/// <summary>
/// 计算单张瓦片层级号的四支范围
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <param name="z"></param>
/// <returns></returns>
public static RectExtent GetTileExtent(int x, int y, int z)
{
Coord leftUpCoord = TileToWorldPos(x, y, z);
Coord rightDownCoord = TileToWorldPos(x + 1, y + 1, z);
RectExtent result = new RectExtent();
result.LeftUp = leftUpCoord;
result.Width = rightDownCoord.Lon - leftUpCoord.Lon;
result.Height = leftUpCoord.Lat - rightDownCoord.Lat;
return(result);
}
/// <summary>
/// 获取计算范围内的坐标
/// </summary>
/// <param name="calculateRect"></param>
/// <param name="zoom"></param>
/// <returns></returns>
public static Rectangle GetTileSeqsFromGeoExtent(RectExtent calculateRect, int zoom)
{
var leftUpP = WorldToTilePos(calculateRect.LeftUp.Lon, calculateRect.LeftUp.Lat, zoom);
var rightDownP = WorldToTilePos(calculateRect.RightDown.Lon, calculateRect.RightDown.Lat, zoom);
Rectangle result = new Rectangle();
result.Location = leftUpP;
result.Width = rightDownP.X - leftUpP.X;
result.Height = rightDownP.Y - leftUpP.Y;
return(result);
}
public static RectExtent EnvelopeToRectExtent(Envelope envelope)
{
RectExtent result = new RectExtent();
result.LeftUp = new Coord()
{
Lon = envelope.MinX, Lat = envelope.MaxY
};
result.Width = envelope.MaxX - envelope.MinX;
result.Height = envelope.MaxY - envelope.MinY;
return(result);
}
public static Geometry RectExtentToGeometry(RectExtent rectExtent)
{
Geometry ring = new Geometry(wkbGeometryType.wkbLinearRing);
ring.AddPoint_2D(rectExtent.LeftUp.Lon, rectExtent.LeftUp.Lat);
ring.AddPoint_2D(rectExtent.RightUp.Lon, rectExtent.RightUp.Lat);
ring.AddPoint_2D(rectExtent.RightDown.Lon, rectExtent.RightDown.Lat);
ring.AddPoint_2D(rectExtent.LeftDown.Lon, rectExtent.LeftDown.Lat);
ring.AddPoint_2D(rectExtent.LeftUp.Lon, rectExtent.LeftUp.Lat);
Geometry geometry = new Geometry(wkbGeometryType.wkbPolygon);
geometry.AddGeometry(ring);
return(geometry);
}
/// <summary>
/// 生成矢量切片
/// </summary>
/// <param name="srcLayer"></param>
/// <param name="rectExtent"></param>
/// <param name="format"></param>
/// <param name="saveFile"></param>
/// <param name="trgSrs">输出投影</param>
/// <param name="simplifyDiff">设置两个最小相似点的距离，越大点越容易合并。值类型与图层数据类型（经纬度或长度）保持一致</param>
/// <param name="createEmptyFile">设置两个最小相似点的距离，越大点越容易合并。值类型与图层数据类型（经纬度或长度）保持一致</param>
/// <returns></returns>
public static bool CreateTileFile(Layer srcLayer, RectExtent rectExtent,
string format, string saveFile, OSGeo.OSR.SpatialReference trgSrs, double simplifyDiff, bool createEmptyFile)
{
Geometry rectG = CommonUtils.RectExtentToGeometry(rectExtent);
srcLayer.SetSpatialFilter(rectG);
int featureCount = srcLayer.GetFeatureCount(1);
if (featureCount == 0 && !createEmptyFile)
{
return(true);
}
OSGeo.OGR.Driver driver = Ogr.GetDriverByName(format);
var trgDataset = driver.CreateDataSource(saveFile, null);
var trgLayerName = System.IO.Path.GetFileNameWithoutExtension(saveFile);
var trgLayer = trgDataset.CreateLayer(trgLayerName, trgSrs, srcLayer.GetGeomType(), null);
Feature feature = null;
int flag;
srcLayer.ResetReading();
while ((feature = srcLayer.GetNextFeature()) != null)
{
var geometry = feature.GetGeometryRef();
//Douglas - Peucker algorithm算法进行抽稀
if (simplifyDiff > 0)
{
var simGeo = geometry.SimplifyPreserveTopology(simplifyDiff);
feature.SetGeometry(simGeo);
}
flag = trgLayer.CreateFeature(feature);
}
return(true);
}
public void SetCalculateRect(RectExtent rect)
{
CalculateRect = rect;
}
