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Vector overlay is an operation (or class of operations) in a geographic information system (GIS) for integrating two or more vector spatial data sets. Terms such as polygon overlay, map overlay, and topological overlay are often used synonymously, although they are not identical in the range of operations they include.
In computer graphics, line clipping is the process of removing lines or portions of lines outside an area of interest (a viewport or view volume). Typically, any part of a line which is outside of the viewing area is removed. There are two common algorithms for line clipping: Cohen–Sutherland and Liang–Barsky.
Modern implementations for Boolean operations on polygons tend to use plane sweep algorithms (or Sweep line algorithms). A list of papers using plane sweep algorithms for Boolean operations on polygons can be found in References below. Boolean operations on convex polygons and monotone polygons of the same direction may be performed in linear ...
Clipping is defined as the interaction of subject and clip polygons. While clipping usually involves finding the intersections (regions of overlap) of subject and clip polygons, clipping algorithms can also be applied with other boolean clipping operations: difference, where the clipping polygons remove overlapping regions from the subject; union, where clipping returns the regions covered by ...
Polygon: a region also includes an infinite number of points, so the vector model represents its boundary as a closed line (called a ring in OGC-SFA), allowing the software to interpolate the interior. GIS software distinguishes the interior and the exterior by requiring that the line be ordered counter-clockwise, so the interior is always on ...
Cyrus–Beck is a general algorithm and can be used with a convex polygon clipping window, unlike Cohen-Sutherland, which can be used only on a rectangular clipping area. Here the parametric equation of a line in the view plane is p ( t ) = t p 1 + ( 1 − t ) p 0 {\displaystyle \mathbf {p} (t)=t\mathbf {p} _{1}+(1-t)\mathbf {p} _{0}} where 0 ...
In computer graphics, the Cohen–Sutherland algorithm is an algorithm used for line clipping.The algorithm divides a two-dimensional space into 9 regions and then efficiently determines the lines and portions of lines that are visible in the central region of interest (the viewport).
Sliver polygons are typically created when polygons are automatically generated from lines that should be coincident (e.g., an international boundary following a river de jure, or two adjacent counties) but are not, due to the natural discrepancies that arise from manual or automated digitization. This can occur when a single layer is digitized ...