Union Features
Function Overview
The Union Features tool calculates the geometric union of input features and generates a new dataset containing the geometry and attributes of all input features. It performs a spatial union operation, preserving all parts of the input features, including overlapping and non-overlapping areas. It is a core tool for spatial data integration and comprehensive analysis.
Use Cases
Administrative Boundary Merging And Regional Planning
- Merge boundaries from multiple counties to generate the complete coverage of a larger region, such as a state or province.
- In urban planning, merge different functional zones, such as residential, commercial, and industrial zones, to analyze overall land use.
Land Use And Land Cover (LULC) Analysis
- Merge land use data from different years to analyze land use change trends.
- Combine multiple land cover types, such as forest, farmland, and water, to generate an integrated map.
Ecological Protected Areas And Biodiversity Research
- Merge boundaries of multiple protected areas, such as national parks and wildlife reserves, to form a complete conservation network.
- Analyze overlaps among different ecological areas, such as the overlap between wetlands and forests.
Disaster Risk Assessment
- Merge flood risk zones, seismic belts, and landslide areas to generate an integrated disaster risk map.
- Analyze areas threatened by multiple hazards at the same time, such as high-risk zones for both floods and earthquakes.
Parameters
Basic Settings (Required)
| Parameter | Description | Data type |
|---|---|---|
| Input vector file | First feature layer for the union operation. | Point, line, polygon |
| Input vector file | Second feature layer for the union operation. | Point, line, polygon |
| Output path | Storage path for the output result. | Folder path |
| Output file name | File name of the output vector file. | Text, without extension |
Advanced Settings (Optional)
| Parameter | Description |
|---|---|
| File format | Output file format. The default is GPKG VectorData (.gpv). PostGIS VectorData (.pgv), ESRI Shapefile (.shp), Keyhole Markup Language (KML) (.kml), GeoJSON (.geojson), AutoCAD DXF (.dxf), and other formats are also supported. |
| Output specified fields | When enabled, output fields can be configured manually. When disabled, the original field structure is retained. |
| Reproject | When enabled, the spatial reference of the output file can be set. Otherwise, the coordinate system of the input features is used. |
Notes
Coordinate System Consistency
- All input layers must use the same coordinate system. A projected coordinate system is recommended.
- If coordinate systems differ, use a projection tool to convert them to a common coordinate system first.
Geometry Validity Checks
- Use a geometry check tool to repair self-intersections, empty geometries, duplicate vertices, and similar issues to avoid failures or abnormal results.
Consistent Input Geometry Types
- All input feature classes must have the same geometry type, such as all polygons, all lines, or all points.
Operating Steps
Step 1: Start The Tool
Open the Geoprocessing Toolbox, go to Analysis Tools > Overlay Analysis, and double-click Union Features to open the tool pane.
Step 2: Set Parameters
Enter the features for the union operation, output path, and output file name. All parameters are required.
Step 3: Run And Monitor The Task
Click Run to start processing. You can view progress, run time, and completion status in the task list.
If the run fails, the tool provides an error message. Use the Edit button in the lower-right corner to return to the tool pane and adjust the parameters.