How to perform a geodata transformation on a raster (ArcObjects .NET 10.4 SDK)

Summary

A geodata transformation is a mathematical model that performs geometric transformation on a raster. The geodata transformation consists of concrete classes, such as PolynomialXform, RPCXform, AdjustXform, and so on.

Performing a geodata transformation on a raster

To perform a geodata transformation on a raster, follow these steps:

Set the transformation on the raster using the IRaster2 interface.
Set the cell size.
Set the output extent.

See the following code example:

[C#]

public static void SetGeodataXformAndSaveAs(IRaster2 raster, IGeodataXform xform)
{
    //Get the original extent and cell size of the raster.
    IRasterProps rasterProp=raster as IRasterProps;
    IEnvelope extent=rasterProp.Extent;
    IPnt cellSize=rasterProp.MeanCellSize();
    double xCell=cellSize.X;
    double yCell=cellSize.Y;

    //Set the xform on the raster.
    raster.GeodataXform=xform;

    //Transform the cell size first, then the extent; the sequence matters.
    xform.TransformCellsize(esriTransformDirection.esriTransformForward, ref xCell,
        ref yCell, extent);
    xform.TransformExtent(esriTransformDirection.esriTransformForward, extent);

    //Put the transformed extent and cell size on the raster and save as.
    rasterProp.Extent=extent;
    rasterProp.Width=Convert.ToInt32(extent.Width / xCell);
    rasterProp.Height=Convert.ToInt32(extent.Height / yCell);

    //Save the raster.
    ISaveAs saveAs=raster as ISaveAs;
    saveAs.SaveAs(@"c:\temp\image1.img", null, "IMAGINE Image");
}

[VB.NET]

Public Sub SetGeodataXformAndSaveAs(ByVal raster As IRaster2, ByVal xform As IGeodataXform)
    
    'Get the original extent and cell size of the raster.
    Dim rasterProp As IRasterProps=TryCast(raster, IRasterProps)
    Dim extent As IEnvelope=rasterProp.Extent
    Dim cellSize As IPnt=rasterProp.MeanCellSize()
    Dim xCell As Double=cellSize.X
    Dim yCell As Double=cellSize.Y
    
    'Set the xform on the raster.
    raster.GeodataXform=xform
    
    'Transform the cell size first, then the extent; the sequence matters.
    xform.TransformCellsize(esriTransformDirection.esriTransformForward, xCell, yCell, extent)
    xform.TransformExtent(esriTransformDirection.esriTransformForward, extent)
    
    'Put the transformed extent and cell size on the raster and save as.
    rasterProp.Extent=extent
    rasterProp.Width=Convert.ToInt32(extent.Width / xCell)
    rasterProp.Height=Convert.ToInt32(extent.Height / yCell)
    
    'Save the raster.
    Dim saveAs As ISaveAs=TryCast(raster, ISaveAs)
    saveAs.SaveAs("c:\temp\image1.img", Nothing, "IMAGINE Image")
    
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
ArcGIS for Desktop Basic	ArcGIS for Desktop Basic
ArcGIS for Desktop Standard	ArcGIS for Desktop Standard
ArcGIS for Desktop Advanced	ArcGIS for Desktop Advanced
Engine Developer Kit	Engine