The MapGuide API is designed to be used in a web server environment, and is available in PHP, Java, and .NET. AutoCAD Map 3D is designed to be used in a desktop environment and exposes only a .NET API.
AutoCAD Map 3D stores some resource information directly in the DWG file, while MapGuide uses an external repository. This is explained in more detail in Resources. The MapGuide repository is structured like a file system, with a hierarchy of folders. To ensure as much consistency between the products as possible, AutoCAD Map 3D uses a similar structure for its internal repository.
Some methods in the Geospatial Platform API are not valid in AutoCAD Map 3D, and will throw an exception if called. Generally these will be methods that do not have corresponding functionality in the AutoCAD Map 3D environment. For example, AutoCAD Map 3D does not have the concept of permissions on resources so any methods dealing with permissions are invalid. These are identified in the API Reference.
All map data in a MapGuide application is written and read through FDO connections. This means that updates occur immediately. AutoCAD Map 3D works with data stored in the DWG file as well as FDO data. Depending on the method chosen, updates in a AutoCAD Map 3D application may be cached and not written directly to the feature source.
Differences in operation between AutoCAD Map 3D and MapGuide mean that in some cases the Geospatial Platform API has a different implementation in the products. AutoCAD Map 3D includes a set of classes that extend the API. For example, the Geospatial Platform API has an MgLayerBase class. AutoCAD Map 3D extends this in the AcMapLayer class.