Orthogonal Projection of Meridian or Parallel
Orthogonal Projection Meridian or Parallel
merid(lon, lat1=-90, lat2=90, lam0=0, phi1=41, R=1, by=1) paral(lat, lon1=-180 , lon2=180, lam0=0, phi1=41, R=1, by=1)
lon
: merid starting Longitude, degreeslat
: paral starting Latitude, degreeslam0
: origin Longitude, degreesphi1
: origin Latitude, degreesR
: Radiusby
: increment in degreeslat1
: merid starting Latitude, degreeslat2
: merid ending Latitude, degreeslon1
: paral starting Longitude, degreeslon2
: paral ending Longitude, degreesRetruns points along a meridian running through lat, lon with a projection based on lam0 phi.
list of x-y values for plotting
Snyder, John P., Map Projections- a working manual, USGS, Professional Paper, 1987.
Jonathan M. Leesjonathan.lees@unc.edu
ortho.proj
olat = 0 olon = 0 tlat = 23 tlon = 30 M = merid(tlon, lat1=tlat, olon, olat, 1) R = 1 phi1=40 GLOBE.ORTH(20, phi1, 1,plotmap=FALSE) M1 = merid(20, lat1=20, lat2=40, phi1=phi1, lam0=olat, R=1, by=1) P2 = paral(40, lon1=20 , lon2=40, lam0=olat, phi1=phi1, R=1, by=1) M2 = merid(40, lat1=40, lat2=20, phi1=phi1, lam0=olat, R=1, by=1) P1 = paral(20, lon1=40 , lon2=20, lam0=olat, phi1=phi1, R=1, by=1) polygon(c(M1$x, P2$x, M2$x, P1$x), c(M1$y, P2$y, M2$y, P1$y), col=rgb(.8, .8, 1))
Useful links