How to draw connecting routes on map with R and great circles

This post explains how to draw connection lines between several localizations on a map, using R. The method proposed here relies on the use of the gcIntermediate function from the geosphere package. Instead of making straight lines, it offers to draw the shortest routes, using great circles. A special care is given for situations where cities are very far from each other and where the shortest connection thus passes behind the map. Continue reading

4 tricks for working with R, Leaflet and Shiny

I recently worked on a dataviz project involving Shiny and the Leaflet library. In this post I give 4 handy tricks we used to improve the app: 1/ how to use leaflet native widgets 2/ how to trigger an action when user clicks on map 3/ how to add a research bar on your map 4/ how to propose a “geolocalize me” button. For each trick, a reproducible code snippet is provided, so you just have to copy and paste it to reproduce the image.

Trick 1: use leaflet native control widget

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The Wordcloud2 library

A word cloud (or tag cloud) is a visual representation of text data. Tags are usually single words, and the importance of each tag is shown with font size or color. This mode of representation is useful for quickly perceiving the most prominent terms in a list and determine their relative prominences. In R, two libraries will allow you to create wordclouds: Wordcloud and Wordcloud2. In this post I will introduce the main features of the awesome Wordcloud2 library developed by Chiffon Lang.

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