Plotting change on maps

or how to replicate the New York Times presidential election shift map This week’s blogpost is a visualization demo replicating a popular map from last year. The map below shows the shift in voter margin between the 2016 and 2020 Presidential Elections by the two major political parties in the United States. The direction and […]

Introduction to Convergent Cross Mapping

This post is a follow-on to my previous post on Granger causality. Granger causality has well-known limitations.  As previously discussed, the test can only find “predictive causality” and not true causality. Further, a key requirement of Granger causality is separability, meaning the casual variable is independent of the variable that it influences. This separability tends […]

ggplot (Part 4) – Animated Geospatial Maps

Most of the time, we need to deal with complex systems that have several components, each with different properties and behavior. Usually, these properties vary with time and space, and understanding their spatiotemporal dynamics plays a key role in our understanding of the system performance and its vulnerabilities. Therefore, aggregation in time and space would […]

Networks on maps: exploring spatial connections using NetworkX and Basemap

This blogpost is about generating network graphs interlaid on spatial maps. I’ll be using the data provided by this paper (in the supplementary material) which estimates flows of food across US counties. All the code I’m using here can be found here. The dataset included in erl_14_8_084011_sd_3.csv of the supplementary material lists the tons of […]

Deeper Dive into Self-Organizing Maps (SOMs)

This blog post focuses on Self-Organizing Maps (SOMs) or Kohonen maps, first created by Teuvo Kohonen in the 1980s, and most recently introduced in Dave Gold’s latest blog post. SOMs are a type of artificial neural network (ANN) that are trained using unsupervised learning to produce a two-dimensional pattern representation of higher-dimensional datasets. SOMs are […]

Geospatial Mapping in R

Introduction Let me start this blog post by stating the obvious: Geospatial maps are interesting to look at and certainly make papers and presentations prettier and more impressive; however, those are not the only reasons that such maps exist. They are used to communicate various types of information including geographical locations of regions in the […]

Making Watershed Maps in Python

This post builds off of earlier posts by Jon Lamontagne and Jon Herman on making global maps in Python using matplotlib and basemap. However rather than making a global map, I’ll show how to zoom into a particular region, here the Red River basin in East Asia. To make these maps, you’ll need to have […]

The Linked Parallel Coordinate Plot with Linked Heatmap: A tool for simultaneous visualization of the objective and decision spaces

Introduction When making real world decisions, the individual decisions that comprise a solution are often equally important to decision makers as the objective values that are generated by the solution. When evaluating MOEA search results for such problems, analysts are in need of a tool that can allow them to simultaneously visualize solutions both in the objective and decision […]