Feature Description
Used to calculate the minimum bounding geometry for individual or grouped objects, and output a polygon feature dataset (FeatureRDD). It supports calculating the following five types of minimum bounding geometry:
- Minimum width rectangle: The rectangle that encloses the input object with the smallest width.
- Minimum area rectangle: The rectangle that encloses the input object with the smallest area.
- Convex hull: The smallest convex polygon that encloses the input object.
- Minimum circumscribed circle: The smallest circular boundary that encloses the input object.
- Envelope rectangle: The smallest bounds parallel to the coordinate axes of the input object.
| source dataset | Minimum Width Rectangle | Minimum Area Rectangle | Convex Hull | Minimum Circumscribed Circle | Envelope Rectangle |
|---|---|---|---|---|---|
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Application Scenarios
Pollution source identification and analysis: Through the minimum bounding geometry tool, the minimum boundary range of pollution sources can be determined, which is crucial for identifying and analyzing the spatial distribution of pollution sources. For example, in the study of the spatiotemporal evolution of total nitrogen non-point source pollution load in a watershed, the minimum bounding geometry tool can be used to calculate the minimum bounding circle of the centroid of total nitrogen pollution load for each non-point source, thereby identifying the key recognition area for changes in total nitrogen pollution load of each pollution source.
Parameter description
| Parameter Name | parameter interpretation | parameter type |
|---|---|---|
| Input Feature Dataset | The point, line, or polygon feature dataset to be calculated. It is usually connected with the [Read Vector Data] tool to obtain input data. | FeatureRDD |
| group field | Specifies the grouping field. Geometries with the same field value will be grouped together and the minimum bounding geometry will be calculated. This parameter is required only when the group option is set to 'Group'. | String |
| Group Option | Specifies the grouping method for input data: - Each Feature: Each geometry is calculated independently for the minimum bounding geometry. - Group: Geometries are grouped based on the group field value, and one minimum bounding geometry is calculated for each group. The attribute value of the group field will be retained in the output polygon objects. - All: All geometries in the dataset are treated as one group, and only one minimum bounding geometry is output. |
String |
| Minimum Bounding Geometry Type | Specifies the required minimum bounding geometry type. It supports selecting minimum width rectangle, minimum area rectangle, convex hull, minimum circumscribed circle, and envelope rectangle. | String |
Output Result
| Parameter Name | parameter interpretation | parameter type |
|---|---|---|
| Minimum Bounding Geometric Dataset | A polygon feature dataset containing the calculated minimum bounding geometry. The calculation result of the distributed analysis tool is stored in memory and needs to be written to a database or local storage by connecting with the [Save Vector Data] tool. | FeatureRDD |
Precautions
Point dataset does not support creating minimum bounding boundaries for each feature. When inputting point data and the group option is set to 'Each Feature', an exception will occur during execution.
Special case handling for point dataset:
(1) When there is only one point or multiple coincident points in the point dataset or group, calculating the minimum circumscribed circle will output a circle with a diameter of 10^-6 times the unit length of the current dataset; calculating the minimum area rectangle, minimum width rectangle, convex hull, and envelope rectangle will generate a square with a side length of 10^-6 times the unit length of the current dataset.
(2) When there are only two point objects in the point dataset or group, for convex hull, minimum width rectangle, minimum area rectangle, and envelope rectangle (envelope rectangle only when the line feature is horizontal or vertical), a rectangle with a width equal to the length of the line segment connecting the two points divided by 100 is generated.
Special case handling for line dataset:
When there is only one straight line or multiple collinear lines in the line dataset or group, for convex hull, minimum width rectangle, minimum area rectangle, and envelope rectangle (envelope rectangle only when the line feature is horizontal or vertical), a rectangle with a width equal to the length of the line segment divided by 100 is generated.
When the input dataset is empty, an empty result dataset with 0 objects will be output.
When there are objects with empty Geometry in the input dataset, these objects will be ignored during calculation, and minimum bounding geometry will be created only for objects with non-empty Geometry.