def num_primitive_of(self, primitive):
"""Return the number of primitive
:param primitive: the name of primitive to query; the supported values are:
* *boundary*,
* *centroid*,
* *face*,
* *kernel*,
* *line*,
* *point*
* *area*
* *volume*
:type primitive: str
::
>>> test_vect = VectorTopo(test_vector_name)
>>> test_vect.open(mode='r')
>>> test_vect.num_primitive_of('point')
3
>>> test_vect.num_primitive_of('line')
3
>>> test_vect.num_primitive_of('centroid')
4
>>> test_vect.num_primitive_of('boundary')
11
>>> test_vect.close()
..
"""
return libvect.Vect_get_num_primitives(self.c_mapinfo,
VTYPE[primitive])
def num_primitive_of(self, primitive):
"""Primitive are:
* "boundary",
* "centroid",
* "face",
* "kernel",
* "line",
* "point"
::
>>> rail = VectTopo('rail')
>>> rail.open()
>>> rail.num_primitive_of('line')
10837
>>> municip = VectTopo('boundary_municp_sqlite')
>>> municip.open()
>>> municip.num_primitive_of('line')
0
>>> municip.num_primitive_of('centroid')
3579
>>> municip.num_primitive_of('boundary')
5128
>>> rail.close()
>>> municip.close()
..
"""
return libvect.Vect_get_num_primitives(self.c_mapinfo,
VTYPE[primitive])
def getcoords(self):
""" Method creating a dict() of point coordinates: {a:(xa,ya), b:(xb,yb)...} """
# Create a new Map_info() object
map = vect.pointer(vect.Map_info())
# Load the vector map to Map_info() object. Level should be 2 (with topology)
vect.Vect_open_old2(map, self.layer, "", "-1")
# Get number of point features (1) in the layer
n_lines = vect.Vect_get_num_primitives(map, 1)
# Create new line and categories structures
line = vect.Vect_new_line_struct()
cats = vect.Vect_new_cats_struct()
# Make an empty list to store all feature cats and their coordinates in
coordsdict = {}
# Iterate through all features and write their coordinates to the list
for i in xrange(0, n_lines):
# Read next line from Map_info()
vect.Vect_read_next_line(map, line, cats, 1)
# Get line structure values, i.e. coordinates
x = line.contents.x[0]
y = line.contents.y[0]
# Get the point category number
cat = cats.contents.cat[0]
coordsdict[cat] = (x, y)
# Do some cleanup
vect.Vect_destroy_line_struct(line)
vect.Vect_destroy_cats_struct(cats)
vect.Vect_close(map)
# Return coordinate dictionary. Example: {1: (635185.6745587245, 6434401.869609355), 3: (634763.0860512792, 6437526.1793751), 4: (636855.7953351085, 6435785.045250954), 5: (636705.1202666728, 6432286.035328391), 6: (633607.9105266054, 6432286.035328391), 7: (632762.4559759387, 6435655.297275356)}
return coordsdict
def featcount(self):
""" Method returning the number of features in the layer """
# Create a new Map_info() object
map = vect.pointer(vect.Map_info())
# Load the vector map to Map_info() object. Level should be 2 (with topology)
vect.Vect_open_old2(map, self.layer, "", "-1")
# Get number of point features (1) in the layer
n_feats = vect.Vect_get_num_primitives(map, 1)
# Close the Map_info() object
vect.Vect_close(map)
# Return number of features in the layer (integer)
return n_feats
def _read_vector_info(name, mapset):
"""Read the vector map info from the file system and store the content
into a dictionary
This method uses the ctypes interface to the vector libraries
to read the map metadata information
:param name: The name of the map
:param mapset: The mapset of the map
:returns: The key value pairs of the map specific metadata, or None in
case of an error
"""
kvp = {}
if not libgis.G_find_vector(name, mapset):
return None
# The vector map structure
Map = libvector.Map_info()
# We open the maps always in topology mode first
libvector.Vect_set_open_level(2)
with_topo = True
# Code lend from v.info main.c
if libvector.Vect_open_old_head2(byref(Map), name, mapset, "1") < 2:
# force level 1, open fully
# NOTE: number of points, lines, boundaries, centroids,
# faces, kernels is still available
libvector.Vect_set_open_level(1) # no topology
with_topo = False
if libvector.Vect_open_old2(byref(Map), name, mapset, "1") < 1:
logging.error(
_("Unable to open vector map <%s>" %
(libvector.Vect_get_full_name(byref(Map)))))
return None
# Release the vector spatial index memory when closed
libvector.Vect_set_release_support(byref(Map))
# Read the extent information
bbox = libvector.bound_box()
libvector.Vect_get_map_box(byref(Map), byref(bbox))
kvp["north"] = bbox.N
kvp["south"] = bbox.S
kvp["east"] = bbox.E
kvp["west"] = bbox.W
kvp["top"] = bbox.T
kvp["bottom"] = bbox.B
kvp["map3d"] = bool(libvector.Vect_is_3d(byref(Map)))
# Read number of features
if with_topo:
kvp["points"] = libvector.Vect_get_num_primitives(
byref(Map), libvector.GV_POINT)
kvp["lines"] = libvector.Vect_get_num_primitives(
byref(Map), libvector.GV_LINE)
kvp["boundaries"] = libvector.Vect_get_num_primitives(
byref(Map), libvector.GV_BOUNDARY)
kvp["centroids"] = libvector.Vect_get_num_primitives(
byref(Map), libvector.GV_CENTROID)
kvp["faces"] = libvector.Vect_get_num_primitives(
byref(Map), libvector.GV_FACE)
kvp["kernels"] = libvector.Vect_get_num_primitives(
byref(Map), libvector.GV_KERNEL)
# Summarize the primitives
kvp["primitives"] = kvp["points"] + kvp["lines"] + \
kvp["boundaries"] + kvp["centroids"]
if kvp["map3d"]:
kvp["primitives"] += kvp["faces"] + kvp["kernels"]
# Read topology information
kvp["nodes"] = libvector.Vect_get_num_nodes(byref(Map))
kvp["areas"] = libvector.Vect_get_num_areas(byref(Map))
kvp["islands"] = libvector.Vect_get_num_islands(byref(Map))
kvp["holes"] = libvector.Vect_get_num_holes(byref(Map))
kvp["volumes"] = libvector.Vect_get_num_primitives(
byref(Map), libvector.GV_VOLUME)
else:
kvp["points"] = None
kvp["lines"] = None
kvp["boundaries"] = None
kvp["centroids"] = None
kvp["faces"] = None
kvp["kernels"] = None
kvp["primitives"] = None
kvp["nodes"] = None
kvp["areas"] = None
kvp["islands"] = None
kvp["holes"] = None
kvp["volumes"] = None
libvector.Vect_close(byref(Map))
return kvp