[data capture] The geometric center of a feature. For line, polygon, or three-dimensional features, it is the center of mass (or center of gravity) and may fall inside the feature, as shown below for a triangle, or outside the feature, as shown below for a complex line. For multipoints, polylines, or polygons with multiple parts, it is computed using the weighted mean center of all feature parts. The weight for a point feature is 1, for a line feature is its length, and for polygon features is its area.