Buffer
Function Overview
The Buffer tool creates polygon buffer areas at a specified distance around input features. It supports point, line, and polygon geometries, and provides multiple buffer styles and parameter options for different spatial analysis scenarios.
Use Cases
Urban Planning And Management
- Determine service areas for public facilities, such as schools and hospitals.
- Evaluate safe distances between buildings and features such as roads or rivers.
- Plan influence areas for urban green spaces and parks.
Environmental Protection
- Delineate water source protection zones.
- Evaluate the impact area of pollution sources on the surrounding environment.
- Determine protection ranges for ecologically sensitive areas.
Transportation Planning
- Analyze the impact range of traffic noise.
- Evaluate the surrounding impact of road widening or new road construction.
- Plan coverage areas for public transit stops.
Public Safety
- Delineate security zones for important facilities, such as government agencies or military bases.
- Analyze the impact range of crime hotspots.
- Plan coverage areas for emergency response services.
Parameters
Basic Settings (Required)
| Parameter | Description | Data type |
|---|---|---|
| Input vector file | Features to buffer. | Point, line, polygon |
| Buffer method | Method used to build the buffer. Use the planar method for projected coordinate systems and the geodesic method for geographic coordinate systems. | |
| Buffer distance | Distance from the input features to be buffered, in meters. | |
| Approximate circular segments | Number of line segments used to approximate circular buffer boundaries. A larger value produces smoother buffer edges closer to a circle. The default value is 8. | |
| End cap style | Controls the shape of buffers at feature endpoints. Options include round, flat, and square. Round creates a semicircular smooth end, flat truncates the end at a right angle, and square extends the buffer beyond the original line endpoint as a square. Point features support only round and square; line features support all options; polygon features do not support this option. | |
| Join style | Controls the shape of buffers at feature corners. Options include round, mitre, and bevel. Round creates an arc transition at line corners, mitre creates a sharp extended corner, and bevel truncates the corner with a flat connection. Join style supports only line and polygon features, not point features. | |
| Mitre limit | Used with the mitre join style to control the spike extension length at sharp corners and prevent excessively long abnormal geometries. The default value is 8. | |
| Dissolve | If selected, buffer areas are dissolved. Otherwise, each feature's buffer remains an independent feature. | |
| Single-sided buffer | If selected, only one side of the feature is buffered. The default side is left. | |
| 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 Selection
- Use the planar method with projected coordinate systems and the geodesic method with geographic coordinate systems. Do not mix them.
- Linear units should be consistent with the buffer distance unit.
Data Quality Checks
- Check feature geometry validity to avoid self-intersections, empty geometries, and similar issues.
- Confirm that the feature type, such as point, line, or polygon, matches the intended analysis.
- Handle abnormal values, such as extremely short line segments or very small polygon features.
Geometry Processing Options
- Choose the join style, such as round, mitre, or bevel, according to the analysis requirement.
- Set a reasonable mitre limit to control sharp-corner extensions.
Operating Steps
Step 1: Start The Tool
Open the Geoprocessing Toolbox, go to Analysis Tools > Neighborhood Analysis, and double-click Buffer to open the tool pane.
Step 2: Set Parameters
Select the input features, choose the appropriate buffer method based on the coordinate system of the features, and set the buffer distance, end cap style, join style, and dissolve option.
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.