微地图辅助寻路的方向—距离模型构建与表达

DDM: A Direction-Distance Model for We-Map Assistance Wayfinding

  • 摘要: 针对现有微地图辅助用户寻路的算法或模型未充分考虑辅助寻路的其它要素(如方向、距离等),致使在寻路过程中缺失关键信息的问题,本文构建了一种方向—距离模型解决微地图辅助寻路时无法满足微地图特点(微内容) 的问题。首先, 描述了辅助寻路过程中符合微内容特点的表达要素:方向和距离,在微地图中给出了符合微内容特点的表现形式; 其次,针对路径数据的构成要素,通过构造方位角计算函数实现对路径数据的定量描述与建模,再依托八方向锥形模型对量化结果进行定性描述;最后,在此基础上,设计路径距离的计算方法,结合欧氏距离分别定义路段和节段的长度计算函数,并基于求和函数算出路径的总距离。实验表明:较之于现存方向关系计算模型,具有更优的时间复杂度, 能够有效避免计算冗余;相较于最短路径和基于地标权重的计算模型,不仅能够定量和定性描述空间方向关系,而且还能在用户寻路的动态过程中提供缺失的方向和距离信息。

     

    Abstract: Objectives: Existing models/ algorithms for the users of wayfinding focus on the landmark weight or the shortest route in we-map, which leads to the important information (e.g. direction and distance) was ignored and did not meet the certain requirements (e.g. the contents in maps is enough totally when decision-making using maps, but meanwhile, there is no redundant information to disturb their decision). To address this issue, a direction-distance model (DDM) for we-map assistance wayfinding is proposed, aiming at providing more detailed information to help the users to make decisions regarding wayfinding. Methods: First, the features of we-map were clarified, aiming at discussing representative relations between the characteristics of the we-map and aid wayfinding. According to the discussion results, it was compared with landmarks and direction-distance viewed as the core objects of we-map, and lastly the direction and distance relations were determined as core objects of we-map. Then, an example was discussed to explain how to meet a specific feature of we-map (i.e. the objects in we-map are totally enough when decision-making using maps, but meanwhile, there is no redundant information to disturb their decision). The specific reason why the traditional direction model cannot be utilized the we-maps, is the traditional direction model has redundant information disturbing users' decisions when wayfinding using maps. Last, a quantification model is built by calculating the azimuth of the path data, and the qualification model is developed to describe the results of the quantification model based on the eight-direction cone model. the method for calculation of the path distance is designed to obtain distance information, and the length function for the road segments and segments are defined combined with the Euclidean distance to compute path distance based on the sum function. Results: The experimental results show that, (1) proposed model can avoid the calculation redundancy, (2) the time complexity is superior compared with the existing spatial direction models, (3) spatial direction relations were described qualitatively and quantitively, as well as (4) the missing information of the direction and distance was added and provided during the dynamic process of the users' wayfinding. Conclusions: A direction-distance model was proposed to solve the problem of important information being ignored and certain requirements not being met. This model can provide more detailed direction and distance information for users when wayfinding using maps, but there is no other redundant information to disturb their decision.

     

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