1. A quick visit to Treasure Island
Let’s discover custom mapping in a short visit to Treasure island. Let’s inspect the datasets.
We have a pirate map with 3000 by 2000px resolution.
Additionally, we have the treasure island file with locations and their X and Y coordinates (for now, filled with the map’s dimensions).
The detail file contains further information on the locations, including the order of our visit. The data sets are linked by location field.
We begin by dropping the X and Y coordinates into Columns and Rows to create a grid. Next, we will set up the axes to represent the size of our pirate map: X from 0 to 3000 and Y from 0 to 2000.
This will help Tableau scale the canvas to the precise size of our map.
Now we will upload the background picture. We open the Map menu, select Background Images, and add our file to the treasure island data model.
We add the picture and set up the X right coordinate to 3000 and Y top to 2000, leaving the left and bottom as 0.
The map has vivid colors, so we will apply some washout. Apply, and our map is ready.
Next, we need to find the coordinates of our locations. We need Home, Pirates’ Nest, Safe Harbour, Treasure, and the Unknown grave.
We find the coordinates on the map by right-clicking locations to annotate the spot, getting the precise X and Y coordinates.
For the sake of the demo, we have already collected all the data points and are ready for analysis.
To visualize these locations, we will drop the location on the label, increase the size and mark them as black, filled circles.
Let’s also drop the Level of Danger field onto the color. We’ll change the color palette to display the most dangerous places in red and the least dangerous ones in green.
How about the Order field? It indicates the order of our trip through the land of Pirates.
We want to plot it on the map as a line, but our visualization already contains shapes (the circles). We need to overlay it with a new graph - the line chart.
We duplicate the X coordinates, and in the second set of Marks card, we will add Order to the detail, removing all other marks and changing the visualization to a line.
When we do that, a Path Marks card appears.
By dropping the Order to the path, the line on the map will display our journey in the right order.
Let’s click on Path to learn more. What happens when we change it to Step?
That looks like a snake path! Nice, but we will stick with the first option.
We now use a dual axis to combine both charts, swap the order of both SUM(X) arguments to bring the circles to the front, and enlarge the view to Entire View. We will also hide the axes.
To add the cherry on the cake, we’ll animate our trip through the island.
But first, we will go to the Format menu and click on Animations, to switch workbook default animations OFF. This allows us to set up our own manual animations in the next steps.
We can now add our animation. To do so, we drag discrete dimensions, such as dates or Order, to the Pages.
See that menu on the right? When we move the slider, the point of the map moves!
Wouldn’t it be nice to track that circle?
To add trailing marks, we need to switch the Mark card from Line to circle and apply Show history, enabling All history, showing both Trails and Marks, and adapting their format to a colored dotted line.
We now press Play, lean back, and relax - Tableau will play out our journey through the pirate island!
Now it’s your turn! We will come back to the real world, exploring an equally cool dataset on an interesting museum in the exercises.
2. Let's practice!