Python 从公里(km)转换为十进制度数
使用Python 从公里(km)转换为十进制度数,python,distance,spatial,haversine,Python,Distance,Spatial,Haversine,使用scipy.KDTree执行一些快速的最近邻搜索。我正在使用KDTree.query\u ball\u point(pnt,r=some\u distance)进行搜索 由于我的点是横向的,所以要搜索的半径值(某些距离)必须以十进制度数为单位(我相信)。如果我想让用户能够访问此功能,我希望该距离以公里、米、英里等为单位 使用pythonlibs,将以km为单位的距离转换为十进制度数的最佳方法是什么?我用的是numpy,scipy和PySAL 感谢您的帮助, Louis经典计算来自: 距离 这
scipy.KDTree
执行一些快速的最近邻搜索。我正在使用KDTree.query\u ball\u point(pnt,r=some\u distance)
进行搜索
由于我的点是横向的,所以要搜索的半径值(某些距离
)必须以十进制度数为单位(我相信)。如果我想让用户能够访问此功能,我希望该距离以公里、米、英里等为单位
使用pythonlibs,将以km为单位的距离转换为十进制度数的最佳方法是什么?我用的是numpy,scipy和PySAL
感谢您的帮助,
Louis经典计算来自:
距离
这使用了“哈弗森”公式来计算两点之间的大圆距离——即地球表面上的最短距离——给出两点之间的“如同乌鸦一样”距离(当然,忽略任何山丘!)
哈弗森
公式:
a = sin²(Δφ/2) + cos(φ1).cos(φ2).sin²(Δλ/2)
c = 2.atan2(√a, √(1−a))
d = R.c
其中φ为纬度,λ为经度,R为地球半径(平均半径=6371km)
请注意,角度需要以弧度为单位才能传递到trig函数
当然,你可以根据海里和公里的定义做一个非常粗略的近似:
海里(符号M、NM或nmi)是一种长度单位,即沿任何子午线(海平面)测量的约一分钟的纬度弧,或赤道处约一分钟的经度弧。根据国际协议,它被精确设置为1852米(约6076英尺)
这可能不是一个直接的解决方案,但更多的是一个参考。我以前试过使用哈弗森公式,但是用它来计算最近的n个邻居的集合,当用它来计算数千个点时,它变得长得令人无法忍受 因此,我创建了一个散列类(或映射?),可以将其放入二叉树中以允许快速搜索。它不适用于距离,但适用于角度(横向、纵向) find函数的工作原理是找到树中最近的点,然后沿着树向上走,直到找到n个节点 geocode.py:
units = [(31-q, 180.0/(2 ** q)) for q in range(32)]
def bit_sum(bits):
return sum([2**bit for bit in bits])
class gpshash(object):
def __init__(self, longitude = None, latitude = None, **kwargs):
if(kwargs):
if(kwargs.has_key("longitude ") and kwargs.has_key("latitude ")):
self.longitude = geohash(degrees=kwargs["degrees"])
self.latitude = geohash(degrees=kwargs["hash"])
else:
if(longitude == None or latitude == None):
self.longitude = geohash(degrees=0)
self.latitude = geohash(degrees=0)
else:
self.longitude = geohash(degrees=longitude)
self.latitude = geohash(degrees=latitude)
long_hash = self.longitude.bin_hash
lat_hash = self.latitude.bin_hash
hash_str = ""
if(len(long_hash) == len(lat_hash)):
for i in range(len(long_hash)):
hash_str += (long_hash[i]+lat_hash[i])
self.bin_hash = hash_str
def __str__(self):
return "%s, %s" % (str(self.longitude.hash), str(self.latitude.hash))
def __repr__(self):
return str("<gpshash long: %f lat: %f>" % (self.longitude.degrees, self.latitude.degrees))
def __eq__(self, other):
if(isinstance(self, gpshash) and isinstance(other, gpshash)):
return (((self.longitude._hash ^ other.longitude._hash) == 0) and ((self.latitude._hash ^ other.latitude._hash) == 0))
else:
return False
class geohash(object):
def __init__(self, degrees = 0, **kwargs):
if(kwargs):
if(kwargs.has_key("degrees")):
self.degrees = kwargs["degrees"] % 360
self._hash = self.encode()
elif(kwargs.has_key("hash")):
self._hash = kwargs["hash"] % ((2 << 31) - 1)
self.degrees = self.decode()
else:
self.degrees = degrees % 360
self._hash = self.encode()
def __str__(self):
return str(self.hash)
def __repr__(self):
return str("<geohash degrees: %f hash: %s>" % (self.degrees, self.hash))
def __add__(self, other):
return geohash(hash=(self._hash + other._hash))
def __sub__(self, other):
return geohash(hash=(self._hash - other._hash))
def __xor__(self, other):
return geohash(hash=(self._hash ^ other._hash))
def __eq__(self, other):
if(isinstance(self, geohash) and isinstance(other, geohash)):
return ((self._hash ^ other._hash) == 0)
else:
return False
def encode(self):
lesser = filter(lambda (bit, angle): self.degrees >= angle, units)
combined = reduce(lambda (bits, angles), (bit, angle): (bits+[bit], angles + angle) if((angles + angle) <= self.degrees) else (bits, angles), lesser, ([], 0))
return bit_sum(combined[0])
def decode(self):
lesser = filter(lambda (bit, angle): self._hash>= (2 ** bit), units)
combined = reduce(lambda (bits, angles), (bit, angle): (bits+[bit], angles + angle) if((bit_sum(bits+[bit])) <= self._hash) else (bits, angles), lesser, ([], 0))
return combined[1]
@property
def hash(self):
self._hash = self.encode()
return "%08x" % self._hash
@property
def inv_hash(self):
self._inv_hash = self.decode()
return self._inv_hash
@property
def bin_hash(self):
self._bin_hash = bin(self._hash)[2:].zfill(32)
return self._bin_hash
class gdict(object):
'''
Base Geo Dictionary
Critical Components taken from Python26\Lib\UserDict.py
'''
__slots__ = ["parent", "left", "right", "hash_type"]
hash_type = None
def __init__(self, ihash=None, iparent=None):
def set_helper(iparent, cur_hex, hex_list):
ret_bin_tree = self.__class__(None, iparent)
if(hex_list):
ret_bin_tree.set_child(cur_hex, set_helper(ret_bin_tree, hex_list[0], hex_list[1:]))
return ret_bin_tree
elif(cur_hex):
ret_bin_tree.set_child(cur_hex, ihash)
return ret_bin_tree
self.parent = self
self.left = None
self.right = None
if(iparent != None):
self.parent = iparent
if(isinstance(ihash, self.hash_type)):
ilist = list(ihash.bin_hash)
if(len(ilist) > 1):
ret_bin_tree = set_helper(self, ilist[1], ilist[2:])
if(ret_bin_tree):
self.set_child(ilist[0], ret_bin_tree)
def set_child(self, istr, ichild):
if(istr == "0"):
self.left = ichild
elif(istr == "1"):
self.right = ichild
def get_child(self, istr):
if(istr == "0"):
return self.left
elif(istr == "1"):
return self.right
else:
return ""
def __repr__(self):
def repr_print_helper(ibin_tree, fmt_str = "", depth = 1):
if(not isinstance(ibin_tree, self.__class__)):
fmt_str += "\n"
fmt_str += ("%%%ds" % (depth)) % ""
fmt_str += ibin_tree.__repr__()
else:
if((ibin_tree.left != None and ibin_tree.right == None) or (ibin_tree.left == None and ibin_tree.right != None)):
if(ibin_tree.left != None):
fmt_str += "0"
fmt_str = repr_print_helper(ibin_tree.left, fmt_str, depth + 1)
elif(ibin_tree.right != None):
fmt_str += "1"
fmt_str = repr_print_helper(ibin_tree.right, fmt_str, depth + 1)
else:
if(ibin_tree.left != None):
fmt_str += "\n"
fmt_str += ("%%%ds" % (depth - 1)) % ""
fmt_str += "0"
fmt_str = repr_print_helper(ibin_tree.left, fmt_str, depth + 1)
if(ibin_tree.right != None):
fmt_str += "\n"
fmt_str += ("%%%ds" % (depth - 1)) % ""
fmt_str += "1"
fmt_str = repr_print_helper(ibin_tree.right, fmt_str, depth + 1)
return fmt_str
return repr_print_helper(self)
def find(self, ihash, itarget = 1):
class flat(list):
pass
def find_helper_base(iparent, ibin_tree, ihash):
ret_find = None
if(isinstance(ibin_tree, self.hash_type)):
ret_find = iparent
elif(len(ihash) > 0):
if(ibin_tree.get_child(ihash[0])):
ret_find = find_helper_base(ibin_tree, ibin_tree.get_child(ihash[0]), ihash[1:])
else:
ret_find = ibin_tree
return ret_find
def up_find(iflat, iparent, ibin_tree, ibias = "0"):
if((ibin_tree != iparent) and (len(iflat) < itarget)):
if(iparent.left):
if(len(iflat) >= itarget):
return
if(iparent.left != ibin_tree):
down_find(iflat, iparent.left, ibias)
if(iparent.right):
if(len(iflat) >= itarget):
return
if(iparent.right != ibin_tree):
down_find(iflat, iparent.right, ibias)
up_find(iflat, ibin_tree.parent.parent, ibin_tree.parent, ibias)
def down_find(iflat, ibin_tree, ibias = "0"):
if(len(iflat) >= itarget):
return
elif(isinstance(ibin_tree, self.hash_type)):
iflat += [ibin_tree]
else:
if(ibias == "1"):
if(ibin_tree.left):
down_find(iflat, ibin_tree.left, ibias)
if(ibin_tree.right):
down_find(iflat, ibin_tree.right, ibias)
else:
if(ibin_tree.right):
down_find(iflat, ibin_tree.right, ibias)
if(ibin_tree.left):
down_find(iflat, ibin_tree.left, ibias)
if(isinstance(ihash, self.hash_type)):
flatter = flat()
hasher = ihash.bin_hash
base = find_helper_base(self, self.get_child(hasher[0]), hasher[1:])
if(base):
down_find(flatter, base)
bias = flatter[0].bin_hash[0]
up_find(flatter, base.parent, base, bias)
return list(flatter)
def merge(self, from_bin_tree):
def merge_helper(to_bin_tree, from_bin_tree):
if(isinstance(from_bin_tree, self.__class__)):
if(from_bin_tree.left != None):
if(to_bin_tree.left != None):
merge_helper(to_bin_tree.left, from_bin_tree.left)
else:
from_bin_tree.left.parent = to_bin_tree
to_bin_tree.left = from_bin_tree.left
elif(from_bin_tree.right != None):
if(to_bin_tree.right != None):
merge_helper(to_bin_tree.right, from_bin_tree.right)
else:
from_bin_tree.right.parent = to_bin_tree
to_bin_tree.right = from_bin_tree.right
merge_helper(self, from_bin_tree)
class geodict(gdict):
'''
Geo Dictionary
'''
hash_type = geohash
def __init__(self, ihash=None, iparent=None):
gdict.__init__(self, ihash, iparent)
class gpsdict(gdict):
'''
GPS Dictionary
'''
hash_type = gpshash
def __init__(self, ihash=None, iparent=None):
gdict.__init__(self, ihash, iparent)
if(__name__ == "__main__"):
gpses = \
[
gpshash(90, 90),
gpshash(68, 24),
gpshash(144, 60),
gpshash(48, 91),
gpshash(32, 105),
gpshash(32, 150),
gpshash(167, 20),
gpshash(49, 116),
gpshash(81, 82),
gpshash(63, 79),
gpshash(129, 76)
]
base_dict = gpsdict()
for cur_hash in gpses:
base_dict.merge(gpsdict(cur_hash ))
print "All locations added:"
print base_dict
print ""
print "Trying to find 3 nearest points to:"
to_find = gpshash(60, 20)
print to_find.__repr__()
found = base_dict.find(to_find, 3)
print ""
print "Found the following:"
for x in found:
print x.__repr__()
units=[(31-q,180.0/(2**q))表示范围内的q(32)]
定义位和(位):
返回和([2**bit for bit in bit])
类gpshash(对象):
定义初始值(self,经度=None,纬度=None,**kwargs):
如果(kwargs):
如果(kwargs.有_键(“经度”)和kwargs.有_键(“纬度”):
self.longitude=geohash(度=kwargs[“度”])
self.latitude=geohash(度=kwargs[“hash”])
其他:
如果(经度==无或纬度==无):
self.longitude=geohash(度=0)
self.latitude=geohash(度=0)
其他:
self.longitude=geohash(度=经度)
self.latitude=geohash(度=纬度)
long\u hash=self.longitude.bin\u hash
lat_hash=self.latitude.bin_hash
hash_str=“”
如果(len(long_hash)=len(lat_hash)):
对于范围内的i(len(long_hash)):
hash_str+=(long_hash[i]+lat_hash[i])
self.bin\u hash=hash\u str
定义(自我):
返回“%s,%s%”(str(self.longitude.hash)、str(self.latitude.hash))
定义报告(自我):
返回str(“%(self.longitude.degrees,self.latitude.degrees))
定义(自身、其他):
如果(isinstance(self,gpshash)和isinstance(other,gpshash)):
返回(((self.longitude.\u hash^ other.longitude.\u hash)==0)和((self.latitude.\u hash^ other.latitude.\u hash)==0))
其他:
返回错误
类geohash(对象):
定义初始值(自身,度=0,**kwargs):
如果(kwargs):
如果(kwargs.有_键(“度”):
self.degrees=kwargs[“度”]%360
self.\u hash=self.encode()
elif(kwargs.has_key(“散列”):
self._hash=kwargs[“hash”]%(2=角度,单位)
组合=减少(λ(位,角度),(位,角度):(位+位,角度+角度)如果((角度+角度)=(2**位),单位)
组合=减少(λ(位,角度),(位,角度):(位+[位],角度+角度)如果((位+和(位+[位])1):
ret_bin_tree=set_helper(self,ilist[1],ilist[2:])
如果(ret_bin_树):
self.set_child(ilist[0],ret_bin_树)
def set_子项(自身、istr、ichild):
如果(istr==“0”):
self.left=ichild
elif(istr==“1”):
self.right=ichild
def get_子项(自身、istr):
如果(istr==“0”):
自左返回
elif(istr==“1”):
回归自我权利
其他:
返回“”
定义报告(自我):
def repr_print_helper(ibin_树,fmt_str=“”,深度=1):
如果(不存在(ibin_树,自身类):
fmt_str+=“\n”
fmt_str+=(“%%%ds”%(深度))%
fmt_str+=ibin_树
其他:
如果((ibin_tree.left!=None和ibin_tree.right==None)或(ibin_tree.left==None和ibin_tree.right!=None)):
如果(ibin_tree.left!=无):
fmt_str+=“0”
fmt_str=repr_print_helper(ibin_tree.left,fmt_str,depth+1)
elif(ibin_tree.right!=无):
fmt_str+=“1”
fmt_str=repr_print_helper(ibin_tree.right,fmt_str,depth+1)
其他:
如果(ibin_tree.left!=无):
fmt_str+=“\n”
fmt_str+=(“%%%ds”%(深度-1))”
fmt_str+=“0”
fmt_str=repr_print_helper(ibin_tree.left,fmt_str,depth+1)
如果(ibin_tree.right!=无):
fmt_str+=“\n”
fmt_str+=(“%%%ds”%(深度-1))”
fmt_str+=“1”