How to save and load color maps

Saving and loading color maps

Do the following steps to load a color map to a dataset:
  1. Cast the RasterDataset object into a RasterDatasetEdit object.
  2. Create a RasterColormap3 object.
  3. Load the .clr color map file.
  4. Alter the color map through the RasterDatasetEdit object.
Do the following steps to save a color map from a dataset:
  1. Cast the RasterDataset object into a RasterBandCollection object.
  2. Load a single raster band from the RasterBandCollection into a RasterBand object.
  3. Load the RasterBand.Colormap into a RasterColormap3 object.
  4. Call the RasterColormap3.SaveTo function to save the .clr file.

See the following code example:
[C#] 
// Load a color map from a .clr file to a raster dataset.
// .clr string example: "C:\colormap\MyColormap.clr"
public static void LoadColormap(IRasterDataset rasDs, string clrPathAndName)
{
    // Use the IRasterDatasetEdit interface to change the dataset color map.
    IRasterDatasetEdit rasEdit = (IRasterDatasetEdit)rasDs;
    // Create a color map.
    IRasterColormap3 rasColor3 = new RasterColormapClass();
    // Load the color map from the .clr file.
    rasColor3.LoadFrom(clrPathAndName);
    // Change the color map of the dataset. 
    rasEdit.AlterColormap((IRasterColormap)rasColor3);
}

// Save a color map from a dataset to a .clr file.
// .clr string example: "C:\colormap\MyNewColormap.clr"
public static void SaveColormap(IRasterDataset rasDs, string clrPathAndName)
{
    // Get the color map band of the dataset.
    IRasterBandCollection rasBC = (IRasterBandCollection)rasDs;
    IRasterBand rasBand = rasBC.Item(0);
    // Query interface (QI) to the IRasterColormap3 interface and save to a .clr file.
    IRasterColormap3 rasColor3 = (IRasterColormap3)rasBand.Colormap;
    rasColor3.SaveTo(clrPathAndName);
}
[VB.NET] 
' Load a color map from a .clr file to a raster dataset.
' .clr string example: "C:\colormap\MyColormap.clr"

Public Sub LoadColormap(ByVal rasDs As IRasterDataset, ByVal clrPathAndName As String)
    ' Use the IRasterDatasetEdit interface to change the dataset color map.
    Dim rasEdit As IRasterDatasetEdit
    rasEdit = rasDs
    ' Create a color map.
    Dim rasColor3 As IRasterColormap3
    rasColor3 = New RasterColormapClass
    ' Load the color map from the .clr file.
    rasColor3.LoadFrom(clrPathAndName)
    ' Change the color map of the dataset.
    rasEdit.AlterColormap(rasColor3)
End Sub

' Save a color map from a dataset to a .clr file.
' .clr string example: "C:\colormap\MyNewColormap.clr"

Public Sub SaveColormap(ByVal rasDs As IRasterDataset, ByVal clrPathAndName As String)
    ' Get the color map band from the dataset.
    Dim rasBC As IRasterBandCollection
    rasBC = rasDs
    Dim rasBand As IRasterBand
    rasBand = rasBC.Item(0)
    ' Query interface (QI) to the IRasterColormap3 interface and save to a .clr file.
    Dim rasColor3 As IRasterColormap3
    rasColor3 = rasBand.Colormap
    rasColor3.SaveTo(clrPathAndName)
End Sub





To use the code in this topic, reference the following assemblies in your Visual Studio project. In the code files, you will need using (C#) or Imports (VB .NET) directives for the corresponding namespaces (given in parenthesis below if different from the assembly name):
Development licensing Deployment licensing
ArcInfo ArcInfo
ArcEditor ArcEditor
ArcView ArcView
Engine Developer Kit Engine Runtime