def read(self, feature_id):
"""Return a geometry object given the feature id. ::
>>> mun = VectTopo('boundary_municp_sqlite')
>>> mun.open()
>>> feature1 = mun.read(0) #doctest: +ELLIPSIS
Traceback (most recent call last):
...
ValueError: The index must be >0, 0 given.
>>> feature1 = mun.read(1)
>>> feature1
Boundary(v_id=1)
>>> feature1.length()
1415.3348048582038
>>> mun.read(-1)
Centoid(649102.382010, 15945.714502)
>>> len(mun)
8707
>>> mun.read(8707)
Centoid(649102.382010, 15945.714502)
>>> mun.read(8708) #doctest: +ELLIPSIS
Traceback (most recent call last):
...
IndexError: Index out of range
>>> mun.close()
..
"""
if feature_id < 0: # Handle negative indices
feature_id += self.__len__() + 1
if feature_id >= (self.__len__() + 1):
raise IndexError('Index out of range')
if feature_id > 0:
c_points = ctypes.pointer(libvect.line_pnts())
c_cats = ctypes.pointer(libvect.line_cats())
ftype = libvect.Vect_read_line(self.c_mapinfo, c_points, c_cats,
feature_id)
if GV_TYPE[ftype]['obj'] is not None:
return GV_TYPE[ftype]['obj'](v_id=feature_id,
c_mapinfo=self.c_mapinfo,
c_points=c_points,
c_cats=c_cats)
else:
raise ValueError('The index must be >0, %r given.' % feature_id)
def GetNearestNodeCat(e, n, layer, tresh, vectMap):
if not haveCtypes:
return -2
vectMapName, mapSet = ParseMapStr(vectMap)
openedMap = pointer(vectlib.Map_info())
ret = vectlib.Vect_open_old(openedMap,
c_char_p(encode(vectMapName)),
c_char_p(encode(mapSet)))
if ret == 1:
vectlib.Vect_close(openedMap)
if ret != 2:
return -1
nodeNum = vectlib.Vect_find_node(openedMap,
c_double(e),
c_double(n),
c_double(0),
c_double(tresh),
vectlib.WITHOUT_Z)
if nodeNum > 0:
e = c_double(0)
n = c_double(0)
vectlib.Vect_get_node_coor(openedMap,
nodeNum,
byref(e),
byref(n),
None) # z
e = e.value
n = n.value
else:
vectlib.Vect_close(openedMap)
return -1
box = vectlib.bound_box()
List = POINTER(vectlib.boxlist)
List = vectlib.Vect_new_boxlist(c_int(0))
box.E = box.W = e
box.N = box.S = n
box.T = box.B = 0
vectlib.Vect_select_lines_by_box(
openedMap, byref(box),
vectlib.GV_POINT, List)
found = 0
dcost = 0
Cats = POINTER(vectlib.line_cats)
Cats = vectlib.Vect_new_cats_struct()
cat = c_int(0)
for j in range(List.contents.n_values):
line = List.contents.id[j]
type = vectlib.Vect_read_line(openedMap, None, Cats, line)
if type != vectlib.GV_POINT:
continue
if vectlib.Vect_cat_get(Cats, c_int(layer), byref(cat)):
found = 1
break
if found:
return cat.value
return -1
def read(self):
"""Read and set the coordinates of the centroid from the vector map,
using the centroid_id and calling the Vect_read_line C function"""
libvect.Vect_read_line(self.c_mapinfo, self.c_points, self.c_cats,
self.id)