This document is last updated on .

Final Project: In Depth - edited by Aaron Lee

Merging Files

To acquire the data, I went to nationalatlas.gov, clicked on "Map Layers", clicked on the "People: Crime, Economy, Health, Energy Consumption..." tab and viewed map layer descriptions for Census 1980, Census 1990, and Census 2000. For each decade, the census data was displayed in separate tables. The National Atlas recommends downloading county boundaries for each decade. The tables are under "ce####.tar.gz" and the shapefiles are under "co####p020.tar.gz" All of the .gz files are unzipped and then extracted.

Cleaning Up the Shapefiles

I opened up ArcMap in order to use the editor tool. I added each "co####p020" shapefile to the table of contents. I started with the "Select by Attributes" tool and typed "STATE" LIKE '%PR%' OR "STATE" LIKE '%VI%'. This query selects shapefiles associated with Puerto Rico and the Virgin Islands, which do not have any census data in the table. I then started an editing session and opened the shapefile's attribute table where I followed the procedure of deleting the selected attributes and saving the edits. I then selected the features that did not have an associated county (they're bodies of water), deleted those features, and exited the editing session. After deleting these features, I accessed the dissolve tool by accessing the toolbox to click on "Data Management Tools", "Generalization", and finally, "Dissolve." I placed the shapefile as the input feature and then named the output feature "###States_dissolve.shp." I checked "STATE" and STATE_FIPS" for Dissolve_Field(s). I then selected "AREA", "PERIMETER", and "SQUARE_MIL" for Statistics Field(s) and have all of them associated with "SUM" statistic type. I checked "Create multipart features" and did not check "Unsplit lines". After the entire procedure is done and then clicked OK.

Cleaning Up the Tables

I added each "ce####t" to the table of contents. I opened each of their attributes, and double clicked on "SQ_MILE_80" and made sure that it starts from 0 where there were 51 features which included D.C. I then utilized the "Table to Table (Conversion)" tool (toolbox flow: Conversion tools, To Geodatabase, Table to Table). I selected the "ce####t" table for input rows; the output location would be a folder listed under the data (in my case, ####_Census; the output table would be the new name (in this case, ####_States_Census), and leave the rest of the fields alone and clicked OK.

Joining Shapefiles with Tables

After cleaning up the tables, I right clicked on "####States_dissolve.shp", went to joins, and selected Join Data. In the tool, I chose "Join attributes from a table", "STATE_FIPS", "1980_States_Census", checked "Show the attribute tables of layers in this list", chose "FIPS", and "Keep all records." I then exported the layer as a new shapefile, which I named each shapefile "full####States.shp."

This is my final project. Enjoy!