Lab 2: Downloading and Mapping Data From Online

The goal of this Lab was to learn how to download and map data from the U.S. Census Bureau.

Methods:

I first performed an advanced search on the US Census Bureau’s website: http://factfinder2.census.gov/faces/nav/jsf/pages/searchresults.xhtml?refresh=t and Choose Topics > People > Basic Count/Estimate > Population Total. Then form the Geography tab I chose counties > County 050, Wisconsin > All Counties within Wisconsin. From here there data was offered to download in two data sets SF1 and ACS. SF1 datasets are the most basic based on the Decennial Census mandated every 10 years by the U.S. Constitution. SF1 provides an accurate count of all persons living in the U.S. in order to reassign seats for the House of Representatives. ACS (The American Community Survey) are detailed population estimates derived from a number of surveys across numerous geographic areas, so there is some error to the estimates as well. I choose and downloaded the P1 TOTAL POPULATION from the 2010 SF1 Dataset. From there I extracted the zip files. I then viewed the CSV files in MS Excel looking at the metadata and the tubular data: DEC_10_SF1_P1_with_ann.csv (P1) (which I saved as to Excel Workbook). I then downloaded a Wisconsin shapefile from the website and then unzipped the shapefile.

In ArcMap and confirmed that the data came over properly. I then opened the WI shapefile table and the P1 table and joined these using the common attribute GEO#id as the key. The shapefile was my destination table and the P1 table was the source table. I confirmed that the data join worked by opening the attribute table. From here I can now map the population data. In the WI shapefile symbology properties I choose quantities > graduated colors and selected a pleasing color scheme and number of classes. I choose the value to be mapped as D001 (Total Population). I also adjusted the projection of the data frame to one more appropriate for the State of Wisconsin: NAD 1983 (2011) Wisconsin TM (US Feet). From here I added other elements to complete the map.

 

I was also able to download a variable of my choice and I choose to download the P1 SEX BY AGE from the 2010 SF1 100% Data. I followed the same process with the TOTAL POPULATION data unzipping files and joining the data to the WI shapefile in order to map the data in a new data frame. For my value to be mapped I had to normalize the data I mapped D033 (Age 21) by D026 (Females) and choose to have my data shown as a percentage.

 

Results:

 

These are the finished maps of the data I downloaded from the US Census website. Overall the process was quite simple and even fun. I have Total Population by county on the left, and Total Percent of 21 year olds (Female) normalized by total female population by county. I thought that would be an interesting value to map based on my knowledge of where Wisconsin Universities and other major colleges in Wisconsin are located. Overall I am quite happy with the results of this lab.

 

Source: US Census Bureau - http://factfinder2.census.gov/faces/nav/jsf/pages/searchresults.xhtml?refresh=t