static WebMercatorUtility()
{
MaxAllowableLatitude = 85.05112877822864;
MaxIsometricLatitude = MapProjects.GeodeticLatitudeToIsometricLatitude(MaxAllowableLatitude, FirstEccentricity);
MinIsometricLatitude = MapProjects.GeodeticLatitudeToIsometricLatitude(-MaxAllowableLatitude, FirstEccentricity);
ZoomLevels = Enumerable.Range(0, 24).Reverse().Select(i => new ZoomScale(i, 591657550.50 / Math.Pow(2, i))).ToList();
minZoomLevel = 1;
maxZoomLevel = 22;
//ZoomLevels = new List<ZoomScale>();
//24: 591657550.50 / 2 ^ (24 - 1) = 70.5311
//23: 591657550.50 / 2 ^ (23 - 1) = 141.0622
//22: 591657550.50 / 2 ^ (22 - 1) = 282.1243
//21: 591657550.50 / 2 ^ (21 - 1) = 564.2486
//20: 591657550.50 / 2 ^ (20 - 1) = 1128.4972
//TO SUPPORT CORRECT ZOOM LEVEL
//ZoomLevels.Add(new ZoomScale(20, double.Epsilon));
//ZoomLevels.Add(new ZoomScale(19, 1128.497220));
//ZoomLevels.Add(new ZoomScale(18, 2256.994440));
//ZoomLevels.Add(new ZoomScale(17, 4513.988880));
//ZoomLevels.Add(new ZoomScale(16, 9027.977761));
//ZoomLevels.Add(new ZoomScale(15, 18055.955520));
//ZoomLevels.Add(new ZoomScale(14, 36111.911040));
//ZoomLevels.Add(new ZoomScale(13, 72223.822090));
//ZoomLevels.Add(new ZoomScale(12, 144447.644200));
//ZoomLevels.Add(new ZoomScale(11, 288895.288400));
//ZoomLevels.Add(new ZoomScale(10, 577790.576700));
//ZoomLevels.Add(new ZoomScale(9, 1155581.153000));
//ZoomLevels.Add(new ZoomScale(8, 2311162.307000));
//ZoomLevels.Add(new ZoomScale(7, 4622324.614000));
//ZoomLevels.Add(new ZoomScale(6, 9244649.227000));
//ZoomLevels.Add(new ZoomScale(5, 18489298.450000));
//ZoomLevels.Add(new ZoomScale(4, 36978596.910000));
//ZoomLevels.Add(new ZoomScale(3, 73957193.820000));
//ZoomLevels.Add(new ZoomScale(2, 147914387.600000));
//ZoomLevels.Add(new ZoomScale(1, 295828775.300000));
//ZoomLevels.Add(new ZoomScale(0, 591657550.500000));
}
public static Point LatLonToImageNumber(double geocentricLatitude, double geocentricLongitude, int zoom)
{
var tempLongitude = geocentricLongitude % 360;
if (tempLongitude > 180)
{
tempLongitude -= 180;
}
else
{
tempLongitude += 180;
}
//This is not the total number of images. It's the number of images per row/column
int numberOfImages = (int)Math.Pow(2, zoom);
var xUnit = 360.0 / numberOfImages;
var yUnit = (MaxIsometricLatitude - MinIsometricLatitude) / numberOfImages;
var columnNumber = Math.Floor(tempLongitude / xUnit);
var isoY = MapProjects.GeodeticLatitudeToIsometricLatitude(geocentricLatitude, FirstEccentricity);
var rowNumber = isoY / yUnit;
if (rowNumber < 0)
{
rowNumber = Math.Ceiling(-rowNumber) + Math.Ceiling(MaxIsometricLatitude / yUnit) - 1;
}
else
{
rowNumber = Math.Ceiling(MaxIsometricLatitude / yUnit) - Math.Ceiling(rowNumber);
}
return(new Point(columnNumber, rowNumber));
}