Arcgis Engine栅格渲染（唯一值）IRasterUniqueValueRenderer

最新推荐文章于 2025-05-11 00:11:02 发布

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本文详细介绍了如何使用ArcGIS Engine API在栅格数据上实现自定义的唯一值渲染器，包括创建颜色映射、设置渲染器属性、添加值和标签等关键步骤。

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参照官方代码后改造而成，有没有属性表都支持。

public static bool UniqueValueRenderer(IColorRamp colorRamp, IRasterLayer rasterLayer, string renderfiled="Value")
        {
            try
            {
                IRasterUniqueValueRenderer uniqueValueRenderer = new RasterUniqueValueRendererClass();                
                IRasterRenderer pRasterRenderer = uniqueValueRenderer as IRasterRenderer;
                pRasterRenderer.Raster = rasterLayer.Raster;
                pRasterRenderer.Update();
                IUniqueValues uniqueValues = new UniqueValuesClass();
                IRasterCalcUniqueValues calcUniqueValues = new RasterCalcUniqueValuesClass();
                calcUniqueValues.AddFromRaster(rasterLayer.Raster, 0, uniqueValues);//iBand=0
                IRasterRendererUniqueValues renderUniqueValues = uniqueValueRenderer as IRasterRendererUniqueValues;
                renderUniqueValues.UniqueValues = uniqueValues;
                uniqueValueRenderer.Field = renderfiled;
                colorRamp.Size = uniqueValues.Count;

                uniqueValueRenderer.HeadingCount = 1;
                uniqueValueRenderer.set_Heading(0, "All Data Value");
                uniqueValueRenderer.set_ClassCount(0, uniqueValues.Count);
                bool pOk;
                colorRamp.CreateRamp(out pOk);
                IRasterRendererColorRamp pRasterRendererColorRamp = uniqueValueRenderer as IRasterRendererColorRamp;
                pRasterRendererColorRamp.ColorRamp = colorRamp;
                for (int i = 0; i < uniqueValues.Count; i++)
                {
                    uniqueValueRenderer.AddValue(0, i, uniqueValues.get_UniqueValue(i));
                    uniqueValueRenderer.set_Label(0, i, uniqueValues.get_UniqueValue(i).ToString());
                    IFillSymbol fs=new SimpleFillSymbol();
                    fs.Color = colorRamp.get_Color(i);
                    uniqueValueRenderer.set_Symbol(0, i, fs as ISymbol);
                }
                pRasterRenderer.Update();
                rasterLayer.Renderer = pRasterRenderer;
            }
            catch(Exception ex)
            {
                return false;
            }
            return true;
        }

官方代码如下：

http://resources.esri.com/help/9.3/arcgisengine/dotnet/77da7a38-c696-407d-b73c-ddb36def6032.htm

public IRasterRenderer UnqueValueRenderer
  (ESRI.ArcGIS.Geodatabase.IRasterDataset rasterDataset)
{
  try
  {
    //Get the raster attribute table and the size of the table.
    IRaster2 raster = (IRaster2)rasterDataset.CreateDefaultRaster();
    ITable rasterTable = raster.AttributeTable;
    if (rasterTable == null)
    {
      return null;
    }
    int tableRows = rasterTable.RowCount(null);
    //Create colors for each unique value.
    IRandomColorRamp colorRamp = new RandomColorRampClass();
    colorRamp.Size = tableRows;
    colorRamp.Seed = 100;
    bool createColorRamp;
    colorRamp.CreateRamp(out createColorRamp);
    if (createColorRamp == false)
    {
      return null;
    }
    //Create a unique value renderer.
    IRasterUniqueValueRenderer uvRenderer = new RasterUniqueValueRendererClass

()
      ;
    IRasterRenderer rasterRenderer = (IRasterRenderer)uvRenderer;
    rasterRenderer.Raster = rasterDataset.CreateDefaultRaster();
    rasterRenderer.Update();
    //Set the renderer properties.
    uvRenderer.HeadingCount = 1;
    uvRenderer.set_Heading(0, "All Data Value");
    uvRenderer.set_ClassCount(0, tableRows);
    uvRenderer.Field = "Value"; //Or any other field in the table.
    IRow row;
    ISimpleFillSymbol fillSymbol;
    for (int i = 0; i < tableRows; i++)
    {
      row = rasterTable.GetRow(i);
      uvRenderer.AddValue(0, i, Convert.ToByte(row.get_Value(1))); 
        // Assuming the raster is 8-bit.
      uvRenderer.set_Label(0, i, Convert.ToString(row.get_Value(1)));
      fillSymbol = new SimpleFillSymbolClass();
      fillSymbol.Color = colorRamp.get_Color(i);
      uvRenderer.set_Symbol(0, i, (ISymbol)fillSymbol);
    }
    return rasterRenderer;
  }
  catch (Exception ex)
  {
    System.Diagnostics.Debug.WriteLine(ex.Message);
    return null;
  }
}