## Displaying Images in Tableau (with some help from Python)

One of the cool things you can do with Tableau is define every pixel from an image. This allows you to create interesting visualizations as described below. Before we get started, let’s first understand some fundamental concepts about digital images. DIGITAL IMAGE A digital image is a matrix made out of pixels (the smallest element on a screen). In the figure below we present an image of fruits and vegetables. It can be observed that when we zoom into a portion of the image

## Plotting Functions – Part 2: Using Polar Coordinates

This is part 2 of a post where we demonstrate how to plot functions in Tableau. Part 1 can be seen here. In this section we are focused on using Polar coordinates. This is a helpful system for recreating shapes that have some sort of circular shape. In Cartesian coordinates, each point is represented by an (x,y) pair; however, in the Polar coordinates, each point is represented by a (r,θ) pair. A few things to keep in mind about angles (θ). A circle has 360 degrees, which

## Plotting Functions – Part 1: Using Cartesian Coordinates

In this post, we will demonstrate a method for plotting two-dimensional functions in Tableau. We will present examples in both Cartesian and Polar coordinates. This post focuses on the Cartesian system and the follow-up post focuses on the Polar Coordinate system. Our goal is to demonstrate how to plot functions as the ones shown below: Let’s start by reviewing a few definitions. 2D Cartesian Coordinates, is a system where every point on a plane is defined by a pair of value

## Create Map Paths Using Great Circles

A typical map is a two-dimensional representation of a three-dimensional sphere. When we draw paths, we know that the shortest distance between two points is a straight line. Nevertheless, the shortest path on the surface of a sphere does not necessarily look like a straight line on a two-dimensional map. In this post, we explain how to draw paths that connect two locations on a map based on the shortest distance between them using Tableau. We use a concept called great-ci

## How to Make Circular and Polygon Radial Charts

I recently got inspired from viewing a dashboard designed by Adam Crahen, where he created a Circular Radial Chart based on data about Gender Disparity in Australia *. Doing some research I came up with a few posts that explain how to create these types of charts, such as here and here. In this post, my goal is to expand this type of chart from circular to a polygon shape using Tableau. We will use the line drawing capabilities to create each of the bars. A Polygon Radial Ch

## Rotationally Invariant Charts

Recently I was reading an interesting article by Nate Silver. In it there is a chart that compares the Post-debate “instant” poll, net margin (horizontal axis) versus the Gain or loss in horse-race poll after debate (vertical axis). The data comes from CNN and Gallup polls of presidential debates since 1984. A copy of the chart is observed below. What caught my attention is that the chart is “rotationally invariant”. In other words, the chart looks the same when it is rotated