Analytical operations such as buffers and overlays can be performed on any feature instances of a Map Manager layer. These operations produce new features instances in a new layer. The features can be reviewed and reported on like any other feature.

A buffer is a feature instance created at a specified distance around another feature. Buffers can be generated for all feature instances, only those within a specified spatial extent, or those that meet certain criteria.

An overlay is the combination of two layers to create a new feature instance. To combine two layers in an overlay, right-click on a layer and select Overlay. The Topology Analysis dialog opens with the selected layer in the “Layers to be overlaid” list box. If two layers are selected in the Map Manager, then both of those layers will populate the layers list. A new layer in the Map Manager will be created with the properties from both of the layers that were overlaid. This layer consists of MicroStation elements that can be edited and reported on using OpenCities Map tools.

Buffer operations are available in 2D and 3D models.

Overlay operations are only available in 2D models.