python 은 방사선 법 을 실현 하여 도형 구역 내외 에 점 을 판단 합 니 다.

방사선 법 에 관 해 서 는 아래 의 이 블 로 그 를 참고 하여 매우 상세 하 게 쓸 수 있다.http://www.cnblogs.com/mazhenyu/p/3800638.html
다음은 제 가 python 으로 구현 한 코드 입 니 다.

# -*-encoding:utf-8 -*-
# file:class.py
#

"""
   
0	123.425658,41.774177
1	123.425843,41.774166
2	123.425847,41.774119
3	123.42693,41.774062
4	123.426943,41.774099
5	123.427118,41.774089
6	123.427066,41.773548
7	123.426896,41.773544
8	123.426916,41.773920
9	123.425838,41.773965
10	123.425804,41.773585
11	123.425611,41.773595

   
0	123.425649,41.77303
1	123.426656,41.772993
2	123.426611,41.772398
3	123.425605,41.772445
"""


class Point:
	lat = ''
	lng = ''
	
	def __init__(self,lat,lng):
		self.lat = lat #  
		self.lng = lng #  

	def show(self):
		print self.lat," ",self.lng


#               points1 
point0 = Point(123.425658,41.774177)
point1 = Point(123.425843,41.774166)
point2 = Point(123.425847,41.774119)
point3 = Point(123.42693,41.774062)
point4 = Point(123.426943,41.774099)
point5 = Point(123.427118,41.774089)
point6 = Point(123.427066,41.773548)
point7 = Point(123.426896,41.773544)
point8 = Point(123.426916,41.773920)
point9 = Point(123.425838,41.773961)
point10 = Point(123.425804,41.773585)
point11 = Point(123.425611,41.773595)

points1 = [point0,point1,point2,point3,
		   point4,point5,point6,point7,
		   point8,point9,point10,point11,
		  ]


#               points2 
point0 = Point(123.425649,41.77303)
point1 = Point(123.426656,41.772993)
point2 = Point(123.426611,41.772398)
point3 = Point(123.425605,41.772445)

points2 = [point0,point1,point2,point3]


'''
 points1 points2   points ,
points        
'''
points = [points1,points2]


'''
       ，     GPS  
         
        :123.4263790000,41.7740520000 123.42699,41.773592  
       :  123.4261550000,41.7726740000 123.42571,41.772499 123.425984,41.772919  
       :  123.4246270000,41.7738130000
          ，          ：123.4264060000,41.7737860000
'''
#lat = raw_input(please input lat)
#lng = raw_input(please input lng)
lat = 123.42699
lng = 41.773592
point = Point(lat,lng)

debug = raw_input("   debug")
if debug == '1':
	debug = True
else:
	debug = False

#     
def getPolygonBounds(points):
	length = len(points)
	#top down left right   point  
	top = down = left = right = points[0]
	for i in range(1,length):
		if points[i].lng > top.lng:
			top = points[i]
		elif points[i].lng < down.lng:
			down = points[i]
		else:
			pass
		if points[i].lat > right.lat:
			right = points[i]
		elif points[i].lat < left.lat:
			left = points[i]
    	else:
    		pass

	point0 = Point(left.lat,top.lng)
	point1 = Point(right.lat,top.lng)
	point2 = Point(right.lat,down.lng)
	point3 = Point(left.lat,down.lng)
	polygonBounds = [point0,point1,point2,point3]
 	return polygonBounds

#            
if debug:
	poly1 = getPolygonBounds(points[0])
	print "         ："
	for i in range(0,len(poly1)):
		poly1[i].show()	
	poly2 = getPolygonBounds(points[1])
	print "         ："
	for i in range(0,len(poly2)):
		poly2[i].show()	


#           
def isPointInRect(point,polygonBounds):
	if point.lng >= polygonBounds[3].lng and \
	   point.lng <= polygonBounds[0].lng and \
	   point.lat >= polygonBounds[3].lat and \
	   point.lat <= polygonBounds[2].lat:\
	   return True
	else:
		return False

#             
if debug:
	if(isPointInRect(point,poly1)):
		print "        "
	else:
		print "        "

	if(isPointInRect(point,poly2)):
		print "         "
	else:
		print "         "



#     ，              
def isPointInPolygon(point,points):
	#               
	Bound = Vertex = True
	count = 0
	precision = 2e-10
	
	#       
	polygonBounds = getPolygonBounds(points)

	#            ，    ，    false
	if not isPointInRect(point, polygonBounds):
		if debug:
			print "      "
		return False
	else:
		if debug:
			print "      "

	length = len(points)
	p = point
	p1 = points[0]
	for i in range(1,length):
		if p.lng == p1.lng and p.lat == p1.lat:
			if debug:
				print "Vertex1"
			return Vertex

		p2 = points[i % length]
		if p.lng == p2.lng and p.lat == p2.lat:
			if dubug:
				print "Vertex2"
			return Vertex

		if debug:	
			print i-1,i
			print "p:"
			p.show()
			print "p1:"
			p1.show()
			print "p2:"
			p2.show()

		if p.lng < min(p1.lng,p2.lng) or \
			p.lng > max(p1.lng,p2.lng) or \
			p.lat > max(p1.lat,p2.lat): 
			p1 = p2
			if debug:
				print "Outside"
			continue

		elif p.lng > min(p1.lng,p2.lng) and \
			p.lng < max(p1.lng,p2.lng):
			if p1.lat == p2.lat:
				if p.lat == p1.lat and \
					p.lng > min(p1.lng,p2.lng) and \
					p.lng < max(p1.lng,p2.lng):
					return Bound
				else:
					count = count + 1
					if debug:
						print "count1:",count
					continue
			if debug:
				print "into left or right"	  		

			a = p2.lng - p1.lng
			b = p1.lat - p2.lat
			c = p2.lat * p1.lng - p1.lat * p2.lng
			d = a * p.lat + b * p.lng + c
			if p1.lng < p2.lng and p1.lat > p2.lat or \
			   p1.lng < p2.lng and p1.lat < p2.lat:	
				if d < 0:
					count = count + 1
					if debug:
						print "count2:",count
				elif d > 0:
					p1 = p2
					continue
				elif abs(p.lng-d) < precision :
					return Bound
			else :	     	
				if d < 0:
					p1 = p2
					continue
				elif d > 0:
					count = count + 1
					if debug:
						print "count3:",count
				elif abs(p.lng-d) < precision :
					return Bound
		else:
			if p1.lng == p2.lng:
				if p.lng == p1.lng and \
					p.lat > min(p1.lat,p2.lat) and \
					p.lat < max(p1.lat,p2.lat):
				   return Bound
			else:
				p3 = points[(i+1) % length]
				if p.lng < min(p1.lng,p3.lng) or \
					p.lng > max(p1.lng,p3.lng):
					count = count + 2
					if debug:
						print "count4:",count
				else:
					count = count + 1
					if debug:
						print "count5:",count	 
		p1 = p2
	if count % 2 == 0 :
		return False
	else :
		return True



length = len(points)
flag = 0
for i in range(length):
	if isPointInPolygon(point,points[i]):
		print "          %d     " % (i+1)
		print "    i ，       ，       points  "
		break
	else:
		flag = flag + 1
	
if flag == length:
	print "   %d    " % (i+1)