From time-to-time creating a basic map of the United States or other parts of the world to complement some statistical analysis is useful to emphasize a point. The maps package in R provide a good way to produce these these maps.  These maps axes are based on latitude and longitude ... [Read more...]

At last weekend’s Hack Ta Ville event here in Montreal, I joined up with some talented urban planners and web devs to realize Vélobstacles. The idea of the project is to crowd source information on cycling conditions around the city. As with any crowd sourcing project, we were ... [Read more...]

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Recently I found a post at FlowingData with a detailed tutorial to map connections with great circles with R. The tutorial of FlowingData is excellent, but I feel more comfortable with the sp classes and methods, and with the lattice and latticeExtra packages. Besides, I want to use the free ... [Read more...]

Since I look at mercury concentrations at different measurement stations in North America, visualization using a map with values (of your favourite parameter) plotted as colour-coded circles is quite useful. After some trial & error, here is some very basic code … Continue reading → [Read more...]

***This tutorial has been updated, please click here*** I frequently use R (a free software environment for statistical computing and graphics) for data analysis.  As almost all my data are spatial it is often good to produce a map of the results without having to export the data into another ... [Read more...]

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