Creating a Standard Map View
When creating a map view, Tableau automatically adds the generated Latitude and Longitude fields to the Rows and Columns shelves and places a selected geographic field on Detail on the Marks card.
The marks in the view correspond to the field on Detail. For example, if the State field is used in the view, there is a single mark for each state in your data. As you add more geographic fields to Detail on the Marks card, the marks in the view will be broken down by the members of those fields.
Now, let us have a look at what happens when you want to plot more complex data using the Show Me menu to create a map. Using the Superstore Sales data set, create a map that uses state and product category from the dimensions shelf and sales from the measures shelf. Multi-select the fields and use the Show Me button to pick the symbol map. The resulting map is displayed in Figure 5.1
Figure 5.1: Symbol map created using Show Me
You can see that Tableau already placed five pills in various places to create the symbol map. Click on the Show Me menu again and select the filled map. In fact, double-clicking on any field that Tableau recognizes as a geographic entity will result in a map being created, in which the marks plotted will show the center-point geocoding of the selected entity—even if you don’t select any other dimensions or measures. This is why you should lean on Show Me to build maps— it’s much faster than manually dragging the fields. When you make that change, Tableau places category on the row shelf. This results in three maps being displayed. Each map displays a specific product category. Dragging the category pill from the row shelf to the filter shelf (then turning that filter into a Quick Filter) results in the filled map as shown in figure 5.2.
Figure 5.2: Filled map created with show me
Color encoding is used to show the sales values in each state. The sales amount labels were turned on by clicking on the label button on the marks card and selecting the show mark label option. The map’s appearance was edited to remove background images for Geographic’s that have no sales. To edit the map style, use the main menu option for map and choose the map options menu. The map options menu is seen in figure 5.3
Figure 5.3: Map options menu
>>For the filled map in figure 5.3, the map washout was changed to one hundred percent. This hides map features from view. The areas bordering the United States are blank. If any state lacked sales, it would be blank as well. At the top of the background section, the gray map type is selected. There are two other map types: normal and dark. Figure 5.4 shows the differences between normal, gray, and dark backgrounds.
>>The map options menu in Figure 5.3 also allows you to add more details to the map by adding more map layers. These options allow you to color-encode geographic shapes in the map using state, county, zip code, or census block level of detail. In the United States, there are thirty different census data sets related to population, race, occupation, households, and housing. If you want to override Tableau’s standard map settings with the new options you’ve selected, click the Make Default button at the bottom of the menu.
Figure 5.4: Standard map background
|Data Visualization and Dashboarding Fundamentals|
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