GeoJSON is an open computer file format for encoding collections of simple geographical features along with their non-spatial attributes using JavaScript Object Notation. These files can be rendered easily within GitHub repositories. GitHub uses Leaflet.js to represent the data and OpenStreetMap for the underlying map data.
Spatial objects in R can be converted to GeoJSON with writeOGR from the rgdal package. For example, let’s display the meteorological stations of the SIAR network. (By the way, GitHub also supports rendering csv files)
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| library(sp) | |
| library(rgdal) | |
| setwd(tempdir()) | |
| download.file('https://raw.github.com/oscarperpinan/solar/gh-pages/data/SIAR.csv', 'siar.csv', method='wget') | |
| siar <- read.csv('siar.csv') | |
| summary(siar) | |
| siarSP <- SpatialPointsDataFrame(siar[,c(6, 7)], siar[,–c(6,7)]) | |
| writeOGR(siarSP, 'siar.geojson', 'siarSP', driver='GeoJSON') |
Now upload this file to a GitHub repository or create a Gist and voilá!
Another example, now using a larger dataset from the OpenPV project. From the GitHub help page:
If your map contains a large number of markers (roughly over 750), GitHub will automatically cluster nearby markers at higher zoom levels. Simply click the cluster or zoom in to see individual markers.
Related articles
- Gist meets GeoJSON (github.com)
- GeoJSON Previewing (github.com)
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