Feature Description
This method provides overlay analysis for multiple layers or datasets. Multi-layer overlay analysis can address the need for users to perform overlay analysis on multiple datasets simultaneously, such as intersecting data from multiple years. The original method for overlaying two datasets can achieve similar results through two overlay analyses, but the operation is too cumbersome.
Distributed multi-layer overlay analysis offers two functions: ordinary 【Multi-Layer Overlay Analysis】 and 【DSF Multi-Layer Overlay Analysis】. The difference lies in the input data sources:
【Multi-Layer Overlay Analysis】 can input datasets read from various vector data sources, such as SHP, PostGIS, Oracle, etc.;
【DSF Multi-Layer Overlay Analysis】 can only input datasets read from SuperMap DSF data sources. DSF is a vector data storage method optimized for distributed computing, which can significantly improve computational performance for large data volumes. This method is recommended for vector overlays at the ten-million level and above.
The distributed multi-layer overlay analysis supports the following types of operations: intersection and union.
Parameter description
【Multi-Layer Overlay Analysis】 and 【DSF Multi-Layer Overlay Analysis】 have the same parameters. The difference lies in the parameter types for join data and target dataset. 【Multi-Layer Overlay Analysis】 requires input of FeatureRDD type, while 【DSF Multi-Layer Overlay Analysis】 requires input of DSFFeatureRDD type:
| Parameter Name | Default Value | Parameter Interpretation | Parameter Type |
|---|---|---|---|
| Overlay analysis dataset | An array of polygon datasets for overlay analysis, requiring at least 2 datasets and supporting up to 10 datasets | FeatureRDD/DSFFeatureRDD | |
| Overlay analysis type of operation | Supports intersection and union operations. | JavaSpatialOperatorType | |
| Field attribute return form | The form in which field attributes are returned in the overlay analysis result. Users can choose to return only Feature ID, only property field values, or both (ALL). | JavaOverlayOutputAttributeType | |
| Fuzzy (Optional) |
0.0 | Fuzzy. The default value is 0.0. When the tolerance is less than 1.0e-10, if the dataset's coordinate system is a geographic coordinate system, a fuzzy of 1.0e-8 will be used. When the coordinate system is empty or a projected coordinate system, a fuzzy of 1.0e-3 will be used. | Double |
Notes
- Function Change: Starting from SuperMap 2025 version, overlay analysis of data with different coordinate systems is supported. The result data of multi-layer overlay analysis is consistent with the coordinate system of the first layer.