How to check if spatial reference system is GCS or PCS?

Question

Hi,
for an application I have to get the unit of the coordinate system of a featureClass. (I'm using VBA)

What I do is: I take the layer with the FeatureClass. Then give the Layer to IGeoDataset. The Reference System of the dataset I pass to IGeographicCoordinateSystem or IProjectedCoordinateSystem. Finaly i get the unit from IUnit.

My problem is: Bevor I pass to IGeographicCoordinateSystem or IProjectedCoordinateSystem, I have to know, if it is a GCS or a PCS. Otherwise I get an error.

I didn't find out how I can check this before.

Does anyone of you have an idea?

MelitaKennedy · Answer

Hi,
for an application I have to get the unit of the coordinate system of a featureClass. (I'm using VBA)

What I do is: I take the layer with the FeatureClass. Then give the Layer to IGeoDataset. The Reference System of the dataset I pass to IGeographicCoordinateSystem or IProjectedCoordinateSystem. Finaly i get the unit from IUnit.

My problem is: Bevor I pass to IGeographicCoordinateSystem or IProjectedCoordinateSystem, I have to know, if it is a GCS or a PCS. Otherwise I get an error.

I didn't find out how I can check this before.

Does anyone of you have an idea?

You should be able to use something like this:    If TypeOf pSpatialReference Is IGeographicCoordinateSystem Then
        MsgBox "GeographicCoordinateSystem"
    End If
    
    If TypeOf pSpatialReference Is IUnknownCoordinateSystem Then
        MsgBox "UnknownCoordinateSystem"
    End If
    
    If TypeOf pSpatialReference Is IProjectedCoordinateSystem Then
        MsgBox "ProjectedCoordinateSystem"
    End If

Melita