isodist

mad-science@ricepo

This package can compute isodistance polygons based on driving distance.

Getting Started

$ npm install isodist

In order to run isodist, you will need to download an *.osm file corresponding to the region where you want to do your computation. Geofabrik is a good source of these files.

You need to place your OSM files into the isodist/osrm directory (create one if it does not exist). Then run the following command to generate .osrm files:

$ npm run prepare

Finally, you are good to go! In order to generate the graph above, you will need indiana.osrm and run the following:

$ isodist --lon=-86.893386 --lat=40.417202 --stops=2,5,7 --resolution=0.1 --hexsize=0.5 --deburr --osrm=in

Command Line Arguments

--lat

Required.

Latitude of the origin point.

--lon

Required.

Longitude of the origin point.

--stops

Required.

Distances at which to compute isodistance polygons. For example, to compute isodistance polygons at 1, 2, 5 and 10 miles, use --stops=1,2,5,10

--osrm

Required.

Name of the .osrm file you wish to use for routing.

-o, --output

Optional, default: output.json

Specifies the file where to output resulting GeoJSON FeatureCollection.

-r, --resolution

Optional, default: 0.2

Sampling resolution of the underlying point grid. Larger values will result in less precise results but much faster processing. Smaller values will produce more precise results, but will require exponentially more processing time and memory.

-h, --hexsize

Optional, default: 0.5

Size of hex grid cells that isodistances are fitted onto. Passing a 0 value will disable hex grid fitting.

--deburr

Optional, default: none

This flag instructs isodist to remove isolated "islands" from isodistance geometries.