Journal of Geo-information Science >
Simulated Expression Method of Spatial Relationship of Natural Language of Point, Line and Object
Received date: 2017-06-29
Request revised date: 2017-11-23
Online published: 2018-03-02
Supported by
National Natural Science Foundation of China, No.41571382, 61472191
Major Projects of Natural Science Research in Colleges and Universities of Jiangsu, No.15KJA420001
Copyright
Descriptions of natural language contain abundant geographical spatial information including geographical objects, spatial relations, attribute information and so on. Among them, the understanding of spatial relations tend to play a decisive role in understanding the whole description statement. However, the uncertainty, ambiguity,flexibility and other features of descriptions of natural language make it difficult for computer to understand and process natural language. Taking the natural language as a breakthrough point, we explore description of spatial relationship in natural language and visualization under fuzzy semantics, and realizes the goal of "text-to-figure" transformation. We focus on establishing the mapping relationship between the qualitative description language and quantitative graphic language. According to different levels of "vagueness", descriptions can be divided into three categories, namely completely fuzzy description, interval fuzzy description and quantitative fuzzy description, so as to study the natural language description based on different categories and levels. Furthermore, we put forward two methods of visualization expression: random parameter method and buffer method, which realize the visualization of spatial relations descriptions of natural language. In the example of Xianlin campus of Nanjing Normal University, the system adopts a three-tiered architecture containing user layer, service layer and data layer. We also design and develop the analogous expression system of spatial relations of natural language, which realizes the "text-to-figure" conversion between fuzzy natural language description and point-line features, and verifies the validity of the method proposed in this paper. Most importantly, this system contributes a lot to recognition, reasoning, calculation, formal expression and visualization expression of geographical spatial information.
Key words: natural language; spatial relation; simulated expression
TANG Tianqi , CAO Qing , ZHANG Ling , LONG Yi . Simulated Expression Method of Spatial Relationship of Natural Language of Point, Line and Object[J]. Journal of Geo-information Science, 2018 , 20(2) : 139 -146 . DOI: 10.12082/dqxxkx.2018.170296
Tab. 1 Comparison of the description of different spatial granularities表1 不同空间粒度描述对比 |
完全模糊描述 | 区间模糊描述 | 定量模糊描述 | ||
---|---|---|---|---|
模糊性程度 | 低 | 一般 | 丰富 | |
描述特点 | 具有模糊含义词汇 | 模糊含义词汇 + 定量参数范围 | 模糊含义词汇 + 定量参数 | |
示例 | 距离关系 | 33幢离行知楼较远 | 33幢离行知楼300~400 m远 | 33幢离行知楼大概320 m,步行约6 min |
方向关系 | 34幢在学行楼西北部 | 34幢位于学行楼北偏西60~70°之间 | 34幢在学行楼北偏西65°左右 | |
方向关系 +距离关系 | 行远楼在体育场东北方向不远处 | 行远楼位于体育场东北方向,100~200 m处 | 行远楼在体育场北偏东30°方向,200 m左右,步行大约2 min |
Fig. 1 Unequal distance division图1 非等距离划分 |
Fig. 2 Visualization expression of random parameter and buffer methods图2 缓冲区法与随机参数法可视化表达 |
Tab. 2 The examples of distance relation descriptions表2 距离关系描述语句示例 |
Fig. 3 Directional partitioning based on taper图3 基于锥形的方向划分 |
Fig. 4 The eight-directional relationship model图4 八方向关系模型 |
Fig. 5 Cartographic visualization of spatial direction图5 空间方向的地图可视化 |
Fig. 6 Implementation process of the prototype system图6 原型系统实现流程 |
Fig. 7 Semantic parsing implementation图7 语义解析实现 |
Fig. 8 Comparison between simulated results and electronic maps图8 模拟表达结果与电子地图对比(1:15 000) |
Tab. 3 Evaluation of experimental results表3 实验结果评价 |
缓冲区法表达结果 | 随机参数法表达结果 | ||
---|---|---|---|
空间 关系 表达 | 距离关系 | 有差异 | 有差异 |
方向关系 | 基本一致 | 基本一致 | |
拓扑关系 | 一致 | 一致 | |
表达 效果 | 特点 | 不同缓冲区范围能清楚的反应其描述对应的模糊等级 | 所有线要素宽度一致,区别较小 |
缺点 | 实际生活中学林路为一条“弯曲”的道路,但是2种方法未表现出来 |
The authors have declared that no competing interests exist.
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