How to perform mensuration on an image service

public static void Measure(IImageServer4 imageServer)
{
    //Define building bottom.
    IPoint fromPoint = new PointClass();
    fromPoint.X =  - 117.29944857;
    fromPoint.Y = 34.15586888;
    fromPoint.SpatialReference = imageServer.ServiceInfo.SpatialReference;

    //Define building top.
    IPoint toPoint = new PointClass();
    toPoint.X =  - 117.29940048;
    toPoint.Y = 34.15589815;
    toPoint.SpatialReference = imageServer.ServiceInfo.SpatialReference;

    //Measure height.
    IImageServerMeasureResult result = imageServer.Measure(fromPoint, toPoint, null,
        null, esriMensurationOperation.esriMensurationHeightFromBaseAndTop);
    Console.WriteLine("{0} +/- {1} {2}", (Double)result.Measurement.GetProperty(
        "Height"), (Double)result.Measurement.GetProperty("HeightUncertainty"), 
        (string)result.Measurement.GetProperty("LinearUnit"));
}

Public Shared Sub Measure(ByVal imageServer As IImageServer4)
'Define building bottom.
Dim fromPoint As IPoint = New PointClass()
fromPoint.X = -117.29944857
fromPoint.Y = 34.15586888
fromPoint.SpatialReference = imageServer.ServiceInfo.SpatialReference

'Define building top.
Dim toPoint As IPoint = New PointClass()
toPoint.X = -117.29940048
toPoint.Y = 34.15589815
toPoint.SpatialReference = imageServer.ServiceInfo.SpatialReference

'Measure height.
Dim result As IImageServerMeasureResult = imageServer.Measure(fromPoint, toPoint, Nothing, Nothing, esriMensurationOperation.esriMensurationHeightFromBaseAndTop)
Console.WriteLine("{0} +/- {1} {2}", DirectCast(result.Measurement.GetProperty("Height"), Double), DirectCast(result.Measurement.GetProperty("HeightUncertainty"), Double), DirectCast(result.Measurement.GetProperty("LinearUnit"), String))
End Sub