def Make_Discre_Road_Points(road_geo:ogr.Geometry,
start_points:dict,
seg_length:float):
'''
在road_geo上每隔seg_length取一个出发点（魔改版）
start_point将会是一个元组而不是Startpoint对象
(离散道路点, 前点, 后点)
'''
count = road_geo.GetPointCount()
total_length = road_geo.Length()
'''如果是在递归中seg_length比路的全长还要长，那就把路的最后一个点作为出发点'''
if seg_length >= total_length:
start_point_coord = road_geo.GetPoint_2D(count-1)
point_A_coord = road_geo.GetPoint_2D(count-2)
point_B_coord = road_geo.GetPoint_2D(count-1)
start_points[start_point_coord] = (point_A_coord, point_B_coord)
return
first_to_current_length = 0
temp_length = 0
temp_x1 = None
temp_y1 = None
temp_x2 = None
temp_y2 = None
'''计算当前线段的长度和累计长度'''
for index in range(count-1):
temp_x1 = road_geo.GetX(index)
temp_y1 = road_geo.GetY(index)
temp_x2 = road_geo.GetX(index+1)
temp_y2 = road_geo.GetY(index+1)
temp_length = math.sqrt( (temp_x1-temp_x2)**2 + (temp_y1-temp_y2)**2 )
first_to_current_length = first_to_current_length + temp_length
if seg_length < first_to_current_length:
break
'''这时从第零个点到第index+1个点的距离大于seg_length了'''
'''算出发点的坐标'''
len1 = seg_length - (first_to_current_length - temp_length)
start_point_x = (len1 / temp_length) * (temp_x2 - temp_x1) + temp_x1
start_point_y = (len1 / temp_length) * (temp_y2 - temp_y1) + temp_y1
if temp_x1 == 0:
print([temp_x1, temp_y1])
start_points[(start_point_x, start_point_y)] = ((temp_x1, temp_y1), (temp_x2, temp_y2))
'''给出发点后面的点做一个线的几何体，用来进行下一个递归'''
temp_road_geo = ogr.Geometry(ogr.wkbLineString)
temp_road_geo.AddPoint(start_point_x, start_point_y)
for i in range(index+1, count):
temp_x = road_geo.GetX(i)
temp_y = road_geo.GetY(i)
temp_road_geo.AddPoint(temp_x, temp_y)
Make_Discre_Road_Points(temp_road_geo, start_points, seg_length)
def Make_Start_Points_Road(road_geo:ogr.Geometry,
start_points:dict,
seg_length:float):
'''在road_geo上每隔seg_length取一个出发点'''
count = road_geo.GetPointCount()
total_length = road_geo.Length()
'''如果是在递归中seg_length比路的全长还要长，那就把路的最后一个点作为出发点'''
if seg_length >= total_length:
start_point = road_geo.GetPoint_2D(count-1)
start_points[start_point] = [road_geo.GetPoint_2D(count-2), road_geo.GetPoint_2D(count-1)]
#start_points = {出发点: [前驱点, 后继点]}
return
first_to_current_length = 0
temp_length = 0
temp_x1 = 0
temp_y1 = 0
temp_x2 = 0
temp_y2 = 0
'''计算当前线段的长度和累计长度'''
for index in range(count-1):
temp_x1 = road_geo.GetX(index)
temp_y1 = road_geo.GetY(index)
temp_x2 = road_geo.GetX(index+1)
temp_y2 = road_geo.GetY(index+1)
temp_length = math.sqrt( (temp_x1-temp_x2)**2 + (temp_y1-temp_y2)**2 )
first_to_current_length = first_to_current_length + temp_length
if seg_length < first_to_current_length:
pre_point = (temp_x1, temp_y1)
nex_point = (temp_x2, temp_y2)
break
'''这时从第零个点到第index+1个点的距离大于seg_length了'''
'''算出发点的坐标'''
len1 = seg_length - (first_to_current_length - temp_length)
start_point_x = (len1 / temp_length) * (temp_x2 - temp_x1) + temp_x1
start_point_y = (len1 / temp_length) * (temp_y2 - temp_y1) + temp_y1
start_points[(start_point_x, start_point_y)] = [pre_point, nex_point]
'''给出发点后面的点做一个线的几何体，用来进行下一个递归'''
temp_road_geo = ogr.Geometry(ogr.wkbLineString)
temp_road_geo.AddPoint(start_point_x, start_point_y)
for i in range(index+1, count):
temp_x = road_geo.GetX(i)
temp_y = road_geo.GetY(i)
temp_road_geo.AddPoint(temp_x, temp_y)
Make_Start_Points_Road(temp_road_geo, start_points, seg_length)
