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Creating a custom vertical coordinate system (ArcObjects .NET 10.4 SDK)
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Creating a custom vertical coordinate system


Summary
This topic shows two methods to define a custom vertical coordinate system (VCS).

About creating a custom vertical coordinate system

The ISpatialReferenceFactory interface allows you to create the Datum, VerticalDatum, and LinearUnit component parts. These components can also be created using a similar Define method available on their classes.
  • The following code example creates a gravity-related VCS that uses a vertical datum:
[C#] 
private IVerticalCoordinateSystem CreateVerticalCoordinateSystem()
{

    // Set up the SpatialReferenceEnvironment.
    // SpatialReferenceEnvironment is a singleton object and needs to use the Activator class.
    Type factoryType=Type.GetTypeFromProgID(
        "esriGeometry.SpatialReferenceEnvironment");
    System.Object obj=Activator.CreateInstance(factoryType);
    ISpatialReferenceFactory3 spatialReferenceFactory=obj as
        ISpatialReferenceFactory3;

    // Creates a gravity-related vertical datum.
    IVerticalDatum verticalDatum=spatialReferenceFactory.CreateVerticalDatum((int)
        esriSRVerticalDatumType.esriSRVertDatum_Taranaki);

    // Because a VCS can be based upon Datum or VerticalDatum, IHVDatum is used 
    // when defining a VCS.
    IHVDatum hvDatum=verticalDatum as IHVDatum;
    ILinearUnit linearUnit=spatialReferenceFactory.CreateUnit((int)
        esriSRUnitType.esriSRUnit_Meter)as ILinearUnit;

    // The direction is set to –1 and the VerticalShift is set to 40.
    IVerticalCoordinateSystemEdit verticalCoordinateSystemEdit=new
        VerticalCoordinateSystemClass();
    object name="New VCoordinateSystem";
    object alias="VCoordinateSystem alias";
    object abbreviation="abbr";
    object remarks="Test for options";
    object usage="New Zealand";
    object hvDatumObject=hvDatum as object;
    object unitObject=linearUnit as object;
    object verticalShift=40 as object;
    object positiveDirection= - 1 as object;

    verticalCoordinateSystemEdit.Define(ref name, ref alias, ref abbreviation, ref
        remarks, ref usage, ref hvDatumObject, ref unitObject, ref verticalShift,
        ref positiveDirection);
    IVerticalCoordinateSystem verticalCoordinateSystem =
        verticalCoordinateSystemEdit as IVerticalCoordinateSystem;

    return verticalCoordinateSystem;


}
[VB.NET] 
Private Function CreateVerticalCoordinateSystem() As IVerticalCoordinateSystem
    
    ' Set up the SpatialReferenceEnvironment.
    ' SpatialReferenceEnvironment is a singleton object and needs to use the Activator class.
    
    Dim factoryType As Type=Type.GetTypeFromProgID("esriGeometry.SpatialReferenceEnvironment")
    Dim spatialReferenceFactory As ISpatialReferenceFactory3=CType(Activator.CreateInstance(factoryType), ISpatialReferenceFactory3)
    
    ' Creates a gravity-related vertical datum.
    Dim verticalDatum As IVerticalDatum=spatialReferenceFactory.CreateVerticalDatum(CInt(esriSRVerticalDatumType.esriSRVertDatum_Taranaki))
    
    ' Because a VCS can be based upon Datum or VerticalDatum, IHVDatum is used
    ' when defining a VCS.
    Dim hvDatum As IHVDatum=TryCast(verticalDatum, IHVDatum)
    Dim linearUnit As ILinearUnit=CType(spatialReferenceFactory.CreateUnit(CInt(esriSRUnitType.esriSRUnit_Meter)), ILinearUnit)
    
    ' The direction is set to –1 and the VerticalShift is set to 40.
    Dim verticalCoordinateSystemEdit As IVerticalCoordinateSystemEdit=New VerticalCoordinateSystemClass()
    Dim Name As Object="New VCoordinateSystem"
    
    ' Note: Alias is a reserved keyword in VB .NET. To use it as a variable name, encase it in brackets [ ].
    
    Dim [Alias] As Object="VCoordinateSystem alias"
    Dim abbreviation As Object="abbr"
    Dim remarks As Object="Test for options"
    Dim usage As Object="New Zealand"
    Dim hvDatumObject As Object=TryCast(hvDatum, Object)
    Dim unitObject As Object=TryCast(linearUnit, Object)
    Dim verticalShift As Object=TryCast(40, Object)
    Dim positiveDirection As Object=TryCast( -1, Object)
    
    verticalCoordinateSystemEdit.Define(Name, [Alias], abbreviation, remarks, usage, hvDatumObject, unitObject, verticalShift, positiveDirection)
    Dim verticalCoordinateSystem As IVerticalCoordinateSystem=TryCast(verticalCoordinateSystemEdit, IVerticalCoordinateSystem)
    
    Return verticalCoordinateSystem
    
End Function
  • The following code example creates an ellipsoid-based VCS:
[C#] 
private IVerticalCoordinateSystem CreateEllipsoidBasedVerticalCoordinateSystem()
{
    // Set up the SpatialReferenceEnvironment.
    // SpatialReferenceEnvironment is a singleton object and needs to use the Activator class.
    Type t=Type.GetTypeFromProgID("esriGeometry.SpatialReferenceEnvironment");
    System.Object obj=Activator.CreateInstance(t);
    ISpatialReferenceFactory3 spatialReferenceFactory=obj as
        ISpatialReferenceFactory3;

    // Creates an ellipsoid-based datum.
    IDatum datum=spatialReferenceFactory.CreateDatum((int)
        esriSRDatumType.esriSRDatum_WGS1984);

    // Because a VCS can be based upon Datum or VerticalDatum, IHVDatum is used 
    // when defining a VCS.
    IHVDatum hvDatum=datum as IHVDatum;
    ILinearUnit linearUnit=spatialReferenceFactory.CreateUnit((int)
        esriSRUnitType.esriSRUnit_Foot)as ILinearUnit;

    //Direction is again positive down, while the vertical shift is 0.4839.
    IVerticalCoordinateSystemEdit verticalCoordinateSystemEdit=new
        VerticalCoordinateSystemClass();
    object name="WGS84 vcs";
    object alias="WGS84 ellipsoid";
    object abbreviation="w84 3d";
    object remarks="WGS84 ell-based vcs";
    object usage="everywhere!";
    object hvDatumObject=hvDatum as object;
    object unitObject=linearUnit as object;
    object verticalShift=0.4839 as object;
    object positiveDirection= - 1 as object;

    verticalCoordinateSystemEdit.Define(ref name, ref alias, ref abbreviation, ref
        remarks, ref usage, ref hvDatumObject, ref unitObject, ref verticalShift,
        ref positiveDirection);
    IVerticalCoordinateSystem verticalCoordinateSystem =
        verticalCoordinateSystemEdit as IVerticalCoordinateSystem;

    return verticalCoordinateSystem;
}
[VB.NET] 
Private Function CreateEllipsoidBasedVerticalCoordinateSystem() As IVerticalCoordinateSystem
    
    ' Set up the SpatialReferenceEnvironment.
    ' SpatialReferenceEnvironment is a singleton object and needs to use the Activator class.
    
    Dim t As Type=Type.GetTypeFromProgID("esriGeometry.SpatialReferenceEnvironment")
    Dim obj As System.Object=Activator.CreateInstance(t)
    Dim spatialReferenceFactory As ESRI.ArcGIS.Geometry.ISpatialReferenceFactory3=obj
    
    ' Creates an ellipsoid-based datum.
    Dim datum As IDatum=spatialReferenceFactory.CreateDatum(CInt(esriSRDatumType.esriSRDatum_WGS1984))
    
    ' Because a VCS can be based upon Datum or VerticalDatum, IHVDatum is used
    ' when defining a VCS.
    Dim hvDatum As IHVDatum=TryCast(datum, IHVDatum)
    Dim linearUnit As ILinearUnit=CType(spatialReferenceFactory.CreateUnit(CInt(esriSRUnitType.esriSRUnit_Foot)), ILinearUnit)
    
    ' Direction is again positive down, while the vertical shift is 0.4839.
    Dim verticalCoordinateSystemEdit As IVerticalCoordinateSystemEdit=New VerticalCoordinateSystemClass()
    Dim Name As Object="WGS84 vcs"
    
    ' Note: Alias is a reserved keyword in VB .NET. To use it as a variable name, encase it in brackets [ ].
    Dim [Alias] As Object="WGS84 ellipsoid"
    Dim abbreviation As Object="w84 3d"
    Dim remarks As Object="WGS84 ell-based vcs"
    Dim usage As Object="everywhere!"
    Dim hvDatumObject As Object=TryCast(hvDatum, Object)
    Dim unitObject As Object=TryCast(linearUnit, Object)
    Dim verticalShift As Object=TryCast(0.4839, Object)
    Dim positiveDirection As Object=TryCast( -1, Object)
    
    verticalCoordinateSystemEdit.Define(Name, [Alias], abbreviation, remarks, usage, hvDatumObject, unitObject, verticalShift, positiveDirection)
    Dim verticalCoordinateSystem As IVerticalCoordinateSystem=TryCast(verticalCoordinateSystemEdit, IVerticalCoordinateSystem)
    
    Return verticalCoordinateSystem
    
End Function


See Also:

Creating a predefined vertical coordinate system



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