<i>R</i> Package <b>gdistance</b>: Distances and Routes on Geographical Grids

Etten, Jacob van

doi:10.18637/jss.v076.i13

Cited by 433 publications

(346 citation statements)

References 15 publications

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“…Habitat suitability models were used to estimate the permeability from the banding station to surrounding raster cells for each study landscape using the package gDistance (functions transition, geoCorrection, and accCost; Van Etten, 2015). We calculated a transition matrix between adjacent raster cells (queen's case) weighted by the inverse of the habitat suitability rasters-thus suitability provides a measure of conductance between cells (see McRae et al, 2008).…”

Section: Methodsmentioning

confidence: 99%

Dispersal in the Urban Matrix: Assessing the Influence of Landscape Permeability on the Settlement Patterns of Breeding Songbirds

et al. 2017

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The ability of organisms to disperse across urban landscapes is theorized to be constrained by habitat fragmentation. While previous research has shown the distribution of forest patches is a determinant of dispersal patterns among forest-obligate bird species, the impacts of habitat distribution on the dispersal of "urban-adapted" species, has yet to be examined. Here, we use capture-reencounter data of birds banded over a 9-year period at six banding stations in greater Washington, DC to assess dispersal in four species of songbirds and a translocation experiment to examine the influence of land cover on movement. Point count and land cover data were used to construct habitat suitability and landscape permeability surfaces, with the latter representing potential travels costs from the capture location to the surrounding landscape. To assess how dispersal processes are affected by urban land cover, we searched for previously banded birds at sampling locations within 1.5 km of each banding station and compared the distribution of sampling locations with and without observations of previously-banded birds. We found evidence that settlement of two of four focal species, the Northern Cardinal (Cardinalis cardinalis) and Gray Catbird (Dumetella carolinensis), was more likely in sites with high relative permeability. To experimentally explore the consequences of the urban matrix habitat on movement, we attached radio transmitters to male Cardinals, translocated individuals 1.5 km across high-intensity urban, suburban, and forested landscapes, and recorded the time to return to their territory. Return time was dependent on land cover with Cardinals translocated across suburban habitats returning significantly faster than those moved across the other two land use classes. Combined, our findings suggest that, even among some "urban-adapted" species, dispersal within urban environments may be influenced by landscape structure and composition.

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Section: Methodsmentioning

confidence: 99%

Dispersal in the Urban Matrix: Assessing the Influence of Landscape Permeability on the Settlement Patterns of Breeding Songbirds

et al. 2017

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“…Given that the IHS2/3 GPS data followed a displacement scheme similar to the DHS, the 10 km buffer size was deemed appropriate to minimize displacement bias in raster-based covariate definitions for the IHS data. Market access was defined as the shortest distance (km) from an IHS cluster to the nearest city along major roads, and was calculated using the gdistance and fields packages in R (Nychka et al 2014; van Etten 2014). The roads shapefile used for these calculations was obtained from DIVA-GIS (http://www.diva-gis.org/).…”

Section: Methodsmentioning

confidence: 99%

Land use and household energy dynamics in Malawi

Jagger

Perez-Heydrich

2016

Environ. Res. Lett.

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Interventions to mitigate household air pollution (HAP) from cooking with solid fuels often fail to take into account the role of access to freely available woodfuels in determining fuel choice and willingness to adopt clean cooking technologies, key factors in mitigating the burden of HAP. We use national-scale remote sensing data on land use land cover change, and population representative data from two waves of the Malawi Living Standards Measurement Survey to explore the relationship between land use change and the type of fuel households use, time spent collecting fuel, and expenditures on fuel, hypothesizing that land use dynamics influence household-level choice of primary cooking fuel. We find considerable heterogeneity with respect to regeneration and deforestation/degradation dynamics and evidence of spatial clustering. We find that regeneration of forests and woodlands increases the share of households that collect fuelwood, whereas deforestation and degradation lead households to purchase fuelwood. We also find that relatively large share of land under woody savannah or degraded forest (vs. fully stocked forest) increases fuel collection time. Areas with regeneration happening at broader scale experience increases in fuel expenditures. Our findings have implications for the spatial targeting of interventions designed to mitigate household air pollution.

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“…The travel time distance between sublocations was calculated with R's gDistance package [95]. As inputs, we used OpenStreetMap data [96] for the road network and waterways, the SRTMv4.1 digital elevation model [97] for deriving slope values in the terrain, and Africover data [82] for the land cover.…”

Section: Availability Modelmentioning

confidence: 99%

Accounting for the Boundary Problem at Subnational Level: The Supply–Demand Balance of Biomass Cooking Fuels in Kitui County, Kenya

Bär

Ehrensperger

2018

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Abstract:In sub-Saharan Africa, the high demand for wood-based cooking fuels calls for urgent policy action to steer the cooking energy sector towards more sustainability. While the subnational scale is growing in importance for policy planning, current energy assessments still only consider individual entities without taking into account resource flows. Ignoring flows of biomass cooking fuels in supply-demand assessments is a system boundary problem that can lead to misleading policy recommendations. In this paper, we tackle the boundary problem in subnational supply-demand assessments and provide a tool to support knowledge-based decision-making on the management of biomass cooking fuels in sub-Saharan Africa. Using Kitui County as a case study, we developed and tested an approach consisting of a supply model, local demand model, balance model, availability model, and adjusted balance model. The balance model only considers local fuel supplies and demand, whereas the adjusted balance model also considers external demand, which reduces the locally available supply of fuel. The results show that fuel demand and supply are spatially heterogeneous and vary between wood-based and non-woody fuels, and that the transport distance of fuels strongly affects local fuel availability and determines whether the supply-demand balance is positive or negative. We conclude that subnational energy policies should consider geographical distribution of supply and demand, aim to increase the fuel mix, consider external demand in supply-demand assessments, and differentiate between fuels for self-consumption and the market.

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R Package gdistance: Distances and Routes on Geographical Grids

Cited by 433 publications

References 15 publications

Dispersal in the Urban Matrix: Assessing the Influence of Landscape Permeability on the Settlement Patterns of Breeding Songbirds

Dispersal in the Urban Matrix: Assessing the Influence of Landscape Permeability on the Settlement Patterns of Breeding Songbirds

Land use and household energy dynamics in Malawi

Accounting for the Boundary Problem at Subnational Level: The Supply–Demand Balance of Biomass Cooking Fuels in Kitui County, Kenya

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