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Source code for temporal.extract

"""
Extract functions for space time raster, 3d raster and vector datasets

(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
"""
# i18N
import gettext
from .core import get_tgis_message_interface, get_current_mapset, SQLDatabaseInterfaceConnection
from .abstract_map_dataset import AbstractMapDataset
from .open_stds import open_old_stds, check_new_stds, open_new_stds
from .datetime_math import create_suffix_from_datetime
from .datetime_math import create_time_suffix
from .datetime_math import create_numeric_suffic
from multiprocessing import Process
import grass.script as gscript
from grass.exceptions import CalledModuleError

############################################################################


[docs]def extract_dataset(input, output, type, where, expression, base, time_suffix, nprocs=1, register_null=False, layer=1, vtype="point,line,boundary,centroid,area,face", ): """Extract a subset of a space time raster, raster3d or vector dataset A mapcalc expression can be provided to process the temporal extracted maps. Mapcalc expressions are supported for raster and raster3d maps. :param input: The name of the input space time raster/raster3d dataset :param output: The name of the extracted new space time raster/raster3d dataset :param type: The type of the dataset: "raster", "raster3d" or vector :param where: The temporal SQL WHERE statement for subset extraction :param expression: The r(3).mapcalc expression or the v.extract where statement :param base: The base name of the new created maps in case a mapclac expression is provided :param time_suffix: string to choose which suffix to use: gran, time, num%* (where * are digits) :param nprocs: The number of parallel processes to be used for mapcalc processing :param register_null: Set this number True to register empty maps (only raster and raster3d maps) :param layer: The vector layer number to be used when no timestamped layer is present, default is 1 :param vtype: The feature type to be extracted for vector maps, default is point,line,boundary,centroid,area and face """ # Check the parameters msgr = get_tgis_message_interface() if expression and not base: msgr.fatal(_("You need to specify the base name of new created maps")) mapset = get_current_mapset() dbif = SQLDatabaseInterfaceConnection() dbif.connect() sp = open_old_stds(input, type, dbif) # Check the new stds new_sp = check_new_stds(output, type, dbif, gscript.overwrite()) if type == "vector": rows = sp.get_registered_maps( "id,name,mapset,layer", where, "start_time", dbif) else: rows = sp.get_registered_maps("id", where, "start_time", dbif) new_maps = {} if rows: num_rows = len(rows) msgr.percent(0, num_rows, 1) # Run the mapcalc expression if expression: count = 0 proc_count = 0 proc_list = [] for row in rows: count += 1 if count % 10 == 0: msgr.percent(count, num_rows, 1) if sp.get_temporal_type() == 'absolute' and time_suffix == 'gran': old_map = sp.get_new_map_instance(row["id"]) old_map.select(dbif) suffix = create_suffix_from_datetime(old_map.temporal_extent.get_start_time(), sp.get_granularity()) map_name = "{ba}_{su}".format(ba=base, su=suffix) elif sp.get_temporal_type() == 'absolute' and time_suffix == 'time': old_map = sp.get_new_map_instance(row["id"]) old_map.select(dbif) suffix = create_time_suffix(old_map) map_name = "{ba}_{su}".format(ba=base, su=suffix) else: map_name = create_numeric_suffic(base, count, time_suffix) # We need to modify the r(3).mapcalc expression if type != "vector": expr = expression expr = expr.replace(sp.base.get_map_id(), row["id"]) expr = expr.replace(sp.base.get_name(), row["id"]) expr = "%s = %s" % (map_name, expr) # We need to build the id map_id = AbstractMapDataset.build_id(map_name, mapset) else: map_id = AbstractMapDataset.build_id(map_name, mapset, row["layer"]) new_map = sp.get_new_map_instance(map_id) # Check if new map is in the temporal database if new_map.is_in_db(dbif): if gscript.overwrite(): # Remove the existing temporal database entry new_map.delete(dbif) new_map = sp.get_new_map_instance(map_id) else: msgr.error(_("Map <%s> is already in temporal database" ", use overwrite flag to overwrite") % (new_map.get_map_id())) continue # Add process to the process list if type == "raster": msgr.verbose(_("Applying r.mapcalc expression: \"%s\"") % expr) proc_list.append(Process(target=run_mapcalc2d, args=(expr,))) elif type == "raster3d": msgr.verbose(_("Applying r3.mapcalc expression: \"%s\"") % expr) proc_list.append(Process(target=run_mapcalc3d, args=(expr,))) elif type == "vector": msgr.verbose(_("Applying v.extract where statement: \"%s\"") % expression) if row["layer"]: proc_list.append(Process(target=run_vector_extraction, args=(row["name"] + "@" + row["mapset"], map_name, row["layer"], vtype, expression))) else: proc_list.append(Process(target=run_vector_extraction, args=(row["name"] + "@" + row["mapset"], map_name, layer, vtype, expression))) proc_list[proc_count].start() proc_count += 1 # Join processes if the maximum number of processes are # reached or the end of the loop is reached if proc_count == nprocs or count == num_rows: proc_count = 0 exitcodes = 0 for proc in proc_list: proc.join() exitcodes += proc.exitcode if exitcodes != 0: dbif.close() msgr.fatal(_("Error in computation process")) # Empty process list proc_list = [] # Store the new maps new_maps[row["id"]] = new_map msgr.percent(0, num_rows, 1) temporal_type, semantic_type, title, description = sp.get_initial_values() new_sp = open_new_stds(output, type, sp.get_temporal_type(), title, description, semantic_type, dbif, gscript.overwrite()) # collect empty maps to remove them empty_maps = [] # Register the maps in the database count = 0 for row in rows: count += 1 if count % 10 == 0: msgr.percent(count, num_rows, 1) old_map = sp.get_new_map_instance(row["id"]) old_map.select(dbif) if expression: # Register the new maps if row["id"] in new_maps: new_map = new_maps[row["id"]] # Read the raster map data new_map.load() # In case of a empty map continue, do not register empty # maps if type == "raster" or type == "raster3d": if new_map.metadata.get_min() is None and \ new_map.metadata.get_max() is None: if not register_null: empty_maps.append(new_map) continue elif type == "vector": if new_map.metadata.get_number_of_primitives() == 0 or \ new_map.metadata.get_number_of_primitives() is None: if not register_null: empty_maps.append(new_map) continue # Set the time stamp new_map.set_temporal_extent(old_map.get_temporal_extent()) # Insert map in temporal database new_map.insert(dbif) new_sp.register_map(new_map, dbif) else: new_sp.register_map(old_map, dbif) # Update the spatio-temporal extent and the metadata table entries new_sp.update_from_registered_maps(dbif) msgr.percent(num_rows, num_rows, 1) # Remove empty maps if len(empty_maps) > 0: names = "" count = 0 for map in empty_maps: if count == 0: names += "%s" % (map.get_name()) else: names += ",%s" % (map.get_name()) count += 1 if type == "raster": gscript.run_command("g.remove", flags='f', type='raster', name=names, quiet=True) elif type == "raster3d": gscript.run_command("g.remove", flags='f', type='raster_3d', name=names, quiet=True) elif type == "vector": gscript.run_command("g.remove", flags='f', type='vector', name=names, quiet=True) dbif.close() ###############################################################################
[docs]def run_mapcalc2d(expr): """Helper function to run r.mapcalc in parallel""" try: gscript.run_command("r.mapcalc", expression=expr, overwrite=gscript.overwrite(), quiet=True) except CalledModuleError: exit(1)
[docs]def run_mapcalc3d(expr): """Helper function to run r3.mapcalc in parallel""" try: gscript.run_command("r3.mapcalc", expression=expr, overwrite=gscript.overwrite(), quiet=True) except CalledModuleError: exit(1)
[docs]def run_vector_extraction(input, output, layer, type, where): """Helper function to run r.mapcalc in parallel""" try: gscript.run_command("v.extract", input=input, output=output, layer=layer, type=type, where=where, overwrite=gscript.overwrite(), quiet=True) except CalledModuleError: exit(1)

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