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https://github.com/cran/RgoogleMaps
23 November 2023, 02:58:06 UTC
Revision ea4e2c0a951b77d8fd00969dbe7d699d3f877315 authored by Markus Loecher, Sense Networks on 20 July 2009, 00:00:00 UTC, committed by Gabor Csardi on 20 July 2009, 00:00:00 UTC 
version 1.1.5
1 parent d2c702a
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Tip revision: ea4e2c0a951b77d8fd00969dbe7d699d3f877315 authored by Markus Loecher, Sense Networks on 20 July 2009, 00:00:00 UTC
version 1.1.5
Tip revision: ea4e2c0
MaxZoom.R 
`MaxZoom` <-
function(latrange,lonrange, size = c(640,640)){
   SinPhi = sin(latrange * pi /180);
   normX = lonrange / 180;
   normY = (0.5 * log(abs((1 + SinPhi) / (1 -SinPhi) )) ) / pi;
   
   MaxZoom.lon <- floor(1 + log2(abs(size[1]/256/diff(normX))));
   MaxZoom.lat <- floor(1 + log2(abs(size[2]/256/diff(normY))));
   
   return(c(MaxZoom.lat=MaxZoom.lat,MaxZoom.lon=MaxZoom.lon))
 }
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