Arc GIS Overlay Functions
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This document discusses six types of overlay operations in GIS: intersection, union, erase, identity, symmetrical difference, and update. It provides a brief definition of each type of overlay, describing how features from multiple layers are combined or modified spatially and in their attributes.
Arc GIS Overlay Functions
- 1. Overlay! By Ehsan Hamzei 810392121
- 2. Type of Overlay • Intersection • Union • Erase • Identity • Symmetrical Difference • Update
- 3. Intersect • Computes a geometric intersection of the input features. Features or portions of features which overlap in all layers and/or feature classes will be written to the output feature class.
- 4. Union • Computes a geometric union of the input features. All features and their attributes will be written to the output feature class.
- 5. Erase • Creates a feature class by overlaying the Input Features with the polygons of the Erase Features. Only those portions of the input features falling outside the erase features outside boundaries are copied to the output feature class.
- 6. Identity • Computes a geometric intersection of the input features and identity features. The input features or portions thereof that overlap identity features will get the attributes of those identity features.
- 7. Symmetrical Difference • Features or portions of features in the input and update features that do not overlap will be written to the output feature class.
- 8. Update • Computes a geometric intersection of the Input Features and Update Features. The attributes and geometry of the input features are updated by the update features in the output feature class.
- 9. References • ESRI Arc GIS Help…
- 10. Thanks