From the course: Tableau 10 Essential Training

Creating a basic map - Tableau Tutorial

From the course: Tableau 10 Essential Training

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Creating a basic map

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- [Narrator] When you have geographic data, one of the best ways to summarize it is by creating a map. In this movie, I will show you how to map US geological survey data which contains both latitude and longitude values. My sample file is the CreateMap workbook and you can find it in the chapter 12 folder of your exercise files collection. I have connected to a workbook that contains United States Geological Survey Quake Data. If I want to take a look at the data, I can go to the Data menu, point to My Data Source at the bottom of the Menu and then click View Data. And when I do, I see that I have the various IDs and if I scroll over to the right, I'll see that I have columns for Latitude and Longitude as well as Magnitude. And those are the three columns that I will use. Latitude and Longitude will be my dimensions and Magnitude will be my measure. I'll go ahead and close the Data View. And add the fields to my visualization. The first thing I need to do is convert Latitude and Longitude which are numbers and therefore perceived as measures by Tableau into dimensions so I will right click Longitude 'cause that's the one my mouse pointer's over right now. And just about half way on the shortcut menu, I'll click Convert to Dimension. When I do, Longitude goes from Measures and you can see it here now in Dimensions. I'll right click Latitude and do the same thing, Converting it to a Dimension. Now I will open the Show Me task pane, just to see what the different visualizations are. I want to create a map and when I hover my mouse pointer over the first map on row two, I see that for symbol maps, I need to have one Dimension and zero or two Measures. So that means that I need to add Latitude and Longitude and then also Magnitude. So I will go to the Data tab and drag Latitude to the Rows area, I'll also drag Longitude to the Rows area. Now, rather than using my current type of visualization, I will click the map. And you can see immediately that I now have the locations of my individual earthquakes. So I'll close the Show Me panel. And you can see that the dots represent the locations. However, I don't have anything dealing with the Magnitude so I don't know how large these quakes were. To do that, I can go to the Measures panel and drag Magnitude to Size. And you can see that the individual dots indicating specific earthquakes have changed but the relative size is pretty close. One way to change that is to right click, the Sum of Magnitude, this is on the Marks Card. And change it from Continuous to Discreet. And when you do, you see that you get a much more meaningful or at least differentiated indication of the size of the earthquakes. And you can see the relative size here in this card on the right side. If I want to see a 3.4 earthquake, then I can click it and click Keep Only. And when I do, I see that there have been one, two, three, four 3.4 earthquakes. And if I press Ctrl+Z to go back, then all of my data comes back in. It can be a little confusing on how you convert Latitude and Longitude data into a map-able resource for Tableau 10. What you need to remember is that Latitude and Longitude need to be Dimensions. And remember, you convert them to Dimensions by right clicking them and then clicking Convert to Dimension. And you can change the size of each of the indicators by dragging Magnitude or something similar, perhaps Square Miles to the Size icon on the Marks Card. And if the differences aren't enough, you can right click it, it being the pill on the Marks Card for your data and change it from Continuous to Discreet.

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