Last Modified Date: 12 Jun 2018
In dual axis maps, each of the two axis' marks can be set separately. This allows for a variety of layering of information. The most effective of which seems to be a choropleth, or filled, map that is colored by some region dimension. Using the Sample - World Bank Indicators data source.
Step 1: Create Our Region Map
- Ctrl + Click on Country / Region and Region.
- Use Show me to create a map.
- Drag Region from the row shelf to the color portion of the marks card.
Step 2: Shade our map by some measure
- Hold down ctrl and drag Latitude (generated) from the row shelf onto the row shelf.
- Note: the marks card now has more options for each of our two maps.
- Click on the bottom Latitude (generated) on the marks card.
- Drag your measure of choice onto the color tab of the bottom Latitude (generated) marks card. In this example: G: Legal rights (0 = weak)
- Click on the color part of the bottom Latitude (generated) marks card, and click Edit Colors...
- Select Gray from the Palette dropdown.
- Click Ok.
Step 3: Combine the two maps
- Right click on the second Latitude (generated) pill on the row shelf.
- Select Dual Axis.
- Click on the color part of the bottom Latitude (generated) marks card.
- Play with transparency to get the right balance of color and shading.