def viter(self, vtype, idonly=False):
"""Return an iterator of vector features
:param vtype: the name of type to query; the supported values are:
*areas*, *dblinks*, *faces*, *holes*, *islands*,
*kernels*, *line_points*, *lines*, *nodes*, *points*,
*update_lines*, *update_nodes*, *volumes*
:type vtype: str
:param idonly: variable to return only the id of features instead of
full features
:type idonly: bool
>>> test_vect = VectorTopo(test_vector_name, mode='r')
>>> test_vect.open(mode='r')
>>> areas = [area for area in test_vect.viter('areas')]
>>> areas[:3]
[Area(1), Area(2), Area(3)]
to sort the result in a efficient way, use: ::
>>> from operator import methodcaller as method
>>> areas.sort(key=method('area'), reverse=True) # sort the list
>>> for area in areas[:3]:
... print(area, area.area())
Area(1) 12.0
Area(2) 8.0
Area(4) 8.0
>>> areas = [area for area in test_vect.viter('areas')]
>>> for area in areas:
... print(area.centroid().cat)
3
3
3
3
>>> test_vect.close()
"""
if vtype in _GEOOBJ.keys():
if _GEOOBJ[vtype] is not None:
ids = (indx for indx in range(1, self.number_of(vtype) + 1))
if idonly:
return ids
return (_GEOOBJ[vtype](
v_id=indx,
c_mapinfo=self.c_mapinfo,
table=self.table,
writeable=self.writeable,
) for indx in ids)
else:
keys = "', '".join(sorted(_GEOOBJ.keys()))
raise ValueError("vtype not supported, use one of: '%s'" % keys)
def viter(self, vtype, idonly=False):
"""Return an iterator of vector features
:param vtype: the name of type to query; the supported values are:
*areas*, *dblinks*, *faces*, *holes*, *islands*,
*kernels*, *line_points*, *lines*, *nodes*, *points*,
*update_lines*, *update_nodes*, *volumes*
:type vtype: str
:param idonly: variable to return only the id of features instead of
full features
:type idonly: bool
>>> test_vect = VectorTopo(test_vector_name, mode='r')
>>> test_vect.open(mode='r')
>>> areas = [area for area in test_vect.viter('areas')]
>>> areas[:3]
[Area(1), Area(2), Area(3)]
to sort the result in a efficient way, use: ::
>>> from operator import methodcaller as method
>>> areas.sort(key=method('area'), reverse=True) # sort the list
>>> for area in areas[:3]:
... print(area, area.area())
Area(1) 12.0
Area(2) 8.0
Area(4) 8.0
>>> areas = [area for area in test_vect.viter('areas')]
>>> for area in areas:
... print(area.centroid().cat)
3
3
3
3
>>> test_vect.close()
"""
if vtype in _GEOOBJ.keys():
if _GEOOBJ[vtype] is not None:
ids = (indx for indx in range(1, self.number_of(vtype) + 1))
if idonly:
return ids
return (_GEOOBJ[vtype](v_id=indx, c_mapinfo=self.c_mapinfo,
table=self.table,
writeable=self.writeable)
for indx in ids)
else:
keys = "', '".join(sorted(_GEOOBJ.keys()))
raise ValueError("vtype not supported, use one of: '%s'" % keys)
def cat(self, cat_id, vtype, layer=None, generator=False, geo=None):
"""Return the geometry features with category == cat_id.
:param cat_id: the category number
:type cat_id: int
:param vtype: the type of geometry feature that we are looking for
:type vtype: str
:param layer: the layer number that will be used
:type layer: int
:param generator: if True return a generator otherwise it return a
list of features
:type generator: bool
"""
if geo is None and vtype not in _GEOOBJ:
keys = "', '".join(sorted(_GEOOBJ.keys()))
raise ValueError("vtype not supported, use one of: '%s'" % keys)
Obj = _GEOOBJ[vtype] if geo is None else geo
ilist = Ilist()
libvect.Vect_cidx_find_all(self.c_mapinfo,
layer if layer else self.layer,
Obj.gtype, cat_id, ilist.c_ilist)
is2D = not self.is_3D()
if generator:
return (read_line(feature_id=v_id, c_mapinfo=self.c_mapinfo,
table=self.table, writeable=self.writeable,
is2D=is2D)
for v_id in ilist)
else:
return [read_line(feature_id=v_id, c_mapinfo=self.c_mapinfo,
table=self.table, writeable=self.writeable,
is2D=is2D)
for v_id in ilist]
def cat(self, cat_id, vtype, layer=None, generator=False, geo=None):
"""Return the geometry features with category == cat_id.
:param cat_id: the category number
:type cat_id: int
:param vtype: the type of geometry feature that we are looking for
:type vtype: str
:param layer: the layer number that will be used
:type layer: int
:param generator: if True return a generator otherwise it return a
list of features
:type generator: bool
"""
if geo is None and vtype not in _GEOOBJ:
keys = "', '".join(sorted(_GEOOBJ.keys()))
raise ValueError("vtype not supported, use one of: '%s'" % keys)
Obj = _GEOOBJ[vtype] if geo is None else geo
ilist = Ilist()
libvect.Vect_cidx_find_all(self.c_mapinfo,
layer if layer else self.layer,
Obj.gtype, cat_id, ilist.c_ilist)
is2D = not self.is_3D()
if generator:
return (read_line(feature_id=v_id, c_mapinfo=self.c_mapinfo,
table=self.table, writeable=self.writeable,
is2D=is2D)
for v_id in ilist)
else:
return [read_line(feature_id=v_id, c_mapinfo=self.c_mapinfo,
table=self.table, writeable=self.writeable,
is2D=is2D)
for v_id in ilist]
def viter(self, vtype, idonly=False):
"""Return an iterator of vector features
:param vtype: the name of type to query; the supported values are:
*areas*, *dblinks*, *faces*, *holes*, *islands*,
*kernels*, *line_points*, *lines*, *nodes*,
*update_lines*, *update_nodes*, *volumes*
:type vtype: str
:param idonly: variable to return only the id of features instead of
full features
:type idonly: bool
>>> cens = VectorTopo('census', mode='r')
>>> cens.open(mode='r')
>>> big = [area for area in cens.viter('areas')
... if area.alive() and area.area() >= 10000]
>>> big[:3]
[Area(5), Area(6), Area(13)]
to sort the result in a efficient way, use: ::
>>> from operator import methodcaller as method
>>> big.sort(key=method('area'), reverse=True) # sort the list
>>> for area in big[:3]:
... print area, area.area()
Area(2099) 5392751.5304
Area(2171) 4799921.30863
Area(495) 4055812.49695
>>> cens.close()
"""
if vtype in _GEOOBJ.keys():
if _GEOOBJ[vtype] is not None:
ids = (indx for indx in range(1, self.number_of(vtype) + 1))
if idonly:
return ids
return (_GEOOBJ[vtype](v_id=indx, c_mapinfo=self.c_mapinfo,
table=self.table,
writable=self.writable)
for indx in ids)
else:
keys = "', '".join(sorted(_GEOOBJ.keys()))
raise ValueError("vtype not supported, use one of: '%s'" % keys)