将球体从coord1旋转到coord2,coord3会在哪里? [英] Rotate a sphere from coord1 to coord2, where will coord3 be?
问题描述
我有三个坐标(lat,lon)在一个球体上。如果你想将整个球体从coord1旋转到coord2,那么coord3现在会被放置在哪里?
我一直在使用Great Circle(http:/ / /www.koders.com/python/fid0A930D7924AE856342437CA1F5A9A3EC0CAEACE2.aspx?s=coastline),但我创建了奇怪的结果,因为新计算的点在赤道一起组合在一起。这与我假设的方位角计算有关?
有人可能知道如何正确计算这个值吗?
编辑
我发现以下内容: http://www.uwgb.edu/dutchs/mathalgo/sphere0.htm
我想我现在需要计算笛卡尔坐标系(和0,0,0)中两点的旋转轴和旋转角度?我想这一定非常简单,与定义一架飞机并确定法线有关?有人可能知道我在哪里可以找到所需的方程式吗?
编辑2
Coord1和coord2是一个很棒的圈子。是否有一种简单的方法可以找到球体上大圆法线轴的位置?
编辑3
看起来我能解决它;)
http://articles.adsabs.harvard.edu//full/1953Metic...1...39L/0000039.000.html 做了诀窍。使用Visual Python我认为我现在已经解决了它:
<$ p $ <$ p
#为了地理目的而首先描述的旋转:http://www.uwgb.edu/dutchs/mathalgo/sphere0.htm
#http://stackoverflow.com/questions/6802577/ python-rotation-of-3d-vector
#http://vpython.org/
from visual import *
from math import *
import sys
def ll2cart(lon,lat):
#http://rbrundritt.wordpress.com/2008/10/14/conversion-between-spherical-and-cartesian-coordinates-systems/
x = cos(lat)* cos(lon)
y = cos(lat)* sin(lon )
z = sin(lat)
return x,y,z
def cart2ll(x,y,z):
#http://rbrundritt.wordpress .com / 2008/10/14 / conversion-between-spherical-and-cartesian-coordinates-systems /
r = sqrt((x ** 2)+(y ** 2)+(z ** 2) )
lat = asin(z / r)
lon = atan2(y,x)
return lon,lat
def distance(lon1,lat1,lon2, lat2):
#http://code.activestate.com/recipes/576779-calculating-distance-between-two-geographic-points/
#http://en.wikipedia.org/wiki / Haversine_formula
dlat = lat2 - lat1
dlon = lon2 - lon1
q = sin(dlat / 2)** 2 +(cos(lat1)* cos(lat2)*(sin(dlon / 2)** 2))
return 2 * atan2(sqrt(q),sqrt(1-q))
如果len(sys.argv)== 1:
sys.exit()
else:
csv = sys.argv [1]
#定义旋转的点A和B:
LonA =弧度( (float(sys.argv [4]))
float LatB = r adians(float(sys.argv [5]))
#A和B都是矢量
#交叉积AxB是旋转极点矢量P:
Ax,Ay, Az = ll2cart(LonA,LatA)
Bx,By,Bz = ll2cart(LonB,LatB)
A =矢量(Ax,Ay,Az)
B =矢量(Bx,By, Bz)
P = cross(A,B)
Px,Py,Pz = P
LonP,LatP = cart2ll(Px,Py,Pz)
#以弧度表示的旋转角度:
#http://code.activestate.com/recipes/576779-calculating-distance-between-two-geographic-points/
#http://en.wikipedia。 org / wiki / Haversine_formula
RotAngle =距离(LonA,LatA,LonB,LatB)
f = open(csv,r)
o = open(csv [: - 4 ($)
(lon,lat)= line.strip() .split(,)
#将被转换的点C:
LonC =弧度(float(lon))
LatC =弧度(float(lat))
#笛卡尔坐标点C:
Cx,Cy,Cz = ll2cart(LonC,LatC)
C =矢量(Cx,Cy,Cz)
#C旋转到D:
D =旋转(C,RotAngle,P)
Dx,Dy,Dz = D
LonD,LatD = cart2ll(Dx,Dy,Dz)
o.write(str(degrees(LonD))+,+ str(degrees(LatD))+\\\
)
I have three coordinates (lat,lon) on a sphere. If you would rotate the whole sphere from coord1 to coord2, where will coord3 now be located?
I've been trying this out in Python using Great Circle (http://www.koders.com/python/fid0A930D7924AE856342437CA1F5A9A3EC0CAEACE2.aspx?s=coastline) but I create strange results as the newly calculated points all group together at the equator. That must have something to do with the azimuth calculation I assume?
Does anyone maybe know how to calculate this correctly?
Thanks in advance!
EDIT
I found the following: http://www.uwgb.edu/dutchs/mathalgo/sphere0.htm
I guess I now need to calculate the rotation axis and the rotation angle from the two points in cartesian coords (and 0,0,0)? I guess this must be very simple, something to do with defining a plane and determining the normal line? Does someone maybe know where I can find the needed equations?
EDIT 2
Coord1 and coord2 make a great circle. Is there an easy way to find the location of the great circle normal axis on the sphere?
EDIT 3
Looks like I was able to solve it ;) http://articles.adsabs.harvard.edu//full/1953Metic...1...39L/0000039.000.html did the trick.
Using Visual Python I think I now have solved it:
# Rotation first described for geo purposes: http://www.uwgb.edu/dutchs/mathalgo/sphere0.htm
# http://stackoverflow.com/questions/6802577/python-rotation-of-3d-vector
# http://vpython.org/
from visual import *
from math import *
import sys
def ll2cart(lon,lat):
# http://rbrundritt.wordpress.com/2008/10/14/conversion-between-spherical-and-cartesian-coordinates-systems/
x = cos(lat) * cos(lon)
y = cos(lat) * sin(lon)
z = sin(lat)
return x,y,z
def cart2ll(x,y,z):
# http://rbrundritt.wordpress.com/2008/10/14/conversion-between-spherical-and-cartesian-coordinates-systems/
r = sqrt((x**2) + (y**2) + (z**2))
lat = asin(z/r)
lon = atan2(y, x)
return lon, lat
def distance(lon1, lat1, lon2, lat2):
# http://code.activestate.com/recipes/576779-calculating-distance-between-two-geographic-points/
# http://en.wikipedia.org/wiki/Haversine_formula
dlat = lat2 - lat1
dlon = lon2 - lon1
q = sin(dlat/2)**2 + (cos(lat1) * cos(lat2) * (sin(dlon/2)**2))
return 2 * atan2(sqrt(q), sqrt(1-q))
if len(sys.argv) == 1:
sys.exit()
else:
csv = sys.argv[1]
# Points A and B defining the rotation:
LonA = radians(float(sys.argv[2]))
LatA = radians(float(sys.argv[3]))
LonB = radians(float(sys.argv[4]))
LatB = radians(float(sys.argv[5]))
# A and B are both vectors
# The crossproduct AxB is the rotation pole vector P:
Ax, Ay, Az = ll2cart(LonA, LatA)
Bx, By, Bz = ll2cart(LonB, LatB)
A = vector(Ax,Ay,Az)
B = vector(Bx,By,Bz)
P = cross(A,B)
Px,Py,Pz = P
LonP, LatP = cart2ll(Px,Py,Pz)
# The Rotation Angle in radians:
# http://code.activestate.com/recipes/576779-calculating-distance-between-two-geographic-points/
# http://en.wikipedia.org/wiki/Haversine_formula
RotAngle = distance(LonA,LatA,LonB,LatB)
f = open(csv,"r")
o = open(csv[:-4] + "_translated.csv","w")
o.write(f.readline())
for line in f:
(lon, lat) = line.strip().split(",")
# Point C which will be translated:
LonC = radians(float(lon))
LatC = radians(float(lat))
# Point C in Cartesian coordinates:
Cx,Cy,Cz = ll2cart(LonC,LatC)
C = vector(Cx,Cy,Cz)
# C rotated to D:
D = rotate(C,RotAngle,P)
Dx,Dy,Dz = D
LonD,LatD = cart2ll(Dx,Dy,Dz)
o.write(str(degrees(LonD)) + "," + str(degrees(LatD)) + "\n")
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