def SnapToNode(e, n, tresh, vectMap):
"""Find nearest node to click coordinates (within given threshold)"""
if not haveCtypes:
return None
vectMap, mapSet = ParseMapStr(vectMap)
openedMap = pointer(vectlib.Map_info())
ret = vectlib.Vect_open_old(openedMap, c_char_p(vectMap), c_char_p(mapSet))
if ret == 1:
vectlib.Vect_close(openedMap)
if ret != 2:
return None
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 False
return e, n
def node(self, point, maxdist):
"""Find the nearest node around a specific point.
:param point: The point to search
:type point: grass.pygrass.vector.geometry.Point
:param maxdist: The maximum search distance around the point
:type maxdist: float
:return: A grass.pygrass.vector.geometry.Node if found or None
This methods uses libvect.Vect_find_node()()
Examples:
>>> from grass.pygrass.vector import VectorTopo
>>> from grass.pygrass.vector.geometry import Point
>>> test_vect = VectorTopo(test_vector_name)
>>> test_vect.open('r')
# Find nearest node
>>> points = (Point(10,0), Point(10,4), Point(14,0))
>>> result = []
>>> for point in points:
... f = test_vect.find_by_point.node(point=point, maxdist=1)
... if f:
... result.append(f)
>>> result
[Node(2), Node(1), Node(6)]
>>> test_vect.find_by_point.node(point=Point(20,20), maxdist=0)
>>> test_vect.close()
"""
node_id = libvect.Vect_find_node(
self.c_mapinfo,
point.x,
point.y,
point.z if point.z else 0,
float(maxdist),
int(not point.is2D),
)
if node_id:
return Node(
v_id=node_id,
c_mapinfo=self.c_mapinfo,
table=self.table,
writeable=self.writeable,
)
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