Description Usage Arguments Value Author(s) See Also Examples
The function XY2LatLon(MyMap, X,Y,zoom) computes the coordinate transformation from map tile coordinates to lat/lon given a map object.
1 | 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 |
properly scaled and centered (with respect to the center of MyMap
) coordinates
lon |
longitude |
lat |
latitude |
Markus Loecher
LatLon2XY Tile2R
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | #quick test:
zoom=12;MyMap <- list(40,-120,zoom, url="google");
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, url="google");
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));
}
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