Extended Classification Course Improves Road Intersection Detection from Low-Frequency GPS Trajectory Data

The requirements of location-based services have generated an increasing need for up-to-date digital road maps. However, traditional methods are expensive and time-consuming, requiring many skilled operators. The feasibility of using massive GPS trajectory data provides a cheap and quick means for generating and updating road maps. The detection of road intersections, being the critical component of a road map, is a key problem in map generation. Unfortunately, low sampling rates and high disparities are ubiquitous among floating car data (FCD), making road intersection detection from such GPS trajectories very challenging. In this paper, we extend a point clustering-based road intersection detection framework to include a post-classification course, which utilizes the geometric features of road intersections. First, we propose a novel turn-point position compensation algorithm, in order to improve the concentration of selected turn-points under low sampling rates. The initial detection results given by the clustering algorithm are recall-focused. Then, we rule out false detections in an extended classification course based on an image thinning algorithm. The detection results of the proposed method are quantitatively evaluated by matching with intersections from OpenStreetMap using a variety of distance thresholds. Compared with other methods, our approach can achieve a much higher recall rate and better overall performance, thereby better supporting map generation and other similar applications.

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Automatically Tracking Road Centerlines from Low-Frequency GPS Trajectory Data

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi10030122 ◽

2021 ◽

Vol 10 (3) ◽

pp. 122

Author(s):

Banqiao Chen ◽

Chibiao Ding ◽

Wenjuan Ren ◽

Guangluan Xu

Keyword(s):

Active Contour ◽

Low Frequency ◽

Tracking Algorithm ◽

Location Based Services ◽

Trajectory Data ◽

The Road ◽

Gps Trajectory Data ◽

Road Maps ◽

Gps Trajectory ◽

Refinement Algorithm

High-quality digital road maps are essential prerequisites of location-based services and smart city applications. The massive and accessible GPS trajectory data generated by mobile GPS devices provide a new means through which to generate maps. However, due to the low sampling rate and multi-level disparity problems, automatically generating road maps is challenging and the generated maps cannot yet meet commercial requirements. In this paper, we present a GPS trajectory data-based road tracking algorithm, including an active contour-based road centerline refinement algorithm as the necessary post-processing. First, the low-frequency trajectory data were transferred into a density estimation map representing the roads through a kernel density estimator, for a seeding algorithm to automatically generate the initial points of the road-tracking algorithm. Then, we present a template-matching-based road-direction extraction algorithm for the road trackers to conduct simple correction, based on local density information. Last, we present an active contour-based road centerline refinement algorithm, considering both the geometric information of roads and density information. The generated road map was quantitatively evaluated using maps offered by the OpenStreetMap. Compared to other methods, our approach could produce a higher quality map with fewer zig-zag roads, and therefore more accurately represents reality.

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An Automatic Method for Detection and Update of Additive Changes in Road Network with GPS Trajectory Data

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi8090411 ◽

2019 ◽

Vol 8 (9) ◽

pp. 411 ◽

Cited By ~ 3

Author(s):

Tang ◽

Deng ◽

Huang ◽

Liu ◽

Chen

Keyword(s):

Road Network ◽

Sampling Rate ◽

Quality Data ◽

Automatic Method ◽

Trajectory Data ◽

The Road ◽

High Sampling Rate ◽

Map Generation ◽

Gps Trajectory Data ◽

Gps Trajectory

Ubiquitous trajectory data provides new opportunities for production and update of the road network. A number of methods have been proposed for road network construction and update based on trajectory data. However, existing methods were mainly focused on reconstruction of the existing road network, and the update of newly added roads was not given much attention. Besides, most of existing methods were designed for high sampling rate trajectory data, while the commonly available GPS trajectory data are usually low-quality data with noise, low sampling rates, and uneven spatial distributions. In this paper, we present an automatic method for detection and update of newly added roads based on the common low-quality trajectory data. First, additive changes (i.e., newly added roads) are detected using a point-to-segment matching algorithm. Then, the geometric structures of new roads are constructed based on a newly developed decomposition-combination map generation algorithm. Finally, the detected new roads are refined and combined with the original road network. Seven trajectory data were used to test the proposed method. Experiments show that the proposed method can successfully detect the additive changes and generate a road network which updates efficiently.

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Estimating Urban Road GPS Environment Friendliness with Bus Trajectories: A City-Scale Approach

Sensors ◽

10.3390/s20061580 ◽

2020 ◽

Vol 20 (6) ◽

pp. 1580

Author(s):

Liantao Ma ◽

Chaohe Zhang ◽

Yasha Wang ◽

Guangju Peng ◽

Chao Chen ◽

...

Keyword(s):

Urban Areas ◽

Negative Impact ◽

Field Tests ◽

Location Based Services ◽

Trajectory Data ◽

Gps Positioning ◽

Urban Road ◽

Gps Trajectory Data ◽

Gps Trajectory ◽

Road Segments

GPS is taken as the most prevalent positioning system in practice. However, in urban areas, as the GPS satellite signal could be blocked by buildings, the GPS positioning is not accurate due to multi-path errors. Estimating the negative impact of urban environments on GPS accuracy, that is the GPS environment friendliness (GEF) in this paper, will help to predict the GPS errors in different road segments. It enhances user experiences of location-based services and helps to determine where to deploy auxiliary assistant positioning devices. In this paper, we propose a method of processing and analysing massive historical bus GPS trajectory data to estimate the urban road GEF integrated with the contextual information of roads. First, our approach takes full advantage of the particular feature that bus routes are fixed to improve the performance of map matching. In order to estimate the GEF of all roads fairly and reasonably, the method estimates the GPS positioning error of each bus on the roads that are not covered by its route, by taking POIinformation, tag information of roads, and building layout information into account. Finally, we utilize a weighted estimation strategy to calculate the GEF of each road based on the GPS positioning performance of all buses. Based on one month of GPS trajectory data of 4835 buses within the second ring road in Chengdu, China, we estimate the GEF of 8831 different road segments and verify the rationality of the results by satellite maps, street views, and field tests.

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