Function Description
Aggregate Polygons merges polygon features within a specified distance into a new polygon feature, resulting in an aggregated polygon feature dataset.
Application Scenarios
A common application scenario is determining the aggregation level of rural settlements, which typically requires indicators like contiguity. Contiguity refers to aggregating plots or buildings within a certain range into a single patch, such as clustering construction land plots with a 100-meter aggregation distance—each plot is buffered by 100 meters and aggregated if within range.
Different aggregation distances produce varying results, as shown below:
To exclude isolated small fragments from the data, set the minimum area in parameters, as shown below:
Sometimes, holes (gaps) may appear in the results; these can be eliminated by setting the hole minimum area in parameters, as shown below:
Function Entry
- Data选项卡->Data Processing->Vector->Aggregate Polygons。
- Toolbox->Data Processing->Vector->Aggregate Polygons。
Parameter description
- Source Dataset：Set the dataset and data source to be processed. The dataset must be a polygon dataset.
- Aggregation Distance：Sets the distance between polygon feature boundaries that must be satisfied for aggregation to occur. Values must be greater than 0.
- Unit：Sets the unit for the aggregation distance. In planar coordinate systems and projected coordinate systems, the default is meters; in geographic coordinate systems, it defaults to degrees.
- Minimum Area：Sets the minimum area for independent small fragments in the aggregation result; fragments smaller than this will be removed. The area unit matches the aggregation distance unit—e.g., if meters are selected, the area is in square meters. Default is 0, preserving all polygons.
- Hole Minimum Area：Sets the minimum area for holes inside aggregated polygons; holes smaller than this will be filled. The area unit matches the aggregation distance unit—e.g., if meters are selected, the area is in square meters. Default is 0, preserving all holes.
- Aggregation Field：Only features with the same aggregation field value will be aggregated. For example, when aggregating building polygons, nearby water polygons should not merge. Supported field types include Boolean, Integer, Long, Date, and Timestamp.
- Result Data：Set the result datasource and dataset name.
Related Topics