Creating a custom vertical coordinate system

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;


}

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

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;
}

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