In this lab we were put to the task of downloading U.S. 2010 Census Data from the Census Bureau and making two maps from that data of Wisconsin. We first had to go the Census Bureau Website and find the data that we wanted to map. We first had to download a map of Wisconsin showing us all the different Counties. The first data set that then took was the 2010 SF1 100% Total Population Data. This is compiled based the on Decennial Census that is mandated every 10 years in order to reapportion seats in the House of Representatives. We took the Total Population data and downloaded the shapefile to our Student Coursework folder. In downloaded as a Zip File so we had to extract that file to our lab folder. In that data contained two Microsoft Excel files containing the data and the metadata which tells us what some of the short speak pertains to within the data file.
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| Selecting the Total Population data from the 2010 SF1 100% Dataset |
From here we opened up ArcMap and expanded the map of Wisconsin containing the different counties. Then we dragged the Population Data onto our map. The skill we learned now was how to join two tables in Arc in order to then take the data from one table and map it on the other. To do this we joined the two tables based on a common field. This was GEO_ID which represented the different counties. Then due to some issues we had to add another field into the table and go to the field calculator of which then we were able to link the new field with an existing field so that we can map the data.
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| The two tables we joined, notice how there is two seperate GEO#id fields. |
Now that we figured out how to get the data to be mapped, we selected the population as the variable we wanted to map and made some cartographic decision as to how many classes we wanted to have and what color scheme worked out the best. I selected to have seven classes so that Northern Wisconsin wasn't one big unsightly blob of low population counties. Since the three major cities in Wisconsin (Milwaukee, Madison, Green Bay) are so large, they really stand out in the map, which is good but before I made that cartographic decision Northern Wisconsin was irrelevant. Now if you look at the map at the very bottom of the blog post you can see the major cities pop out but you can also see that there are three or four different population classes towards the North.
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| The map on the left show five different classes while the finished product on the right shows seven. |
This concluded the brunt of the lab. From here we selected another variable we wanted to map from the Census Bureau and went through all the steps to download, join tables, and how to make cartographically pleasing decisions on classification and color schemes. After we completed both maps we put them into a layout where we added the essentials of a map such as a title, scale, legend, north arrow, and the author name. I also added a basemap to my layout to make it more pleasing to the eye and to add a better sense of place. I decided to use to the light gray canvas basemap instead of the typical world imagery basemap. I thought that they light gray made more sense because the world imagery would distract your eyes and since it was not a physical variable map, I thought that the canvas was more appropriate for a human variable map.
I can definitely say that after spending the time to learn what this lab was teaching, I am very comfortable with downloading data from the census and joining the tables in order to make these maps.
