摘要
时间地图是一种以时间为量测单位,替代传统道路专题地图中空间距离的专题地图。假设可以使用空间方向和时间两个属性来构建时间地图的两个维度,并基于旅行者的运动轨迹,采用地图学制图原理和数学分析方法,给出了传统道路专题地图中的道路变换到时间地图中的数学变换模型,分析了变换模型的特性。研究了时间地图的变形内涵、测度方法,给出了对应的变形测度计算公式,解释了其相应的地理学意义。最后以江苏省道路为实例对象,将江苏省道路专题地图中的道路变换到时间地图中,分析了时空地图的结构和表达的主要影响因素。研究表明:基于旅行者的运动轨迹,可以将传统道路专题地图中的道路变换到时间地图中。旅行者出发点的位置和出发点周围的道路等级、运动速度和运动方向是影响时间地图结构和表达的重要因素。时间地图和传统地图之间具有相似性。余弦相似度指数能够测度时间地图和传统地图的相似性,地图相似性指数既表征了时间地图和传统地图相互关联特性,也反映了地图认知的难易程度,而且局部相似度指数也反映了时间地图在局部区域受到了外力的作用程度。提出的时间地图变换模型拓宽了变形地图的变换方法,将对交通可达性等问题的研究产生影响。
In order to implement a transformation from a traditional thematic map to a time map, this paper investigates a time map transformation model. Two assumptions are made to build a transformation model that transforms a road thematic map to a time map based on a trajectory of traveler's motion. One is that the time map can be described in a two-dimensional spatial direction and temporal distance, and the other is that direction of the travelers' motion accords with the real spatial direction. This paper builds a transformation model based on these assumptions by means of cartography and mathematical analysis. First, the differential expressions from road motion trajectory to time map are provided. Next, the characteristics of the transformation model are analyzed. The definition of time map distortion, a depiction of the method used to measure the distortion and an explanation of the geographic significance of the distortion are also provided, as well as the calculation formula used for the distortion measurement. Finally, this paper transforms the highway thematic map of Jiangsu province into a time map and analyzes the main influencing factors of the time map structures, representation and distortion. The results show that the traveler's motion trajectory can be transformed into a time map, and that there are many influencing factors, such as starting point, road level surrounding starting points, motion velocity and motion direction. Moreover, there are some similarities between the time map and the traditional thematic map that can be measured by cosine similarity. The similarity index between the time map and the traditional map shows both the correlation between them and the degree of difficulty of time map recognition. The local similarity index also reveals the influence of external forces on the local time map. The transformation model for the time map proposed in this paper could broaden the transformation theory of the cartogram and could also contribute to research on accessibility and its influencing factors.
出处
《地理研究》
CSSCI
CSCD
北大核心
2015年第6期1160-1172,共13页
Geographical Research
基金
国家自然科学基金项目(41271189
40971231
40971105)
江苏省高校优势学科建设工程项目
关键词
时间地图
运动轨迹
变换模型
曲线相似性
测度
time-space map
motion trajectory
map transformation
map similarity
measurement index
