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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.
Simple tiles are generated by Möbius triangles with whole numbers p,q,r, while Schwarz triangles allow rational numbers p,q,r and allow star polygon faces, and have overlapping elements. 7 generator points
Here, a tiling is a covering of the plane by non-overlapping polygons or other shapes, and a tiling is aperiodic if it does not contain arbitrarily large periodic regions or patches. However, despite their lack of translational symmetry , Penrose tilings may have both reflection symmetry and fivefold rotational symmetry .
A Topological relation is a qualitative relationship between two shapes that does not depend on a measurable space (that is, coordinates). Common examples of such predicates include "A is completely inside B," "A overlaps B," "A is adjacent to B" (i.e., sharing a boundary but no interior), and "A is disjoint from B" (not touching at all).
There are 17 combinations of regular convex polygons that form 21 types of plane-vertex tilings. [6] [7] Polygons in these meet at a point with no gap or overlap. Listing by their vertex figures, one has 6 polygons, three have 5 polygons, seven have 4 polygons, and ten have 3 polygons. [8]
Star forms have either regular star polygon faces or vertex figures or both. This list includes these: all 75 nonprismatic uniform polyhedra; a few representatives of the infinite sets of prisms and antiprisms; one degenerate polyhedron, Skilling's figure with overlapping edges.
Some GIS software has tools for validating topological integrity rules (e.g. not allowing polygons to overlap or have gaps) on spaghetti data to prevent and/or correct topological errors. A hybrid topological data model has the option of storing topological relationship information as a separate layer built on top of a spaghetti data set.
There are three main types of computer environments for studying school geometry: supposers [vague], dynamic geometry environments (DGEs) and Logo-based programs. [2] Most are DGEs: software that allows the user to manipulate ("drag") the geometric object into different shapes or positions.