Feature Description
Layer intersection is an analysis function that performs an intersection operation on two datasets. For a detailed introduction to the intersection tool, please refer to the Overlay Analysis Tool.
- The source dataset type can be point, line, or region dataset. The overlay dataset type can be line or region dataset. The overlay dataset supports the line type only when the source dataset is a line.
- The result dataset retains the overlapping portion of the original two datasets. When intersecting line with line, a point dataset can be obtained, and the output type must be set to point in this case.
Function Entry
- Spatial Analysis tab -> Vector Analysis -> Overlay Analysis -> Intersect.
- Toolbox -> Vector Analysis -> Overlay Analysis -> Intersect.
Parameter Description
- Source Data: Select the datasource containing the datasets to be intersected and the datasets to be intersected. Multiple datasets can be input for intersection analysis.
- Overlay Data: Select the dataset to be intersected with the source dataset and its containing datasource.
- Tolerances: A default tolerance value is automatically provided based on the datasets involved in the analysis.
After the overlay operation, if the distance between two nodes is less than this value, the two nodes will be merged. The default value of this tolerance is the default fuzzy value of the clipped dataset. This value can be set in the fuzzy field under tolerances on the vector dataset tab of the dataset properties dialog box.
If the fuzzy value is not set in the dataset properties, the default tolerance here is related to the coordinate system of the dataset. For details, please refer to Tolerance Description.
- Result Data: Select the datasource to store the result dataset and specify the name of the result dataset.
- Reserved Fields: Select fields from the source dataset and the overlay dataset as the fields of the result dataset.
- Output Result Type: The output result type of the intersection analysis is consistent with the source dataset type by default. When both the source data and the overlay data are lines, the output result should be set to point type; otherwise, the execution will fail. For example, to obtain the intersection points of road lines and river lines as bridge data, the output result type should be set to point.
For example: Taking Figure 1 below as an example, the field ridge is located at the boundary between two patches with classification codes 0321 and 0110. To calculate the net area of the patches, the patch area is first calculated, and the area of the linear field ridges needs to be deducted. Since the linear field ridges are on the edge of the patches, only half of their area is deducted. Through the intersection operation, if "Single Object" is checked, the returned result ridge belongs to only one of the patches, as shown in Figure 2. If it is not checked, the returned result retains both line objects, as shown in Figure 3. Then, by specifying the patch ID and deducting the polyline area within the corresponding patch, the net area result can be obtained.
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