public static void GetSuitableZoom(this Dataset dataset, ref int minZoom, ref int maxZoom)
{
string projectionStr = dataset.GetProjection();
double[] affineParas = new double[6];
dataset.GetGeoTransform(affineParas);
double xRes = affineParas[1];
double yRes = -affineParas[5];
double resolution = Math.Min(xRes, yRes);
double dWidth = Math.Max(dataset.RasterXSize * xRes, dataset.RasterYSize * yRes);
string projcs = null;
string geogcs = null;
using (OSGeo.OSR.SpatialReference srcSR = new OSGeo.OSR.SpatialReference(projectionStr))
{
projcs = srcSR.GetAttrValue("PROJCS", 0);
if (string.IsNullOrEmpty(projcs))
{
geogcs = srcSR.GetAttrValue("GEOGCS", 0);
}
}
bool isDegree = projcs == null && geogcs != null;
bool minZoomSeted = false;
bool maxZoomSeted = false;
for (int i = 0; i < 30; i++)
{
double tmpResolution = TileMatrix.GetResolution(isDegree, i);
if (!minZoomSeted)
{
if (dWidth / tmpResolution > 256)
{
if (i == 0)
{
minZoom = i;
}
else
{
minZoom = i - 1;
}
minZoomSeted = true;
}
}
if (!maxZoomSeted)
{
if (resolution >= tmpResolution)
{
maxZoom = i;
maxZoomSeted = true;
}
}
if (minZoomSeted && maxZoomSeted)
{
break;
}
}
}
public static List <double> GetResolutions(this TileMatrixSet tileMatrixSet, IEnumerable <string> tileMatrixIdentifiers)
{
List <double> resolutions = new List <double>();
bool isDegree = tileMatrixSet.GetIsDegreeByLocalDb();
foreach (var tileMatrixIdentifier in tileMatrixIdentifiers)
{
TileMatrix tileMatrix = tileMatrixSet.TileMatrix.FirstOrDefault(x => x.Identifier.Value == tileMatrixIdentifier);
if (tileMatrix != null)
{
double res = tileMatrix.GetResolution(isDegree);
resolutions.Add(res);
}
}
return(resolutions);
}
public static void GetSuitableZoom(this DataSource dataSource, ref int minZoom, ref int maxZoom)
{
string projcs = null;
string geogcs = null;
double xMin, yMin, xMax, yMax;
using (var layer = dataSource.GetLayerByIndex(0))
{
string layerName = layer.GetName();//todo 调试是否乱码
using (var spatialReference = layer.GetSpatialRef())
{
projcs = spatialReference.GetAttrValue("PROJCS", 0);
if (string.IsNullOrEmpty(projcs))
{
geogcs = spatialReference.GetAttrValue("GEOGCS", 0);
}
}
layer.GetExtent(out xMin, out yMin, out xMax, out yMax);
}
double dWidth = Math.Max(xMax - xMin, yMax - yMin);
bool isDegree = projcs == null && geogcs != null;
for (int i = 0; i < 30; i++)
{
double tmpResolution = TileMatrix.GetResolution(isDegree, i);
if (dWidth / tmpResolution > 256)
{
if (i == 0)
{
minZoom = i;
}
else
{
minZoom = i - 1;
}
break;
}
}
maxZoom = 19;
}