area_center_points_xldarea_center_points_xldAreaCenterPointsXldAreaCenterPointsXld (Operator)

Name

area_center_points_xldarea_center_points_xldAreaCenterPointsXldAreaCenterPointsXld — Area and center of gravity (centroid) of contours and polygons treated as point clouds.

Signature

Description

area_center_points_xldarea_center_points_xldAreaCenterPointsXldAreaCenterPointsXldAreaCenterPointsXld calculates the area and center of gravity (centroid) of the point clouds given by contours or polygons XLDXLDXLDXLDXLD (i.e., the order of the points in the contour or polygon is not taken into account). The area corresponds to the number of points in the point cloud. The centroid is given by the arithmetic mean of all points. If the contour or polygon is closed (end point = start point), the end point of the contour or polygon is not taken into account to avoid that it receives twice the weight of the other points.

area_center_points_xldarea_center_points_xldAreaCenterPointsXldAreaCenterPointsXldAreaCenterPointsXld should be used if the contour XLDXLDXLDXLDXLD intersects itself or if it is not possible to close the contour using a line from end to start point without self-intersection, because in this case area_center_xldarea_center_xldAreaCenterXldAreaCenterXldAreaCenterXld does not produce useful results. To test whether the contours or polygons intersect themselves, test_self_intersection_xldtest_self_intersection_xldTestSelfIntersectionXldTestSelfIntersectionXldTestSelfIntersectionXld can be used.

If more than one contour or polygon is passed, the results are stored in tuples in the same order as the respective contours or polygons in XLDXLDXLDXLDXLD.

Attention

Even if the contour or polygon XLDXLDXLDXLDXLD is not intersecting itself, the result of area_center_points_xldarea_center_points_xldAreaCenterPointsXldAreaCenterPointsXldAreaCenterPointsXld significantly differs from the result of area_center_xldarea_center_xldAreaCenterXldAreaCenterXldAreaCenterXld as it is calculated from the point cloud and not from the enclosed region.

Execution Information

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Automatically parallelized on tuple level.

Parameters

Complexity

Let n be the number of points of the contour or polygon. Then the run time is O(n).

Result

area_center_points_xldarea_center_points_xldAreaCenterPointsXldAreaCenterPointsXldAreaCenterPointsXld returns 2 (H_MSG_TRUE) if the input is not empty. If the input is empty the behavior can be set via set_system(::'no_object_result',<Result>:)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>). If necessary, an exception is raised.

Possible Predecessors

gen_contours_skeleton_xldgen_contours_skeleton_xldGenContoursSkeletonXldGenContoursSkeletonXldGenContoursSkeletonXld, smooth_contours_xldsmooth_contours_xldSmoothContoursXldSmoothContoursXldSmoothContoursXld, gen_polygons_xldgen_polygons_xldGenPolygonsXldGenPolygonsXldGenPolygonsXld

Alternatives

area_center_xldarea_center_xldAreaCenterXldAreaCenterXldAreaCenterXld

See also

moments_points_xldmoments_points_xldMomentsPointsXldMomentsPointsXldMomentsPointsXld, moments_any_points_xldmoments_any_points_xldMomentsAnyPointsXldMomentsAnyPointsXldMomentsAnyPointsXld, area_centerarea_centerAreaCenterAreaCenterAreaCenter, moments_region_2ndmoments_region_2ndMomentsRegion2ndMomentsRegion2ndMomentsRegion2nd

Module

Foundation