The Challenge of Obtaining Ground Truth for GPS Processing

Stopher, Peter; Shen, Li; Liu, Wen; Ahmed, Asif

doi:10.1016/j.trpro.2015.12.018

Cited by 18 publications

(10 citation statements)

References 13 publications

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“…Other trip information needs to be derived or estimated in the further processing of the raw GPS data. Therefore, a lot of research has contributed to methods to assess the transportation mode(s) and the trip purpose [53][54][55][56][57][58][59][60], based on the speed and accelerometer data during the trip, additional GIS-data (e.g., about public transportation networks and rail networks), land use maps, etc. [61,62].…”

Section: Base Datamentioning

confidence: 99%

Measuring Delays for Bicycles at Signalized Intersections Using Smartphone GPS Tracking Data

Gillis

Gautama

Gheluwe

et al. 2020

IJGI

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The article describes an application of global positioning system (GPS) tracking data (floating bike data) for measuring delays for cyclists at signalized intersections. For selected intersections, we used trip data collected by smartphone tracking to calculate the average delay for cyclists by interpolation between GPS locations before and after the intersection. The outcomes were proven to be stable for different strategies in selecting the GPS locations used for calculation, although GPS locations too close to the intersection tended to lead to an underestimation of the delay. Therefore, the sample frequency of the GPS tracking data is an important parameter to ensure that suitable GPS locations are available before and after the intersection. The calculated delays are realistic values, compared to the theoretically expected values, which are often applied because of the lack of observed data. For some of the analyzed intersections, however, the calculated delays lay outside of the expected range, possibly because the statistics assumed a random arrival rate of cyclists. This condition may not be met when, for example, bicycles arrive in platoons because of an upstream intersection. This justifies that GPS-based delays can form a valuable addition to the theoretically expected values.

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Section: Base Datamentioning

confidence: 99%

Measuring Delays for Bicycles at Signalized Intersections Using Smartphone GPS Tracking Data

Gillis

Gautama

Gheluwe

et al. 2020

IJGI

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“…The remote sensing data were first corrected for geometric and radiometric corrections as required for standard remote sensing imageries for quality enhancement and assessment (Burrough, 1996). The imageries were thereafter georeferenced in ArcGGIS software (version 10.5) by merging the coordinates of known points that were obtained from the existing topographical maps of the area, and confirmed with the use of global positioning system (GPS, Germin etrex version) on the physical structure as described by Stopher et al (2015). Also, the Landsat 8 imagery was classified using supervised classification (based on Maximum likelihood Classification algorithm) into different dominant landuse system following Anderson (1976)'s scheme for landuse/land cover classification.…”

Section: Discussionmentioning

confidence: 99%

Urban flood event and associated damage in the Benue valley, Nigeria

2021

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Flooding events in the Lower Benue valley of Nigeria are often associated with huge damage to properties and loss of life in the adjoining communities. Specific objective of this study is to evaluate the impact of 2017 flood event as typical of the study area. Method used was an integrated environmental approach that combines analysis of rainfall and discharge data with social surveys, remote sensing and geographical information system. Standardized Precipitation Index (SPI), Precipitation Concentration Index (PCI) as well as flood damage curves were analysed with landuse/cover change and soil data to establish the nature of the flood and its impacts. Result showed that the flood in the study area is essentially saturation overland flow, which is more associated with saturation-excess than infiltration excess flow, and that the flood events are recurrent and predictable. 85% of the affected residents are however poor, earning an equivalent of US $4.3 daily, and live in non-reinforced concrete masonry (64%) and wooden buildings (24%). Many of the affected communities lived within flood plain and most buildings were structurally deficient. Victims received no compensation, and the properties were generally uninsured. The study recommends extensive flood control policy for the area and similar floodprone communities.

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“…This discourse indicates the relevance of capturing the potentially rich empirical data on actual choice strategies used by passengers from dedicated smartphone-based survey apps. Thus, drawing on these opportunities, in this paper we analyse data obtained from a user-mediated prompted recall (Stopher et al 2015) mobile application-based travel survey (for details regarding this survey, for example, an extensive description of survey sample properties, see Berggren et al 2019). In addition to user-revised trip trajectories and activities, data from the surveywhich was carried out in the regional PT system of Scania, Sweden-also include stated passenger planning and optimisation strategies and the usage rate of departure time information ahead of PT trips based on context-aware notification prompting (Turner et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Effects from usage of pre-trip information and passenger scheduling strategies on waiting times in public transport: an empirical survey based on a dedicated smartphone application

et al. 2019

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Waiting times are important indicators of the degree of travel time optimisation and other behavioural traits among public transport (PT) passengers. As previous studies have shown, the level and usage of pre-trip information regarding schedule or realtime departures are important factors that influence the potential to realise travel time savings by enabling PT passengers to optimise waiting times. Most empirical evidence regarding the revealed PT travel behaviour concerning information levels is based on manual interviews or traditional travel surveys, in which there is a risk that the actual context of where and when the choice of departure time was made is not taken into account. This paper reports the results of a travel survey based on a dedicated smartphone application applied in a field study in a Swedish mid-size urban and regional context. Context-aware notification prompting was used to allow respondents to state their use of pre-trip information as well as whether they had pre-planned their trip and how contingent planning aids were used for time optimisation. The implications on passenger waiting times of the use of information regarding departure times by passengers were emphasised during analyses of the resulting data, along with personal characteristics, in which auxiliary sources such as timetable data and Automatic Vehicle Location were utilised to determine ground truth trip trajectories and trip-contextual factors. The results indicate the significance of having access to pre-trip information, especially for long trips above one hour's duration, in order to pre-plan and thereby optimise waiting times. In addition, the use and source of pre-trip information differ among age and gender groups. Trip purpose and time of day to some extent determine waiting times and choice of trip optimisation strategy (arrival or departure time).

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The Challenge of Obtaining Ground Truth for GPS Processing

Cited by 18 publications

References 13 publications

Measuring Delays for Bicycles at Signalized Intersections Using Smartphone GPS Tracking Data

Measuring Delays for Bicycles at Signalized Intersections Using Smartphone GPS Tracking Data

Urban flood event and associated damage in the Benue valley, Nigeria

Effects from usage of pre-trip information and passenger scheduling strategies on waiting times in public transport: an empirical survey based on a dedicated smartphone application

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