High resolution global gridded data for use in population studies

Lloyd, Christopher T.; Sorichetta, Alessandro; Tatem, Andrew J.

doi:10.1038/sdata.2017.1

Cited by 266 publications

(191 citation statements)

References 48 publications

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“…The construction of the slope layer is useful to human population studies because population densities tend to be much lower on steep slopes. Similarly, the construction of the topography layer is useful because population densities tend to be lowest at the highest elevations (Lloyd et al, 2017). Moreover, population densities are all related to landcover, infrastructure and climatic regimes, and therefore the additional layers are also potentially valuable inputs as covariates to population modelling efforts (Lloyd et al, 2017).…”

Section: Methodsmentioning

confidence: 99%

“…Pixel area tiles are supplied as 100m tiles only. Additional spatial data layers that are incorporated into the archive are similarly standardised to match the grid definition and coastlines of the country ID base grid (Lloyd et al, 2017).…”

Section: Methodsmentioning

confidence: 99%

“…An Ubuntu Linux OS (14.04 LTS, Trusty Tahr) installation is utilised, with PostgreSQL 9.1 (PostgreSQL GDG, 2016) and PostGIS 2.0 (PostGIS PSC, 2016) database software from which spatial relational data can be exported. Osm2pgsql (OSMF, 2016) is an OSM specific software that is used to load OSM data into databases (Lloyd et al, 2017). Subsequent database access, processing, and filtering (on the Windows platform) is provided by QGIS 2.18.4 (QGIS project, 2017) and Spatialite v4.3.0a, including the Spatalite graphical user interface (GUI) 2.0.0 (Furieri, 2016) software.…”

Section: Data Processing Softwarementioning

confidence: 99%

“…The alpha version of the Archive (Lloyd et al, 2017) has been produced using a methodology that more frequently employs proprietary software (i.e. ESRI ArcMap).…”

Section: Data Processing Softwarementioning

confidence: 99%

“…Consequently, to support population mapping applications in the future there is a need for standardised grid definitions, standardised (contiguous) country boundaries and coastlines, and covariate layers representing different time periods that match these and that are regularly updated -all created at fine spatial resolutions (Lloyd, Sorichetta, & Tatem, 2017). To begin to meet such needs, the WorldPop Project is producing a beta version open access archive of 3 and 30 arcsecond spatial resolution gridded datasets.…”

Section: Introductionmentioning

confidence: 99%

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High Resolution Global Gridded Data for Use in Population Studies

Lloyd

2017

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:Open access geospatial data represent a range of metrics relevant to global human population mapping at fine spatial scales. Detailed and contemporary spatial datasets that accurately describe population distributions are vital in order to measure impacts of population growth, monitor change, and plan interventions. To construct such datasets the harmonisation of geospatial data layers is a prerequisite because layer specifications differ widely.To this end the WorldPop Project is producing an open access archive of 3 and 30 arc-second (~100m and ~1km, respectively) resolution gridded data in a predominantly open source environment, using OSGEO4W utilities. Five tiled raster datasets form the basis of the archive: (i) Viewfinder Panoramas topography clipped to CIESIN national level administrative coastlines; (ii) a matching ISO 3166 country identification grid; (iii) country area; (iv) pixel area; (v) and slope layer. Further layers will include transport networks, landcover, urban extent, nightlights, climate, travel time to major cities, forest stand change, livestock densities, vegetation indices, and waterways. We here describe the base datasets and the production methodology in development. The alpha version of the archive can be downloaded both from the WorldPop Dataverse Repository and the WorldPop Project website. The improved and expanded beta version of the archive is in development for release next year, and will offer significantly improved standardisation of country boundaries, and inland water boundaries (forthcoming), to global census unit data.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Data Processing Softwarementioning

confidence: 99%

“…The alpha version of the Archive (Lloyd et al, 2017) has been produced using a methodology that more frequently employs proprietary software (i.e. ESRI ArcMap).…”

Section: Data Processing Softwarementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High Resolution Global Gridded Data for Use in Population Studies

Lloyd

2017

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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Geographic Accessibility and Availability of Radiotherapy in Ghana

et al. 2022

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ImportanceRadiotherapy is critical for comprehensive cancer care, but there are large gaps in access. Within Ghana, data on radiotherapy availability and on the relationship between distance and access are unknown.ObjectivesTo estimate the gaps in radiotherapy machine availability in Ghana and to describe the association between distance and access to care.Design, Setting, and ParticipantsThis is a cross-sectional, population-based study of radiotherapy delivery in Ghana in 2020 and model-based analysis of radiotherapy demand and the radiotherapy utilization rate (RUR) using the Global Task Force on Radiotherapy for Cancer Control investment framework.ExposuresReceipt of radiotherapy and the number of radiotherapy courses delivered.Main Outcomes and MeasuresGeocoded location of patients receiving external beam radiotherapy (EBRT); median Euclidean distance from the district centroids to the nearest radiotherapy centers; proportion of population living within geographic buffer zones of 100, 150, and 200 km; additional capacity required for optimal utilization; and geographic accessibility after strategic location of a radiotherapy facility in an underserviced region.ResultsA total of 2883 patients underwent EBRT courses in 2020, with an actual RUR of 11%. Based on an optimal RUR of 48%, 11 524 patients had an indication for radiotherapy, indicating that only 23% of patients received treatment. An investment of 23 additional EBRT machines would be required to meet demand. The median Euclidean distance from the district centroids to the nearest radiotherapy facility was 110.6 km (range, 0.62-513.2 km). The proportion of the total population living within a radius of 100, 150 and 200 km of a radiotherapy facility was 47%, 61% and 70%, respectively. A new radiotherapy facility in the northern regional capital would reduce the median of Euclidean distance by 10% to 99.4 km (range, 0.62-267.7 km) and increase proportion of the total population living within a radius of 100, 150 and 200 km to 53%, 69% and 84%, respectively. The greatest benefit was seen in regions in the northern half of Ghana.Conclusions and RelevanceIn this cross-sectional study of geographic accessibility and availability of radiotherapy, Ghana had major national deficits of radiotherapy capacity, with significant geographic disparities among regions. Well-planned infrastructure scale-up that accounts for the population distribution could improve radiotherapy accessibility.

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