e))
p.stdin.close()
return p
[docs]def raster_what(map, coord, env=None, localized=False):
"""Interface to r.what
>>> raster_what('elevation', [[640000, 228000]])
[{'elevation': {'color': '255:214:000', 'label': '', 'value': '102.479'}}]
:param str map: the map name
:param list coord: a list of list containing all the point that you want
query
:param env:
"""
map_list = [map] if isinstance(map, (bytes, str)) else map
coord_list = []
if isinstance(coord, tuple):
coord_list.append("%f,%f" % (coord[0], coord[1]))
else:
for e, n in coord:
coord_list.append("%f,%f" % (e, n))
sep = "|"
# separator '|' not included in command
# because | is causing problems on Windows
# change separator?
ret = read_command(
"r.what",
flags="rf",
map=",".join(map_list),
coordinates=",".join(coord_list),
null=_("No data"),
quiet=True,
env=env,
)
data = []
if not ret:
return data
if localized:
labels = (_("value"), _("label"), _("color"))
else:
labels = ("value", "label", "color")
for item in ret.splitlines():
line = item.split(sep)[3:]
for i, map_name in enumerate(map_list):
tmp_dict = {}
tmp_dict[map_name] = {}
for j in range(len(labels)):
tmp_dict[map_name][labels[j]] = line[i * len(labels) + j]
data.append(tmp_dict)
return data
