2010 CENSUS DATA : DOWNLOADING FOR USE IN ARCGIS 10

Transcription

1 6/29/2012 GIS RESEARCH AND MAP COLLECTION 2010 CENSUS DATA : DOWNLOADING FOR USE IN ARCGIS 10

2 Downloading Census boundary files and accompanying Census attribute tables are both common tasks in GIS. The following tutorial will guide you step by step how to download and join together these two data sources using ArcMap 10. * This tutorial is for users who are familiar with ESRI s ArcMap software. * This tutorial will take approximately1 hour to complete. Obtaining GIS Census Geography Files 1. Managing your data and storing it in easy to find folders with descriptive names is always important with any GIS project. Before beginning this tutorial you will need to: a. Create a folder somewhere in your personal workspace entitled Census_2010_tutorial b. Create two subfolders entitled Census_Geography and Census_Data 2. Go the U.S. Census website and click on the Geography tab at the top of the page. Select TIGER 3. Click on TIGER/Line Shapefiles & Files 4. Click on the link for 2010 TIGER\Line Shapefiles Main Page 5. Click on Download Shapefiles 2

3 6. Under Select a layer type: Choose Census Tracts and click submit 7. In the next window make sure you choose Census Tract (2010) and then select Indiana from the pull down window and click on submit 3

4 8. For this tutorial we will be downloading all the counties in Indiana so choose all counties in one state-based file and click Download 9. The dataset will come in a compressed.zip file. You will need to save it to your Census_Geography folder and then unzip it. *You will also notice if you view the files attribute table that no actual census demographic information is attached other than fields identifying the geography. That brings us to our next step: Downloading Census Attribute Data from American FactFinder This part of the tutorial will show you how to download census attribute data from the US Census Bureau s American FactFinder website. 1. If necessary, reopen your web browser and navigate to the US Census web site Click on the Data tab at the top of the window and choose American Factfinder 3. Click on Geographies left column, which will bring up a new Select Geographies window 4. Type Indiana in the search box and click Go 4

5 5. Under the Geography Filter Options in the left column, choose Census Tract for your geographic type 6. In the Geography Results list that pops up after you chose Census Tract, checkmark All Census Tracts within Indiana and then click Add. If you do not see this option then start over from step 3 5

6 7. Close the Select Geographies overlay window 8. The Your Selections column in the upper left hand window should look like the image above. If it doesn t, clear your selections and start over from step 3 9. Click Topics in the left hand column, then expand the Dataset selection and choose 2010 SF1 100% Data and close the Select Topics box 6

7 10. For this tutorial we want a simple table with few variables, so type Race in the box entitled Narrow you search and click GO 11. Scroll through the resulting tables until you find P3 Race and checkmark this table. 7

8 12. Click on Download and follow the instructions. Your file will be built and then you will click on another download option 13. Save this file in your Census_Data folder and unzip the files. 8

9 *Now that the census data has been downloaded there is still some prep work to do before it can be joined to your census block group shapefile in ArcGIS Desktop, which brings us to our next step in the tutorial: Opening the Census File in Excel and Convert it to a Database File Compatible with ArcGIS 1. Browse to your Census_Data folder and open the downloaded.csv table by double clicking on it 2. The formatting of the Excel table is not compatible with ArcGIS Desktop and will have to be modified a. Tables in ArcGIS Desktop can only have 1 header row. i. Choose one header row and rename your columns to something that will make sense in ArcMap. Be sure to follow the ArcMap guidelines (no titles over 10 characters long, no spaces between words, and no special characters except for the underscore (_)). ii. Delete the other header rows. Your data should start on row 2. b. The GEOID2 column should be formatted as text. Right click on the column letter, choose Format Cells, and choose Text from the list. i. Note: If your GEOID2 data starts with a 0, you will have to add the zero back manually after formatting the row to Text. To do this use the concatenate function: 9

10 c. Often these tables come with way more information than what is needed for individual GIS projects. Delete any columns of data that you don t need. Be sure NOT to delete the GEOID2 row. 3. Save you file as an Excel Workbook (.xlsx) with a recognizable name such as IndianaRaceData_2010.xlsx. Joining the Excel Data File to the Census Boundary Shapefile in ArcGIS Desktop 1. Open a blank ArcMap document 2. Add the Census Tracts geography data (tl_2010_18_tract10.shp) to the map document 3. Add the Census Data from excel to the map document a. You will only add the individual worksheet. 4. GEOID2 will be the field that you use to join the excel data into your Shapefile. a. Right click on the tl_2010_18_tract10 shapefile and choose Joins and Relates and then choose Join 10

11 5. In the Join Data dialog box, choose Join attributes from a table and fill in the boxes to match the graphic below: 6. Open your Census Geography shapefile (tl_2010_18_tract10.shp) to make sure join was successful. You should see the data from your Excel file when you scroll to the right 11

12 7. This join between the census geography and census data will only be kept in this ArcMap document. If you open the shapefile in a new ArcMap document you will have to rejoin the geography to the data. To permanently save the join you will need to export this shapefile as a new shapefile. To do this, right click on tl_2010_18_tract10.shp in the table of contacts, and choose Data -> Export Data 8. In the Export Data dialog box choose the folder where you want to permanently save the joined data and hit OK 9. You are now ready to create maps of your data. Please complete this tutorial by filling out the user feedback form found at: 12