The app was built to find the least number and location of charging stations required in a region such that any person, from anywhere on the road in that region, should be within a certain driving distance from at least one charging station. We'd written a blog post about it.

To use the app, you need to supply three inputs:

• the region of interest
• the accessibility target, eg. one should never be more than 5 kms by road from a charging station from anywhere in the region
• candidate locations in the region for where we could set up charging stations

Using those inputs the app can run two sorts of optimisations for you:

• If you have a limit on the number of charging stations you can put, what are the best locations to put them at so you maximise accessibility
• If you have a coverage target such that a certain percent of the city must clear the accessibility target, what are the best locations to put stations in such that you meet that target with the minimum number of stations

That's pretty much the core functionality. The app further enables you to visualise the results of the optimisation, modify the inputs to the optimisation, point out scope for some more improvement, override the optimisation results and evaluate the impact of those changes, add new candidate locations, etc.

You can follow the instructions below and set it up to solve your problem for you. You could be optimising for bus stops, police stations, shops, or anything else which needs accessibility throughout a region.

Instructions on setting up and using here

This tool is built in R and heavily utilises the libraries - data.table, ggplot2, ggmap, GA, igraph, shiny, and datatable, among others. Apart from R, it heavily uses data from Open Street Maps and map tiles from Stamen.