XY2LatLon {RgoogleMaps} | R Documentation |
The function XY2LatLon(MyMap, X,Y,zoom) computes the coordinate transformation from map tile coordinates to lat/lon given a map object.
XY2LatLon(MyMap, X, Y, zoom)
MyMap |
map object |
X |
latitude values to transform |
Y |
longitude values to transform |
zoom |
optional zoom level. If missing, taken from MyMap |
properly scaled and centered (with respect to the center of MyMap
) coordinates
lon |
longitude |
lat |
latitude |
Markus Loecher, Sense Networks <markus@sensenetworks.com>
#quick test: zoom=12;MyMap <- list(40,-120,zoom); LatLon <- c(lat = 40.0123, lon = -120.0123); Rcoords <- LatLon2XY.centered(MyMap,LatLon["lat"],LatLon["lon"]) newLatLon <- XY2LatLon(MyMap, Rcoords$newX, Rcoords$newY) max(abs(newLatLon - LatLon)); #more systematic: for (zoom in 2:10){ cat("zoom: ", zoom, "\n"); MyMap <- list(40,-120,zoom); LatLon <- c(lat = runif(1,-80,80), lon = runif(1,-170,170)); Rcoords <- LatLon2XY.centered(MyMap,LatLon["lat"],LatLon["lon"]) newLatLon <- XY2LatLon(MyMap, Rcoords$newX, Rcoords$newY) if(max(abs(newLatLon - LatLon)) > 0.0001) print(rbind(LatLon, newLatLon)); }