/// <summary>
/// 获取等高线
/// </summary>
/// <returns></returns>
static OSGeo.OGR.Layer getDZX_()
{
StaticTools.msgLine("createDZX...");
//分析数据源
double noDataValue; //无效值
int hasDataValue; //0不使用无效值,1使用无效值
dsmDataset.GetRasterBand(1).GetNoDataValue(out noDataValue, out hasDataValue);
//WKT
string wkt = dsmDataset.GetProjectionRef();
OSGeo.OSR.SpatialReference srs = wkt == "" ? null : new OSGeo.OSR.SpatialReference(wkt);
//图像值属性，最大值、最小值、平均值
double min, max, mean, std;
dsmDataset.GetRasterBand(1).GetStatistics(0, 1, out min, out max, out mean, out std);
//计算每级线的值，加0.5是确保取到最接近的整数，不被四舍五入
int count = Convert.ToInt32((max - min) / jianG + 0.5);
double[] shu = new double[count];
for (int i = 0; i < count; i++)
{
shu[i] = min + jianG * i;
}
//创建空的SHP，准备塞入数据
shpDataSet.deleteLayerByName("dzx");
OSGeo.OGR.Layer dzxLayer = shpDataSet.CreateLayer("dzx", srs, OSGeo.OGR.wkbGeometryType.wkbMultiLineString, null);
//必须有这两个字段，函数要往里塞值，其实没毛用
OSGeo.OGR.FieldDefn fieldDf0 = new OSGeo.OGR.FieldDefn("LID", OSGeo.OGR.FieldType.OFTInteger);
OSGeo.OGR.FieldDefn fieldDf1 = new OSGeo.OGR.FieldDefn("EVE", OSGeo.OGR.FieldType.OFTReal);
dzxLayer.CreateField(fieldDf0, 1); //ID
dzxLayer.CreateField(fieldDf1, 1); //Value
//Band(1), 间隔, 起始高度, 分段数量, 分段值数组, 是否有无效值, 无效值, 预置图层. ID字段, 高度值字段, null , null
OSGeo.GDAL.Gdal.ContourGenerate(dsmDataset.GetRasterBand(1), jianG, min, count, shu, hasDataValue, noDataValue, dzxLayer, 0, 1, null, null);
if (dzxLayer.GetFeatureCount(0) > 0)
{
return(dzxLayer);
}
else
{
return(null);
}
}
