Census Data: Easier to Use

The Census Bureau has come a long way by offering census data in formats that can be easily imported into GIS software.  Whether at small or large scales, census data are vital to any analysis.  Of course, census data are free, even though some companies charge!  In addition, it is noteworthy to add census data can be ordered on DVD and includes user friendly tools to help extract the data you need.

Previously, and in still in some cases, attribute data would have to be joined with shapefiles.  The TIGER/Line page now features demographic and social data pre-joined to shapefiles and geodatabases for users that are not familiar with joining and managing such complex data. Click the map below to enlarge it.

US Population Counts by County and Cities with Population Greater than 250,000

Data from the American Community Survey (ACS) 5-year estimates can also be downloaded easily.  However, more can be done and more ready-to-use files could be created--resources allowing!  Hopefully, the Census will be able to maintain what they are doing and expand in the future.

Family Size (Purple/Red = Greater than 1 Standard Deviation above the mean, Blue = Below, No Color = Mean to 1 SD Above).  Both maps are derived from data in the Summary Demographic Profile 1.

Maps made with QGIS

The Road to Somewhere...

Open geographic data sources are great, but there are pitfalls...Take roads, for example.  Many GIS files for roads are created for different reasons and different periods of time.  Precision roads for navigation can be pricey.  The choice of road files can have a direct impact on the project you are working on.  The below shows roads from the U.S. Census Bureau (red) compared against the center line file from an open city data warehouse (black). The census data actually have a line/road going through the sports stadium.  In some places, red lines appear where there are no black lines and vice versa.