Overlay Operations Tool

Another tool in Cartographica for promulgating attributes between layers is the Overlay Operations tool. This tool, and its associated operations, provide a way to manipulate both the attributes and the geometry of layers. Each overlay operation has a different geometric effect, and can also contribute attributes to the target layer(s).

Overlay Operations

OperationDescription
ClipTarget layer features are clipped to the features in the clipping layer.
EraseErase the target layer(s) with the erase layer. Portions in the target layers that match the erase layer are removed.
IntersectFeatures that overlap with all target layers are maintained. Note that this differs from clipping in that features are removed if they aren't present in all layers.
UnionFeatures in all Target Layers are kept. Overlapping features are combined.
DifferenceFeatures present in more than one layer are removed (possibly partially) to result in a layer that contains only the pieces of features that are only present in a single layer.
UpdateTarget layers are updated with geometry in the Update layer. Overlapping geometries will be replaced, and non-overlapping geometries (or parts thereof) will be retained.
IdentifyTarget layers are identified with the geometry in the Identify layer. Overlapping geometries will be updated to contain information from the Identify layer. Partially-overlapping geometries will be split into overlapping and non-overlapping parts.
Overlay Operations
Performing Overlay Operation
  1. Choose  Tools > Overlay Operations…
    The Overlay Operation window appears

    Overlay Operation Window
  2. Choose your operation from the Operation menu (see Overlay Operations table)
  3. Select your target layer(s) in  Target Layers
  4. If appropriate, drag an operation layer from the  Target Layers box to the operation box (which will be labeled according to the operation)
  5. Adjust your  Field Mappings as appropriate. Operation is identical to the Spatial Join Field Mapping section.
  6. Click  Perform

One the operation is complete, new layers corresponding to the Target layers should appear in the Layer Stack