grass.temporal.sampling — GRASS Python Library documentation

# Source code for grass.temporal.sampling

    """
    Sampling functions for space time datasets

    Usage:

    .. code-block:: python

        import grass.temporal as tgis

        tgis.register_maps_in_space_time_dataset(type, name, maps)

    (C) 2012-2013 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.

    :authors: Soeren Gebbert
    """

    from .core import (
        get_current_mapset,
        get_tgis_message_interface,
        SQLDatabaseInterfaceConnection,
    )
    from .datetime_math import time_delta_to_relative_time
    from .factory import dataset_factory

    def sample_stds_by_stds_topology(
        intype,
        sampletype,
        inputs,
        sampler,
        header,
        separator,
        method,
        spatial=False,
        print_only=True,
    ):
        """Sample the input space time datasets with a sample
        space time dataset, return the created map matrix and optionally
        print the result to stdout

         In case multiple maps are located in the current granule,
         the map names are separated by comma.

         In case a layer is present, the names map ids are extended
         in this form: "name:layer@mapset"

         Attention: Do not use the comma as separator for printing

         :param intype: Type of the input space time dataset (strds, stvds or
                        str3ds)
         :param sampletype: Type of the sample space time datasets (strds,
                            stvds or str3ds)
         :param inputs: Name or comma separated names of space time datasets or
                        a list of map names
         :param sampler: Name of a space time dataset used for temporal sampling
         :param header: Set True to print column names
         :param separator: The field separator character between the columns
         :param method: The method to be used for temporal sampling
                        (start,during,contain,overlap,equal) as comma separated
                        string or as a list of methods
         :param spatial: Perform spatial overlapping check
         :param print_only: If set True (default) then the result of the
                            sampling will be printed to stdout, if set to False
                            the resulting map matrix will be returned.

         :return: The map matrix or None if nothing found
        """
        mapset = get_current_mapset()
        msgr = get_tgis_message_interface()

        # Make a method list
        if not issubclass(type(method), type([])):
            method = method.split(",")

        # Split the inputs
        if not issubclass(type(inputs), type([])):
            inputs = inputs.split(",")

        sts = []

        for input in inputs:
            if input.find("@") >= 0:
                id = input
            else:
                id = input + "@" + mapset

            st = dataset_factory(intype, id)
            sts.append(st)

        if sampler.find("@") >= 0:
            sid = sampler
        else:
            sid = sampler + "@" + mapset

        sst = dataset_factory(sampletype, sid)

        dbif = SQLDatabaseInterfaceConnection()
        dbif.connect()

        for st in sts:
            if st.is_in_db(dbif) is False:
                msgr.fatal(_("Dataset <%s> not found in temporal database") % (st.get_id()))
            st.select(dbif)

        if sst.is_in_db(dbif) is False:
            msgr.fatal(_("Dataset <%s> not found in temporal database") % (sid))

        sst.select(dbif)

        if separator is None or separator == "" or separator.find(",") >= 0:
            separator = " | "

        mapmatrizes = []
        for st in sts:
            mapmatrix = st.sample_by_dataset(sst, method, spatial, dbif)
            if mapmatrix and len(mapmatrix) > 0:
                mapmatrizes.append(mapmatrix)

        if len(mapmatrizes) > 0:
            # Simply return the map matrix
            if not print_only:
                dbif.close()
                return mapmatrizes

            if header:
                string = ""
                string += "%s%s" % (sst.get_id(), separator)
                for st in sts:
                    string += "%s%s" % (st.get_id(), separator)
                string += "%s%s" % ("start_time", separator)
                string += "%s%s" % ("end_time", separator)
                string += "%s%s" % ("interval_length", separator)
                string += "%s" % ("distance_from_begin")
                print(string)

            first_time, dummy = mapmatrizes[0][0]["granule"].get_temporal_extent_as_tuple()

            for i in range(len(mapmatrizes[0])):
                mapname_list = []
                for mapmatrix in mapmatrizes:
                    mapnames = ""
                    count = 0
                    entry = mapmatrix[i]
                    for sample in entry["samples"]:
                        if count == 0:
                            mapnames += str(sample.get_id())
                        else:
                            mapnames += ",%s" % str(sample.get_id())
                        count += 1
                    mapname_list.append(mapnames)

                entry = mapmatrizes[0][i]
                map = entry["granule"]

                start, end = map.get_temporal_extent_as_tuple()
                if end:
                    delta = end - start
                else:
                    delta = None
                delta_first = start - first_time

                if map.is_time_absolute():
                    if end:
                        delta = time_delta_to_relative_time(delta)
                    delta_first = time_delta_to_relative_time(delta_first)

                string = ""
                string += "%s%s" % (map.get_id(), separator)
                for mapnames in mapname_list:
                    string += "%s%s" % (mapnames, separator)
                string += "%s%s" % (start, separator)
                string += "%s%s" % (end, separator)
                string += "%s%s" % (delta, separator)
                string += "%s" % (delta_first)
                print(string)

        dbif.close()
        if len(mapmatrizes) > 0:
            return mapmatrizes

        return None

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