Identify (Same)

Function Description

The identify (same) operation performs an intersection between the source dataset and overlay dataset. For details, see overlay analysis introduction.

Feature Entry

  • Spatial Analysis Tab -> Vector Analysis -> Overlay Analysis -> Identity.
  • Toolbox -> Vector Analysis -> Overlay Analysis -> Identity.

Parameter Description

  • Source Data: Select the source dataset and its datasource for the identity operation.
  • Overlay Data: Select the dataset and its datasource to perform identity operation with the source dataset.
  • Keep Overlaps of Source Data: When both polygon datasets have complex topology (e.g., both source and overlay data contain overlapping layers), checking this parameter will output results based on the source data's overlap relationships. For example, if both datasets have two overlapping layers: unchecking produces four overlapping layers in output, checking maintains the source's two layers to ensure correctness.
  • Tolerances: Default tolerance values are automatically provided based on participating datasets.

    After overlay operation, if the distance between two nodes is smaller than this value, they will be merged. The default value is the fuzzy tolerance of the clipped dataset, which can be set in the Fuzzy field under Vector Dataset Tab > Tolerances in Dataset Properties dialog.

    If fuzzy tolerance isn't set in Dataset Properties, the default tolerance relates to dataset's coordinate system. See Tolerance Description.

  • Result Data: Select the datasource to store result dataset and specify its name.
  • Field Settings: Select fields from source dataset and overlay dataset as output fields.
  • Keep All Source Data Fields: Check to retain all source data fields. If source and overlay data have identical field names, source fields will be named "FieldName_1" and overlay fields "FieldName_2".
  • Keep All Overlay Data Fields: Check to retain all overlay data fields. Naming convention for duplicate fields follows the same rule as above.
Notes:

Ensure datasets have consistent projections before performing overlay analysis, otherwise the operation may fail.

Related Topics

About Overlay Analysis

Overlay Analysis Tools