Thanks Martin, Stacho, Ben, for your comments. Your assistance much appreciated. I have located my problem, simply an issue of the scope of namespaces. (The correct definition of a map object can be found in the Map Editor by double clicking on the object in the map tree pane on the side of the application window. - This inserts a select command in the thconfig file, so you may want to delete this to preserve the status of the thconfig file) In case anyone is trying to solve a similar problem, I've attached the previously submitted files, but with the errors corrected. So now I have a simple, scalable, file structure to easily plot a single survey, a cave composed of many surveys, or a system composed of many caves, at least that's what I'm hoping. (I've left the system data out of the attachment) Bruce