By Suqin Yan
Abstract:
This paper presents my research about trajectory studies of mobile objects; it is based on the previously studies of trajectory, to improve a new definition of trajectory of mobile objects on landscape. It’s related to mobile objects and their activity, accessibility. Because of people’s daily activity construct their live, different person with different properties, like age, gender, occupation etc, these differences caused different activity pattern on landscape, different activities caused various trajectories in both spatial and temporal dimension.
This report gives trajectory a new definition, like constraint one trajectory made by one person on one day. Different activity makes different trajectory, in order to identify trajectories of people’s daily activity, the trip is defined which is the sub-trajectory, it used to describe the segment of each activity during a day; and the stop concept are used to define the start point and end point of a trip, stop is a location where is no movement considering the activity, it used to separate the trajectory into several trips. In this case, it’s easier to study people’s daily movements. A E-R model used to modelling trajectory, and the model will be implemented in MS access. In the model there are 5 entities are involved, PEOPLE, TRAJECOTRY, TRIP, STOP and TRACKPOINT, the trackpoint entity store the GPS data from a field work, based on the demand of the model, the data will be processing and storage.
The model test work will be done to make sure the model is able to retrieve people’s daily movements. There use 6 queries to test the model, these queries involve all the interest information of trajectory, like the trajectory from different people and in different time period, travel time, travel length, stop location, stop purpose etc.
The model also should be supported to analyse people’s activity and accessibility from their trajectory, the method is visualizing the interest trajectory in ArcMap, and located the trips and stops on land use map, based on the land use class to deduce some knowledge about people’s movement activity and accessibility, e.g. based on the land use class, to identify the type of start point and end point of a trip, to define the activity of the trip.
A field work is set up in this research; it used to collect trajectory data to test the model. The study area is Wageningen, the Netherlands; and sample group are students of wageningen university, and the field work lasts 9 days. In these days, every volunteer takes a GPS device when they outside, the GPS is capable to record people’s movement continuously and automatically, get a trajectory data stream over time, like {(x1,y1,t1), (x2,y2,t2), (x3,y3,t3), …}, where x, y are spatial coordinates of a location point, and t is the time on that point. Based on demand of the model to handle this kind of data, then store the data and implement the model in MS Access, set queries to test the model.