About Invalid, Valid and Clean Polygons
About Invalid, Valid and Clean Polygons
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DOI：
10.1007/3-540-26772-7_1
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
P. V. Oosterom;W. Quak;T. Tijssen
中科院分区：
文献类型：
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作者：
P. V. Oosterom;W. Quak;T. Tijssen
空间模型通常基于2D和3D中的多边形。许多Geo-ICT产品支持基于OpenGIS“简单特征规范”的空间数据类型，如多边形。OpenGIS和ISO已同意统一其规范和标准。在本文中，我们将讨论这些标准中与多边形相关的相关方面，并比较几种实现方式。一个相当详尽的测试多边形（孔）已经开发。测试结果显示，在实现，这导致互操作性问题的显着差异。这些差异的一部分可以通过OpenGIS和ISO标准的不同解释（定义）来解释（没有相等的多边形定义）。这些差异的另一部分是由于典型的实现问题，例如处理公差的替代方法。基于这些经验，我们提出了一个明确的定义多边形，这使得多边形再次稳定的基础，它应该是在空间建模和分析。有效多边形定义明确，但由于它们仍可能在数据传输期间引起问题，因此还定义了（有效）干净多边形的概念。
Spatial models are often based on polygons both in 2D and 3D. Many Geo-ICT products support spatial data types, such as the polygon, based on the OpenGIS ‘simple Features Specification’. OpenGIS and ISO have agreed to harmonize their specifications and standards. In this paper we discuss the relevant aspects related to polygons in these standards and compare several implementations. A quite exhaustive set of test polygons (with holes) has been developed. The test results reveal significant differences in the implementations, which causes interoperability problems. Part of these differences can be explained by different interpretations (definitions) of the OpenGIS and ISO standards (do not have an equal polygon definition). Another part of these differences is due to typical implementation issues, such as alternative methods for handling tolerances. Based on these experiences we propose an unambiguous definition for polygons, which makes polygons again the stable foundation it is supposed to be in spatial modelling and analysis. Valid polygons are well defined, but as they may still cause problems during data transfer, also the concept of (valid) clean polygons is defined.