private Extent ToSphericalMercator(Extent orgExent)
{
var p1 = ToSphericalMercator(orgExent.XLow, orgExent.YLow);
var p2 = ToSphericalMercator(orgExent.XHigh, orgExent.YHigh);
return new Extent
{
XLow = p1.X,
YLow = p1.Y,
XHigh = p2.X,
YHigh = p2.Y
};
}
private Extent GetTileExtent(int x, int y, int zoom)
{
var tiles = (long)Math.Pow(2, zoom);
var circumference = TileSize * tiles;
var radius = circumference / (2 * Math.PI);
var extent = new Extent
{
XLow = XToLong((x - (tiles / 2.0)) * TileSize, radius),
YLow = YToLat(((tiles / 2.0) - y - 1) * TileSize, radius),
XHigh = XToLong((x - (tiles / 2.0) + 1) * TileSize, radius),
YHigh = YToLat(((tiles / 2.0) - y) * TileSize, radius)
};
if (Version == "1.3.0" && Epsg == 4326)
{
var newTypeExtent = new Extent
{
XLow = extent.YLow,
YLow = extent.XLow,
XHigh = extent.YHigh,
YHigh = extent.XHigh
};
extent = newTypeExtent;
}
if (Epsg == 3857 || Epsg == 900913 )
{
extent = ToSphericalMercator(extent);
}
return extent;
}