Overview
From AutoCAD Map 3D Geospatial Platform API
A map is composed of layers, where each layer represents data from a feature source.
AutoCAD Map 3D and Autodesk MapGuide differ in some of the ways they handle map layers. Because MapGuide is a web-based mapping product, it must coordinate layer display based on information from the client and the server. AutoCAD Map 3D can handle all layer display directly from the application.
A layer (AcMapLayer object), has a LayerDefinition property that points to a layer definition in the resource repository. The layer definition content is XML that conforms to the LayerDefinition.xsdLayerDefinition.xsd schema. Among other elements, it contains a ResourceId element that identifies the feature source for the layer.