"""
Vector related functions to be used in Python scripts.
Usage:
::
from grass.script import vector as grass
grass.vector_db(map)
(C) 2008-2010 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>
"""
from __future__ import absolute_import
import os
import sys
from .utils import parse_key_val
from .core import (
run_command,
read_command,
error,
fatal,
debug,
)
from grass.exceptions import CalledModuleError, ScriptError
unicode = str
[docs]def vector_db(map, env=None, **kwargs):
"""Return the database connection details for a vector map
(interface to `v.db.connect -g`). Example:
>>> vector_db('geology') # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
{1: {'layer': 1, ... 'table': 'geology'}}
:param str map: vector map
:param kwargs: other v.db.connect's arguments
:param env: environment
:return: dictionary
"""
s = read_command(
"v.db.connect", quiet=True, flags="g", map=map, sep=";", env=env, **kwargs
)
result = {}
for line in s.splitlines():
f = line.split(";")
if len(f) != 5:
continue
if "/" in f[0]:
f1 = f[0].split("/")
layer = f1[0]
name = f1[1]
else:
layer = f[0]
name = ""
result[int(layer)] = {
"layer": int(layer),
"name": name,
"table": f[1],
"key": f[2],
"database": f[3],
"driver": f[4],
}
return result
[docs]def vector_layer_db(map, layer, env=None):
"""Return the database connection details for a vector map layer.
If db connection for given layer is not defined, fatal() is called.
:param str map: map name
:param layer: layer number
:param env: environment
:return: parsed output
"""
try:
f = vector_db(map, env=env)[int(layer)]
except KeyError:
fatal(_("Database connection not defined for layer %s") % layer)
return f
# run "v.info -c ..." and parse output
[docs]def vector_columns(map, layer=None, getDict=True, env=None, **kwargs):
"""Return a dictionary (or a list) of the columns for the
database table connected to a vector map (interface to `v.info -c`).
>>> vector_columns('geology', getDict=True) # doctest: +NORMALIZE_WHITESPACE
{'PERIMETER': {'index': 2, 'type': 'DOUBLE PRECISION'}, 'GEOL250_':
{'index': 3, 'type': 'INTEGER'}, 'SHAPE_area': {'index': 6, 'type':
'DOUBLE PRECISION'}, 'onemap_pro': {'index': 1, 'type': 'DOUBLE
PRECISION'}, 'SHAPE_len': {'index': 7, 'type': 'DOUBLE PRECISION'},
'cat': {'index': 0, 'type': 'INTEGER'}, 'GEOL250_ID': {'index': 4, 'type':
'INTEGER'}, 'GEO_NAME': {'index': 5, 'type': 'CHARACTER'}}
>>> vector_columns('geology', getDict=False) # doctest: +NORMALIZE_WHITESPACE
['cat',
'onemap_pro',
'PERIMETER',
'GEOL250_',
'GEOL250_ID',
'GEO_NAME',
'SHAPE_area',
'SHAPE_len']
:param str map: map name
:param layer: layer number or name (None for all layers)
:param bool getDict: True to return dictionary of columns otherwise list
of column names is returned
:param kwargs: (v.info's arguments)
:param env: environment
:return: dictionary/list of columns
"""
s = read_command(
"v.info", flags="c", map=map, layer=layer, quiet=True, env=env, **kwargs
)
if getDict:
result = dict()
else:
result = list()
i = 0
for line in s.splitlines():
ctype, cname = line.split("|")
if getDict:
result[cname] = {"type": ctype, "index": i}
else:
result.append(cname)
i += 1
return result
[docs]def vector_history(map, replace=False, env=None):
"""Set the command history for a vector map to the command used to
invoke the script (interface to `v.support`).
:param str map: mapname
:param bool replace: Replace command line instead of appending it
:param env: environment
:return: v.support output
"""
run_command(
"v.support",
map=map,
cmdhist=os.environ["CMDLINE"],
flags="h" if replace else None,
env=env,
)
[docs]def vector_info_topo(map, layer=1, env=None):
"""Return information about a vector map (interface to `v.info -t`).
Example:
>>> vector_info_topo('geology') # doctest: +NORMALIZE_WHITESPACE
{'lines': 0, 'centroids': 1832, 'boundaries': 3649, 'points': 0,
'primitives': 5481, 'islands': 907, 'nodes': 2724, 'map3d': False,
'areas': 1832}
:param str map: map name
:param int layer: layer number
:param env: environment
:return: parsed output
"""
s = read_command("v.info", flags="t", layer=layer, map=map, env=env)
ret = parse_key_val(s, val_type=int)
if "map3d" in ret:
ret["map3d"] = bool(ret["map3d"])
return ret
[docs]def vector_info(map, layer=1, env=None):
"""Return information about a vector map (interface to
`v.info`). Example:
>>> vector_info('geology') # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE
{'comment': '', 'projection': 'Lambert Conformal Conic' ... 'south': 10875.8272320917}
:param str map: map name
:param int layer: layer number
:param env: environment
:return: parsed vector info
"""
s = read_command("v.info", flags="get", layer=layer, map=map, env=env)
kv = parse_key_val(s)
for k in ["north", "south", "east", "west", "top", "bottom"]:
kv[k] = float(kv[k])
for k in ["level", "num_dblinks"]:
kv[k] = int(kv[k])
for k in [
"nodes",
"points",
"lines",
"boundaries",
"centroids",
"areas",
"islands",
"primitives",
]:
kv[k] = int(kv[k])
if "map3d" in kv:
kv["map3d"] = bool(int(kv["map3d"]))
if kv["map3d"]:
for k in ["faces", "kernels", "volumes", "holes"]:
kv[k] = int(kv[k])
return kv
[docs]def vector_db_select(map, layer=1, env=None, **kwargs):
"""Get attribute data of selected vector map layer.
Function returns list of columns and dictionary of values ordered by
key column value. Example:
>>> print vector_db_select('geology')['columns']
['cat', 'onemap_pro', 'PERIMETER', 'GEOL250_', 'GEOL250_ID', 'GEO_NAME', 'SHAPE_area', 'SHAPE_len']
>>> print vector_db_select('geology')['values'][3]
['3', '579286.875', '3335.55835', '4', '3', 'Zml', '579286.829631', '3335.557182']
>>> print vector_db_select('geology', columns = 'GEO_NAME')['values'][3]
['Zml']
:param str map: map name
:param int layer: layer number
:param kwargs: v.db.select options
:param env: environment
:return: dictionary ('columns' and 'values')
"""
try:
key = vector_db(map=map, env=env)[layer]["key"]
except KeyError:
error(
_("Missing layer %(layer)d in vector map <%(map)s>")
% {"layer": layer, "map": map}
)
return {"columns": [], "values": {}}
include_key = True
if "columns" in kwargs:
if key not in kwargs["columns"].split(","):
# add key column if missing
include_key = False
debug("Adding key column to the output")
kwargs["columns"] += "," + key
ret = read_command("v.db.select", map=map, layer=layer, env=env, **kwargs)
if not ret:
error(_("vector_db_select() failed"))
return {"columns": [], "values": {}}
columns = []
values = {}
for line in ret.splitlines():
if not columns:
columns = line.split("|")
key_index = columns.index(key)
# discard key column
if not include_key:
columns = columns[:-1]
continue
value = line.split("|")
key_value = int(value[key_index])
if not include_key:
# discard key column
values[key_value] = value[:-1]
else:
values[key_value] = value
return {"columns": columns, "values": values}
json = None
orderedDict = None
[docs]def vector_what(
map,
coord,
distance=0.0,
ttype=None,
encoding=None,
skip_attributes=False,
layer=None,
multiple=False,
env=None,
):
"""Query vector map at given locations
To query one vector map at one location
::
print grass.vector_what(map='archsites', coord=(595743, 4925281),
distance=250)
[{'Category': 8, 'Map': 'archsites', 'Layer': 1, 'Key_column': 'cat',
'Database': '/home/martin/grassdata/spearfish60/PERMANENT/dbf/',
'Mapset': 'PERMANENT', 'Driver': 'dbf',
'Attributes': {'str1': 'No_Name', 'cat': '8'},
'Table': 'archsites', 'Type': 'Point', 'Id': 8}]
To query one vector map with multiple layers (no additional parameters
required)
::
for q in grass.vector_what(map='some_map', distance=100.0,
coord=(596532.357143,4920486.21429)):
print q['Map'], q['Layer'], q['Attributes']
new_bug_sites 1 {'str1': 'Beetle_site', 'GRASSRGB': '', 'cat': '80'}
new_bug_sites 2 {'cat': '80'}
To query more vector maps at one location
::
for q in grass.vector_what(map=('archsites', 'roads'),
coord=(595743, 4925281), distance=250):
print q['Map'], q['Attributes']
archsites {'str1': 'No_Name', 'cat': '8'}
roads {'label': 'interstate', 'cat': '1'}
To query one vector map at more locations
::
for q in grass.vector_what(map='archsites', distance=250,
coord=[(595743, 4925281), (597950, 4918898)]):
print q['Map'], q['Attributes']
archsites {'str1': 'No_Name', 'cat': '8'}
archsites {'str1': 'Bob_Miller', 'cat': '22'}
:param map: vector map(s) to query given as string or list/tuple
:param coord: coordinates of query given as tuple (easting, northing) or
list of tuples
:param distance: query threshold distance (in map units)
:param ttype: list of topology types (default of v.what are point, line,
area, face)
:param encoding: attributes encoding
:param skip_attributes: True to skip querying attributes
:param layer: layer number or list of layers (one for each vector),
if None, all layers (-1) are used
:param multiple: find multiple features within threshold distance
:param env: environment
:return: parsed list
"""
if not env:
env = os.environ.copy()
if "LC_ALL" in env:
env["LC_ALL"] = "C"
if isinstance(map, (bytes, unicode)):
map_list = [map]
else:
map_list = map
if layer:
if isinstance(layer, (tuple, list)):
layer_list = [str(item) for item in layer]
else:
layer_list = [str(layer)]
if len(layer_list) != len(map_list):
raise ScriptError(
_(
"Number of given vector maps ({m}) "
"differs from number of layers ({l})"
).format(m=len(map_list), l=len(layer_list))
)
else:
layer_list = ["-1"] * len(map_list)
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))
flags = "j"
if not skip_attributes:
flags += "a"
if multiple:
flags += "m"
cmdParams = dict(
quiet=True,
flags=flags,
map=",".join(map_list),
layer=",".join(layer_list),
coordinates=",".join(coord_list),
distance=float(distance),
)
if ttype:
cmdParams["type"] = ",".join(ttype)
try:
ret = read_command("v.what", env=env, **cmdParams).strip()
except CalledModuleError as e:
raise ScriptError(e.msg)
data = list()
if not ret:
return data
# lazy import
global json
global orderedDict
if json is None:
import json
if orderedDict is None:
try:
from collections import OrderedDict
orderedDict = OrderedDict
except ImportError:
orderedDict = dict
kwargs = {}
if encoding:
kwargs["encoding"] = encoding
if sys.version_info[0:2] > (2, 6):
kwargs["object_pairs_hook"] = orderedDict
try:
result = json.loads(ret, **kwargs)
except ValueError:
raise ScriptError(
_("v.what output is not valid JSON format:\n {ret}").format(ret=ret)
)
if multiple:
for vmap in result["Maps"]:
features = vmap.pop("Features", None)
if features:
for feature in features:
cats = feature.pop("Categories", None)
if cats:
for cat in cats:
tmp = feature.copy()
tmp.update(cat)
tmp2 = vmap.copy()
tmp2.update(tmp)
data.append(tmp2)
else:
for vmap in result["Maps"]:
cats = vmap.pop("Categories", None)
if cats:
for cat in cats:
tmp = vmap.copy()
tmp.update(cat)
data.append(tmp)
else:
data.append(vmap)
return data
