SuperMap currently provides seven Overlay Analysis operators. The following are introduced separately:
6.Intersection negation (Symmetry difference）
Crop
Clipping is the operation of extracting part of the feature set from the Clip Dataset using the Clip Dataset. The set of polygons in the Clip Dataset defines the clipping area. All features in the Clip Dataset that fall outside these polygonal areas will be removed, while features that fall inside the polygonal areas will be output to the Result Dataset.
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| Figure: Schematic diagram of clipping operation |
The attribute table of the Output Result of the clipping operation comes from the attribute table of the Clip Dataset, and its Table Structure is the same as that of the Clip Dataset, except that the area, perimeter, length, etc. Need Recalculate. The remaining attribute values are retained by Clip DatasetA. Automatically Add all fields in DatasetA, as shown in the following figure.
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Union (Merge)
A merge is an operation that finds the union of two Datasets. Aft that merge operation, the polygons of the two Region Dataset are split at the intersection, the Topology is reconstructed, and the geometry and Attributes of the two Datasets are output to the Result Dataset.
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| Figure: Schematic diagram of consolidation |
The attribute table of the Output Result of the consolidation operation comes from the two input Dataset Properties tables. During the consolidation operation, the user can select the Property Field to be reserved in the attribute tables of A and B according to his own needs.
At present, the Overlay Analysis ResultField is "Field _ 1" and "Field Name _ 2", as shown in the following figure.
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Erase
Erase is the operation that erases the part of the polygon that is coincident with the polygon in the Erase Data set. The set of polygons in the Erase Data set defines the erase areas. Features in the Erase Data set that fall within these polygon areas will be removed, while features that fall outside the polygon areas will be output to the Result Dataset. The erase operation is the same as the trim operation, except for the content retained in the Source Dataset.
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| Figure: Schematic diagram of erase operation |
The attribute table of the Output Result of the Erase operation is from the attribute table of the Erased Data set, and its type is the same as the Erased Dataset Type. As shown in the following figure, all Non-system Fields in the DatasetA attribute table are automatically added:.
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Ask for intersection
The intersection operation is the operation of finding the intersection of two Datasets. The feature object of the Dataset to be intersected is split at the intersection with the polygon in the intersection Dataset (except for the point object).
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| Figure: Schematic diagram of intersection operation |
The Result Dataset property list for intersection includes not only its own Property Field, but also the Dataset to be intersected and all the Property Fields of the intersected Dataset. Users can select the fields they need to keep from the and B Dataset Properties tables according to their own needs. As shown in the following figure:
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Identify (Same)
Identify (Same) Result Layer Range: Same as the Source Dataset layer, but contains the geometry and attribute data from the Overlay Dataset layer. The Identify (Same) operation is an operation in which the Source Dataset and the Overlay Dataset are first intersected, and then the intersection result is merged with the Source Dataset. If the first Dataset is a point set, the newly generated Dataset retains the All Objects of the first Dataset; If the first Dataset is a Line Dataset, the newly generated Dataset retains the All Objects of the first Dataset, but breaks the objects that intersect with the second Dataset at the intersection; If the first Dataset is a Region Dataset, the Result Dataset retains all polygons within the control boundary of the Source Dataset, and objects that intersect the second Dataset are split into multiple objects where they intersect. (Note: When Overlay Data has overlapping faces, multiple objects are generated as a result).
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| Figure: Schematic diagram of the same operation |
The Property sheet fields of Output Result of the same operation, except System Field:, are all from the Property Fields of the two Input Data: sets. Select Field from the Property Fields of the Source Dataset and Overlay Dataset. As shown in the following figure:
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Intersection Difference (Symmetric Difference)
The symmetric difference operation is the exclusive or of two Datasets. The result of the operation is that for each face object, the part that intersects the Geometry in the other Dataset is removed, and the remaining part is retained.
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| Figure: Schematic diagram of symmetrical difference operation |
The property table of the Output Result of the symmetric difference operation contains two non-system Property Fields of the Input Data Set, as shown in the following figure:
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Update
The update operation is to replace the part coinciding with the Updated Dataset with the Update Data set, which is a process of first erasing and then pasting. The geometry and Attributes of the Update Dataset are preserved in the Result Dataset.
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| Figure: Schematic diagram of update operation |
The attribute table of the update operation Output Result is shown in the following figure. The attribute value of the overlapping part of A and BDatasetGeometry is updated to the attribute value of B.
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