script.raster — GRASS Python Library documentation

# Source code for script.raster

    """
    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

    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, "map": map}
            )
        )
        return False

    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
            else:
                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

    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)

    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

    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:
        """
        if isinstance(map, (bytes, str)):
            map_list = [map]
        else:
            map_list = map

        coord_list = 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 = list()
        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

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