1 #我用两个算法都测试了，
 2 import csv
 3 #第一个测试算法
 4 def isInside(lng,lat):
 5 #我的6个顶点，下边有图
 6     Points=[{"Lat":30.2641546,"Lng":120.1530812},
 7             {"Lat":30.2527681,"Lng":120.1593446},
 8             {"Lat":30.1983117,"Lng":120.1460286},
 9             {"Lat":30.1789750,"Lng":120.0805163},
10             {"Lat":30.2288384,"Lng":120.0630072},
11             {"Lat":30.2510622,"Lng":120.0956252}
12 
13             ]
14     minlong=120.063007
15     maxlong=120.159344
16     minlat=30.178975
17     maxlat=30.264154
18 #如果被测试点小于最小值，或者大于最大经纬度，那么肯定不在多边形内，直接return false
19     if (lng<minlong or lng>maxlong or lat<minlat or lat>maxlat):
20         return False;
21     count = 6
22 
23     result = False;
24 
25     j=count-1
26     for i in range(0,count):
27 
28         p1 = Points[i];
29         p2 = Points[j];
30 
31         if(p1["Lat"] < lat and  p2["Lat"] >= lat or  p2["Lat"] < lat and  p1["Lat"] >= lat):
32 
33             if(p1["Lng"] + (lat - p1["Lat"]) / (p2["Lat"] - p1["Lat"]) * (p2["Lng"] - p1["Lng"]) < lng):
34                 result = not result;
35         j = i;
36     return result;
37 #第二个测试算法
38  # /**
39  #   * @description 射线法判断点是否在多边形内部
40  #   * @param {Object} p 待判断的点，格式：{ x: X坐标, y: Y坐标 }
41  #   * @param {Array} poly 多边形顶点，数组成员的格式同 p
42  #   * @return {String} 点 p 和多边形 poly 的几何关系
43  #   */
44 
45 def rayCasting(x,y):
46     poly=[{"y":30.2641546,"x":120.1530812},
47             {"y":30.2527681,"x":120.1593446},
48             {"y":30.1983117,"x":120.1460286},
49             {"y":30.1789750,"x":120.0805163},
50             {"y":30.2288384,"x":120.0630072},
51             {"y":30.2510622,"x":120.0956252}
52 
53             ]
54     px=x
55     py=y
56     flag=False
57     N=6
58     j=N-1
59     for i in range (0,N):
60         sx= poly[i]["x"]
61         sy=poly[i]["y"]
62         tx=poly[j]["x"]
63         ty=poly[j]["y"]
64         if ((sx==px and sy==py) or (tx==px and ty==py) ):
65             return "on"
66         if ((sy<py and ty >= py) or (sy>=py and ty < py)):
67             x=sx+(py-sy)*(tx-sx)/(ty-sy)
68             if (x==px):
69                 return "on"
70             if (x>px):
71                 flag=not flag
72         j=i
73 
74     return flag
75 
76 
77 
78 with open("nearwestlake_state0_2.csv","r") as fr:
79     fr=csv.reader(fr)
80     for row in fr:
81         res=isInside(float(row[1]),float(row[2]))#row[1]是经度,row[2]是纬度
82         print(res)
83         if res==True:
84             fw=open("nearwestlake_2.csv","a")
85             fw.write(','.join(row)+'\n')
86             fw.close()
87             
88