Digitally modeling human movement across the terrain finds its use in a number of practical application encompassing (but not limited to) search and rescue operations, escape routes planning, pedestrian evacuation times, and analysis of pedestrian health care facility accessibility in developing nations, to cite a few.
This type of modeling can be typically carried out with the use of commercial GIS software and/or via procedures that are not always easy to implement for the average user.
Dr Gianmarco Alberti, resident academic lecturer at the Department of Criminology, has developed software to streamline the modeling of walking-time distance. The software has been developed under the (free and open-source) R statistical programming language and currently implements 15 functions that help modeling the relation between walking time and the slope of the traversed terrain. The software output can be also easily imported into any GIS software for further analyses and visualizations.
Figure 1A shows the isochrones (lines of equal time) calculated around a source location (black solid dot) that might correspond to the place where a lost person has been last seen.
The isochrones indicate the space that can be covered by walking within the indicated time (in hours). The cost function employed is the well-known Tobler’s hiking equation (for off-path hiking), but many others are readily available from the software.
Figure 1B shows the same isochrones superimposed on a base-map showing the geographical area in more detail (east of Mt Etna, Sicily-Italy). Since, according to a number of studies, humans tend to overestimate terrain slopes by a surprisingly high margin, the software can also account for the cognitive overestimation of up-hill and down-hill movements.
In figure 2A and B, the isochrones are calculated to account for that overestimation.
With 729 downloads in April 2021, the software has been well received by users world-wide.