private static TileProjection getTileProjection(ProjectionType projType, CoordinateExtent extent, int?minZoomLevel, int?maxZoomLevel)
{
// 默认投影信息
Projection projection = new Projection(projType);
// 瓦片投影
TileProjection tileProjection = new TileProjection();
tileProjection.ProjType = projType;
if (extent == null)
{
extent = projection.GetDefaultCoordinateExtent();
}
else
{
extent = projection.CorrectCoordianteExtent(extent);
}
tileProjection.CoordExtent = extent;
if (minZoomLevel == null || !projection.CheckZoomLevel(minZoomLevel.Value))
{
tileProjection.MinZoomLevel = projection.MIN_ZOOM_LEVEL;
}
else
{
tileProjection.MinZoomLevel = minZoomLevel.Value;
}
if (maxZoomLevel == null || !projection.CheckZoomLevel(maxZoomLevel.Value))
{
tileProjection.MaxZoomLevel = projection.MAX_ZOOM_LEVEL;
}
else
{
tileProjection.MaxZoomLevel = maxZoomLevel.Value;
}
// TileExtent: key,level;value,TileExtent
tileProjection.TileExtentCollection = new Dictionary <int, TileExtent>();
// 遍历所有Level
for (int i = tileProjection.MinZoomLevel; i <= tileProjection.MaxZoomLevel; i++)
{
TileExtent tileExtent = new TileExtent();
tileExtent.ProjType = projType;
tileExtent.ZoomLevel = i;
// 计算当前范围
double originX = projection.MIN_X;
double originY = projection.MAX_Y;
tileExtent.MinRowIndex = Convert.ToInt32(
Math.Floor(
(originY - extent.MaxY) / (projection.TILE_SIZE * projection.GetZoomResolution(i))
));
tileExtent.MinColumnIndex = Convert.ToInt32(
Math.Floor(
(originX - extent.MinX) / (projection.TILE_SIZE * projection.GetZoomResolution(i))
));
tileExtent.MaxRowIndex = Convert.ToInt32(
Math.Ceiling(
(originY - extent.MinY) / (projection.TILE_SIZE * projection.GetZoomResolution(i))
));
tileExtent.MaxColumnIndex = Convert.ToInt32(
Math.Ceiling(
(originX - extent.MaxX) / (projection.TILE_SIZE * projection.GetZoomResolution(i))
));
tileExtent.RowNumber = tileExtent.MaxRowIndex - tileExtent.MinRowIndex + 1;
tileExtent.ColumnNumber = tileExtent.MaxColumnIndex - tileExtent.MinColumnIndex + 1;
// 添加到集合
tileProjection.TileExtentCollection.Add(i, tileExtent);
}
return(tileProjection);
}