scholarly journals Estimating experienced racial segregation in US cities using large-scale GPS data

2021 ◽  
Vol 118 (46) ◽  
pp. e2026160118
Author(s):  
Susan Athey ◽  
Billy Ferguson ◽  
Matthew Gentzkow ◽  
Tobias Schmidt
Keyword(s):  
Global Positioning System ◽  
Large Scale ◽  
Racial Segregation ◽  
Gps Data ◽  
Income Mobility ◽  
Positioning System ◽  
Global Positioning ◽  
Highly Correlated ◽  
Transit Use ◽  
Us Cities

We estimate a measure of segregation, experienced isolation, that captures individuals’ exposure to diverse others in the places they visit over the course of their days. Using Global Positioning System (GPS) data collected from smartphones, we measure experienced isolation by race. We find that the isolation individuals experience is substantially lower than standard residential isolation measures would suggest but that experienced isolation and residential isolation are highly correlated across cities. Experienced isolation is lower relative to residential isolation in denser, wealthier, more educated cities with high levels of public transit use and is also negatively correlated with income mobility.

scholarly journals The Unanticipated Challenges Associated With Implementing an Observational Study Protocol in a Large-Scale Physical Activity and Global Positioning System Data Collection (Preprint)

2017 ◽  
Author(s):  
Paul McCrorie ◽  
David Walker ◽  
Anne Ellaway
Keyword(s):  
Physical Activity ◽  
Data Collection ◽  
Global Positioning System ◽  
Large Scale ◽  
Gps Data ◽  
Positioning System ◽  
Consent Forms ◽  
Global Positioning ◽  
Objectively Measured ◽  
Objectively Measured Physical Activity

BACKGROUND Large-scale primary data collections are complex, costly, and time-consuming. Study protocols for trial-based research are now commonplace, with a growing number of similar pieces of work being published on observational research. However, useful additions to the literature base are publications that describe the issues and challenges faced while conducting observational studies. These can provide researchers with insightful knowledge that can inform funding proposals or project development work. OBJECTIVES In this study, we identify and reflectively discuss the unforeseen or often unpublished issues associated with organizing and implementing a large-scale objectively measured physical activity and global positioning system (GPS) data collection. METHODS The SPACES (Studying Physical Activity in Children’s Environments across Scotland) study was designed to collect objectively measured physical activity and GPS data from 10- to 11-year-old children across Scotland, using a postal delivery method. The 3 main phases of the project (recruitment, delivery of project materials, and data collection and processing) are described within a 2-stage framework: (1) intended design and (2) implementation of the intended design. RESULTS Unanticipated challenges arose, which influenced the data collection process; these encompass four main impact categories: (1) cost, budget, and funding; (2) project timeline; (3) participation and engagement; and (4) data challenges. The main unforeseen issues that impacted our timeline included the informed consent process for children under the age of 18 years; the use of, and coordination with, the postal service to deliver study information and equipment; and the variability associated with when participants began data collection and the time taken to send devices and consent forms back (1-12 months). Unanticipated budgetary issues included the identification of some study materials (AC power adapter) not fitting through letterboxes, as well as the employment of fieldworkers to increase recruitment and the return of consent forms. Finally, we encountered data issues when processing physical activity and GPS data that had been initiated across daylight saving time. CONCLUSIONS We present learning points and recommendations that may benefit future studies of similar methodology in their early stages of development.

scholarly journals Parking Places to Moped-Style Scooter Sharing Services Using GIS Location-Allocation Models and GPS Data

2021 ◽  
Vol 10 (4) ◽  
pp. 230
Author(s):  
Onel Pérez-Fernández ◽  
Juan Carlos García-Palomares
Keyword(s):  
Global Positioning System ◽  
Catchment Area ◽  
Public Spaces ◽  
Gps Data ◽  
Positioning System ◽  
Urban Centers ◽  
Location Allocation ◽  
Global Positioning ◽  
The City

Moped-style scooters are one of the most popular systems of micro-mobility. They are undoubtedly good for the city, as they promote forms of environmentally-friendly mobility, in which flexibility helps prevent traffic build-up in the urban centers where they operate. However, their increasing numbers are also generating conflicts as a result of the bad behavior of users, their unwarranted use in public spaces, and above all their parking. This paper proposes a methodology for finding parking spaces for shared motorcycle services using Geographic information system (GIS) location-allocation models and Global Positioning System (GPS) data. We used the center of Madrid and data from the company Muving (one of the city’s main operators) for our case study. As well as finding the location of parking spaces for motorbikes, our analysis examines how the varying distribution of demand over the course of the day affects the demand allocated to parking spaces. The results demonstrate how reserving a relatively small number of parking spaces for scooters makes it possible to capture over 70% of journeys in the catchment area. The daily variations in the distribution of demand slightly reduce the efficiency of the network of parking spaces in the morning and increase it at night, when demand is strongly focused on the most central areas.

scholarly journals Concurrent Measurement of Global Positioning System and Event-Based Physical Activity Data: A Methodological Framework for Integration

2020 ◽  
pp. 1-14
Author(s):  
Anna M.J. Iveson ◽  
Malcolm H. Granat ◽  
Brian M. Ellis ◽  
Philippa M. Dall
Keyword(s):  
Physical Activity ◽  
Outcome Measures ◽  
Global Positioning System ◽  
Gps Data ◽  
Positioning System ◽  
Activity Data ◽  
Data Set ◽  
Physical Activity Data ◽  
Global Positioning ◽  
Event Based

Objective: Global positioning system (GPS) data can add context to physical activity data and have previously been integrated with epoch-based physical activity data. The current study aimed to develop a framework for integrating GPS data and event-based physical activity data (suitable for assessing patterns of behavior). Methods: A convenience data set of concurrent GPS (AMOD) and physical activity (activPAL) data were collected from 69 adults. The GPS data were (semi)regularly sampled every 5 s. The physical activity data output was presented as walking events, which are continuous periods of walking with a time-stamped start time and duration (to nearest 0.1 s). The GPS outcome measures and the potential correspondence of their timing with walking events were identified and a framework was developed describing data integration for each combination of GPS outcome and walking event correspondence. Results: The GPS outcome measures were categorized as those deriving from a single GPS point (e.g., location) or from the difference between successive GPS points (e.g., distance), and could be categorical, scale, or rate outcomes. Walking events were categorized as having zero (13% of walking events, 3% of walking duration), or one or more (52% of walking events, 75% of walking duration) GPS points occurring during the event. Additionally, some walking events did not have GPS points suitably close to allow calculation of outcome measures (31% of walking events, 22% of walking duration). The framework required different integration approaches for each GPS outcome type, and walking events containing zero or more than one GPS points.

Subsidence is determined in the heart of the Central Valley using Post Processed Static and Precise Point Positioning techniques

2020 ◽  
Vol 14 (1) ◽  
pp. 113-118 ◽  
Author(s):  
Y. Facio ◽  
M. Berber
Keyword(s):  
Data Processing ◽  
Global Positioning System ◽  
Precise Point Positioning ◽  
Central Valley ◽  
Gps Data ◽  
Positioning System ◽  
Online Services ◽  
Global Positioning ◽  
System Data ◽  
Point Positioning

AbstractPost Processed Static (PPS) and Precise Point Positioning (PPP) techniques are not new; however, they have been refined over the decades. As such, today these techniques are offered online via GPS (Global Positioning System) data processing services. In this study, one Post Processed Static (OPUS) and one Precise Point Positioning (CSRS-PPP) technique is used to process 24 h GPS data for a CORS (Continuously Operating Reference Stations) station (P565) duration of year 2016. By analyzing the results sent by these two online services, subsidence is determined for the location of CORS station, P565, as 3–4 cm for the entire year of 2016. In addition, precision of these two techniques is determined as ∼2 cm. Accuracy of PPS and PPP results is 0.46 cm and 1.21 cm, respectively. Additionally, these two techniques are compared and variations between them is determined as 2.5 cm.

Variations of the Precipitation Water Vapor by Using GPS Data Triggered Raining in the Summer of Thailand

2015 ◽  
Vol 804 ◽  
pp. 279-282
Author(s):  
Nithiwatthn Choosakul
Keyword(s):  
Water Vapor ◽  
Global Positioning System ◽  
Gps Data ◽  
Positioning System ◽  
Global Positioning ◽  
Precipitation Water ◽  
High Level

The variation of water vapor can be detected from the Global Positioning System (GPS) data. The GPS signal was delayed when propagated through the wet atmosphere. The delayed signal can be retrieved into Precipitation Water Vapor (PWV) data. The GPS data of CUSV station from 2009 to 2012 were used in this research. The results showed that the PWV varied during the summer of Thailand. The PWV were slightly increased from 20 mm at the beginning of the season to 40 mm at the end of season. The increased PWV data were shown as linear line. A slope of the linear line may relate with the amount of the cumulative rain in the season. The steeper line might relate to the great number of raining in the end of the season, otherwise, the fairly gradual line might relate to the raining at any time in the season. The high level of PWV up to around 33 mm could induce the rain in the summer of Thailand.

scholarly journals Quantification of the Accuracy of Low Priced GPS Receivers for Crash Location

2010 ◽  
Author(s):  
Thobias Sando ◽  
Renatus Mussa ◽  
John Sobanjo ◽  
Lisa Spainhour
Keyword(s):  
Global Positioning System ◽  
Time Of Day ◽  
Gps Data ◽  
Positioning System ◽  
Gps Receiver ◽  
Accuracy Improvement ◽  
Gps Receivers ◽  
Location Data ◽  
Global Positioning ◽  
Potential Tool

Global positioning system (GPS) has been identified as a potential tool for capturing crash location data. This study quantifies factors that could affect the accuracy of GPS receivers. The results showed that GPS receiver orientation, site obstructions, and weather have significant effects on the accuracy of GPS receivers. Time of day and number of satellites were not found to significantly affect the accuracy of GPS receivers. HDOP values of 1.2 or less were found to be adequate for crash location purposes. An accuracy improvement of 20.7% was realized by filtering GPS data based on HDOP values.

scholarly journals KAJIAN KESESUAIAN LAHAN BUDIDAYA TAMBAK DI WILAYAH PESISIR KABUPATEN PANGKEP, SULAWESI SELATAN DENGAN APLIKASI SISTEM INFORMASI GEOGRAFIS

2016 ◽  
Vol 8 (3) ◽  
pp. 479
Author(s):  
Utojo Utojo ◽  
Erna Ratnawati
Keyword(s):  
Global Positioning System ◽  
Gps Data ◽  
Positioning System ◽  
Global Positioning

Penelitian ini memanfaatkan teknologi sistem informasi geografis (SIG) untukmenentukan lahan yang sesuai untuk budidaya tambak di Kabupaten Pangkep, Sulawesi Selatan. Data sekunder yang digunakan berupa data iklim, data pasang surut, peta Rupabumi Indonesia wilayah Pangkep skala 1:50.000, dan peta batimetri skala 1:200.000. Data primer diperoleh dengan metode survai di lokasi penelitian yaitu kualitas air dan tanah tambak. Setiap lokasi pengambilan contoh ditentukan posisi koordinatnya dengan global positioning system (GPS). Data lapangan (fisiko-kimia air dan tanah), data sekunder, dan data citra satelit digital ALOS AVNIR-2 tersebut dikumpulkan dan dianal isis secara spasial menggunakan SIG. Hasil analisis menunjukkan bahwa tambak yang ada di wilayah pesisir Kabupaten Pangkep mencapai luas 12.199 ha. Dari luas tersebut, yang tergolong berkesesuaian tinggi (22 ha) di Kecamatan Segeri, yang berkesesuaian sedang (6.675 ha), dan rendah (5.502 ha), tersebar di Kecamatan Mandalle, Segeri, Marang, Labakkang, Bungoro, Pangkajene, dan Minasatene, sedangkan yang tidak sesuai (418 ha), tersebar di wilayah pesisir Kecamatan Marang, Labakkang, dan Minasatene.

scholarly journals Harmonic Analysis of Multipath Index Time Series in GPS Stations

2015 ◽  
Vol 16 (1) ◽  
pp. 71
Author(s):  
Eniuce Menezes de Souza ◽  
Daniele Barroca Marra Alves ◽  
Fernanda Lang Schumacher
Keyword(s):  
Time Series ◽  
Harmonic Analysis ◽  
Global Positioning System ◽  
Seasonal Variations ◽  
Gps Data ◽  
Positioning System ◽  
Fisher Test ◽  
Multipath Effect ◽  
Global Positioning ◽  
Index Time Series

The identification of the cyclical and seasonal variations can be veryimportant in time series. In this paper, the aim is to identify the presence ofcyclical or seasonal variations in the indices of the multipath effect on continuousGPS (Global Positioning System) stations. Due to the model used to obtain theseindices, there should not have cyclical variations in these series, at least due to themultipath effect. In order to identify the presence of cyclical variations in theseseries, correlograms and Fourier periodograms were analyzed. The Fisher test forseasonality was applied to confirm the presence of statistical significant seasonality.In addition, harmonic models were adjusted to check in which months of the yearthe cyclical effects are occurring in the multipath indices. The possible causes ofthese effects are pointed out, which will direct the upcoming investigations, as wellas the analysis and correlations of other series. The importance of this analysisis mainly due to the fact that errors in the collected signals of these stations willdirectly influence the accuracy of the results of the whole community that directlyor indirectly uses GPS data.

scholarly journals PERUNTUKAN KAWASAN PESISIR KABUPATEN MAROS, SULAWESI SELATAN SEBAGAI LOKASI PENGEMBANGAN BUDIDAYA TAMBAK RAMAH LINGKUNGAN

2011 ◽  
Vol 6 (2) ◽  
pp. 325
Author(s):  
Utojo Utojo ◽  
Akhmad Mustafa ◽  
Hasnawi Hasnawi
Keyword(s):  
Global Positioning System ◽  
Gps Data ◽  
Positioning System ◽  
Global Positioning

Penelitian ini bertujuan untuk mendapatkan potensi kawasan pesisir di Kabupaten Maros, Sulawesi Selatan yang layak sebagai lokasi pengembangan budidaya tambak ramah lingkungan dengan menggunakan teknologi Sistem Informasi Geografi (SIG). Data sekunder yang didapatkan berupa data iklim, data pasang surut, peta Rupabumi Indonesia kawasan Maros skala 1:50.000, citra digital landsat ALOS AVNIR-2 akuisisi 21 Juni 2008 dan peta bathimetri skala 1:200.000. Data primer didapatkan di lokasi penelitian dengan metode survai berupa kualitas air dan tanah tambak. Sebaran stasiun pengamatan dilakukan secara acak dan sistematik, di mana setiap lokasi pengambilan contoh ditentukan posisi koordinatnya dengan alat Global Positioning System (GPS). Data primer dan sekunder serta data citra satelit digital tersebut dikumpulkan dan dianalisis secara spasial menggunakan SIG. Berdasarkan hasil survai dan evaluasi kelayakan lahan budidaya tambak ramah lingkungan di wilayah pesisir Maros seluas 10.249,1 ha. Yang berkelayakan sedang (3.111,4 ha) dan rendah (7.137,7 ha), tersebar di Kecamatan Bontoa, Lau, Marusu, dan Maros Baru, masing-masing dituangkan dalam peta prospektif skala 1:50.000.<br /><br />

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