An Algorithm for Locating Candidate Labeling Boxes Within a Polygon
An Algorithm for Locating Candidate Labeling Boxes Within a Polygon
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DOI：
10.1559/152304089783814034
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
J. Roessel
中科院分区：
文献类型：
--
作者：
J. Roessel
基于矢量的地理信息系统通常需要在多边形内的合适位置进行注释，例如多边形编号或属性数据。传统方法通常计算多边形质心，测试质心是否包含或排除，并在质心落在多边形之外时选择一些替代点。这种方法有两个问题：(1) 文本可以以点为中心，但可能放置在视觉上尴尬的位置，(2) 部分文本可能落在多边形之外，并且可能与其他多边形边界或其他文本标签重叠。提出了一种绕过这两个问题的算法，通过计算多边形内的多个水平候选标记矩形（框），从中可以做出合适的选择，或者可以得出文本标签不适合多边形的结论。
Vector-based geographic information systems usually require annotation, such as a polygon number or attribute data, in a suitable location within a polygon. Traditional methods usually compute the polygon centroid, test the centroid for inclusion or exclusion, and select some alternative point when the centroid falls outside the polygon. Two problems are associated with this approach: (1) the text can be centered on the point, but may be placed in a visually awkward place, and (2) part of the text may fall outside the polygon and may overlap other polygon boundaries or other text labels. An algorithm is presented that circumvents both of these problems, by computing a number of horizontal candidate labeling rectangles (boxes) within a polygon from which a suitable selection can be made or from which one may conclude that the text label does not fit the polygon.