20 lines
587 B
R
20 lines
587 B
R
LatLong2XY <-
|
|
function(lat_v,lon_v,R=6.371*10^6){
|
|
th0 = min(lon_v)
|
|
th1 = max(lon_v)
|
|
ph0 = min(lat_v)
|
|
ph1 = max(lat_v)
|
|
d1 = 2*pi*R*((ph1-ph0)*2*pi/360)/(2*pi)
|
|
d2 = 2*pi*(R*sin(pi/2-ph1*2*pi/360))*((th1-th0)*2*pi/360)/(2*pi)
|
|
d3 = 2*pi*(R*sin(pi/2-ph0*2*pi/360))*((th1-th0)*2*pi/360)/(2*pi)
|
|
x_v=rep(0,length(lon_v))
|
|
y_v=rep(0,length(lat_v))
|
|
for(i in 1:length(lat_v)){
|
|
w1=(lat_v[i]-ph0)/(ph1-ph0)
|
|
w2=(lon_v[i]-th0)/(th1-th0)
|
|
x_v[i]=w1*abs(d3-d2)/2+w2*(d3*(1-w1)+d2*w1)
|
|
y_v[i]=w1*d1*sin(acos(abs((d3-d2)/(2*d1))))
|
|
}
|
|
return(list("x_v"=x_v,"y_v"=y_v))
|
|
}
|