Archives |
|
This page archives old articles posted on the research page. |
Processing raw data from Global Positioning Systems without additional information
N Schuessler and KW Axhausen
Source: Transportation Research Record | Year: 2009 | Volume: 2105 | Pages: 28-36
Since the first Global Positioning System (GPS) studies in the mid-1990s, this method of surveying individual travel behavior has gained attention in transport research. Compared with classic travel survey methods, GPS studies offer researchers benefits of more accurate and reliable information. At the same time, the participants' burden is reduced substantially if the GPS data collection does not involve time-consuming questions. However, without additional information, such as modes and trip purposes, extensive postprocessing is required to derive data that can be used for analysis and model estimation. The corresponding procedures are an ongoing research issue. This paper describes a postprocessing procedure needing no input other than the most basic GPS raw data: three-dimensional positions and the corresponding time stamps. First, the data are thoroughly cleaned and smoothed. Second, trips and activities are determined. Third, the trips are segmented into single-mode stages, and the transport mode for each of the stages is identified. The procedure is applied to GPS records collected in the Swiss cities of Zurich, Winterthur, and Geneva. A total of 4,882 participants carried an on-person GPS receiver for an average of 6.65 days. The results are compared with the Swiss Microcensus 2005 to demonstrate that derived data are ready for further applications, such as discrete choice model estimations.
POSTED ON: 16 Nov 2009 22:11:49
POSTED BY: Administration
Combining GPS with heart rate monitoring to measure physical activity in children: A feasibility study
JS Duncan, HM Badland & G Schofield
Source: Journal of Science & Medicine in Sport | Year: 2009 | Volume: 12 | Issue: 5 | Pages: 583-585
The recent development of global positioning system (GPS) receivers with integrated heart rate (HR) monitoring has provided a new method for estimating the energy expenditure associated with children's movement. The purpose of this feasibility study was to trial a combination of GPS surveillance and HR monitoring in 39 primary-aged children from New Zealand. Spatial ... (more)
POSTED ON: 09 Nov 2009 20:11:19
POSTED BY: Administration
A criterion method for measuring route distance in physically active commuting
P Schantz & E Stigell
Source: Medicine & Science in Sports & Exercise | Year: 2009 | Volume: 41 | Issue: 2 | Pages: 472-478
PURPOSE: There is a need for accurate, reliable, and feasible methods for determining route distances in physically active transportation. The aim of this study, therefore, was to scrutinize if distances of commuting routes drawn by physically active commuters and measured with a digital curvimetric distance measurement device could serve such a purpose.
METHODS: ... (more)
POSTED ON: 09 Nov 2009 20:11:57
POSTED BY: Administration
Deriving and validating trip purposes and travel modes for multi-day GPS-based travel surveys: A large-scale application in the Netherlands
W Bohte & K Maat
Source: Transportation Research Part C | Year: 2009 | Volume: 17 | Issue: 3 | Pages: 285-297
In the past few decades, travel patterns have become more complex and policy makers demand more detailed information. As a result, conventional data collection methods seem no longer adequate to satisfy all data needs. Travel researchers around the world are currently experimenting with different Global Positioning System (GPS)-based data collection methods. An ... (more)
POSTED ON: 09 Nov 2009 20:11:34
POSTED BY: Administration
Accuracy of iPhone locations: A comparison of Assisted GPS, WiFi, and Cellular Positioning
PA Zandbergen
Source: Transactions in GIS | Year: 2009 | Volume: 13 | Issue: S1 | Pages: 5-26
The 3G iPhone was the first consumer device to provide a seamless integration of three positioning technologies: Assisted GPS (A-GPS), WiFi positioning and cellular network positioning. This study presents an evaluation of the accuracy of locations obtained using these three positioning modes on the 3G iPhone. A-GPS locations were validated using surveyed benchmarks ... (more)