Compute Concave Polygon

Function Description

Concave Polygon means that when one of the sides of a polygon is infinitely extended to two directions to form a straight line, the other sides are not on the same side of the straight line, then the polygon is called Concave Polygon, and at least one of its interior angles is a dominant angle (that is, an angle greater than 180 ° and less than 360 ° of the circumference angle). Concave Polygon as shown in Figure 1 below, where ∠ ABC is the dominant angle; extend the AB line, and the other sides of the polygon are not on the same side of the AB extension line. Corresponding to Concave Polygon, another type of polygon is convex polygon, which means that when any one of the sides of a polygon is infinitely extended to two directions to form a straight line, the other sides are on the same side of the straight line, then the polygon is called convex polygon, and all its interior angles are Is no more than180 degrees. The line segment between any two vertices is inside or on the edge of the polygon, as shown in Figure 2.

When a polygon is needed to represent the point coverage of a certain area, it is usually represented by Concave Polygon, because convex polygons will contain more blank surplus areas, and Concave Polygon can better express the real point distribution than convex polygons.
Supports the calculation of the Concave Polygon for all point objects in a specified point set by specifying the minimum interior angle of the point set or Point Dataset and Concave Polygon. The minimum internal angle of the Concave Polygon affects the area of the generated Concave Polygon. Generally, the smaller the angle is, the smaller the area is. In order to obtain the minimum Concave Polygon containing the specified point object, it is not better to set the angle as small as possible, because the smaller the angle, the sharper the polygon, which can not optimally reflect the real point object distribution.

Applicable Dataset: Point Dataset.

Function entrance

Data tab-> Data Processing-> Vector-> Compute Concave Polygon.
Toolbox, Data Processing, Vector, Compute Concave Polygon.

Parameter Description

Source Data: Select Datasource and Point Dataset to Compute Concave Polygon.
Angle: The minimum angle to generate the interior angle of the Concave Polygon. The settable angle Valid Range is between 0 ° and 180 ° (excluding 0 ° and 180 °), and the program default is 45 °.
Result Data: The Create Dataset checkbox is checked by default to generate a new Region Dataset. The default name of the Create Dataset is "result _ computeConcave Polugon" ".

Application example

Case description

A logistics company divides the delivery area according to the parcel delivery point, and chooses the parcel delivery Point DatasetCompute Concave Polygon.

Data description

Point Dataset of the parcel delivery point.

Main operation steps

Click the Compute Concave Polygon button in the Data tab-> Data Processing group-> Vector category.
Select the Datasource and Dataset to be Compute Concave Polygon in the pop-up Compute Concave Polygon window.
Set the angle to 45 °, and then click the Execute button to get the result as shown in the following figure:

Figure: Compute Concave Polygon result