U.S. Census Data U.S. Census Data Options for downloading and importing

data into ArcMap

Treg ChristopherOct 31, 2008

Types of Census DataTypes of Census Data Decennial Census

◦ SF1:Sex,Age,Race,Hshld income, size Info for each field at:

http://factfinder.census.gov/servlet/MetadataBrowserServlet?type=dataset&id=DEC_2000_SF1_U&_lang=en

◦ SF2:Similar info as SF1 but detailed for each of 200+ ethnicities Guide for finding specific info:

http://ssdc.ucsd.edu/ssdc/cen2k/raceguide.pdf

◦ SF3:Long form…intensive info from a sample of people from each Block http://factfinder.census.gov/servlet/MetadataBrowserServlet?type=dataset&id=DEC_2000_SF3_U&_l

ang=en

◦ SF4:Similar info as SF3 but detailed for many ethnicities Community Surveys Economic Surveys

Census Geographic FilesCensus Geographic Files TIGER (Topologically Integrated Geographic Encoding and

Referencing )◦ Source:

Variety of sources but mainly from1:100,000 USGS topo maps◦ Positional Accuracy (Horizontal):

National Map Accuracy standards for 1:100k is approx +/- 167 feet

Relationship betw/ scale and acuuracy: http://www.tceq.state.tx.us/gis/natmap.html

◦ Most sources have already converted these TIGER files into a more usable format (e.g. shapefiles) If not:

Use Toolbox in ArcMap (Need ArcInfo workstation installed) Use a 3rd Party conversion software

◦ Refer to: http://www.census.gov/geo/www/tiger/overview.html and http://www.census.gov/geo/www/tiger/faq-index.html for more info

Census UnitsCensus Units

Block Group ID: 12 Digits= State (2) + County (3) + Tract (6) + BG (1) So you can always aggregate data and analyses from the single BG ID

Data Sources for Census Data Sources for Census DataDataESRI Geography Network

◦http://www.esri.com/data/download/census2000_tigerline/index.html

Federal GIS Clearinghouse ◦http://gos2.geodata.gov

Vermont Spatial Data (at VCGI)◦http://www.vcgi.org/

U.S. Census◦American Factfinder at

www.census.gov

ESRI Geography NetworkESRI Geography Network

Project WorkspaceProject Workspace

Census SF1 Table

Census Shapefile

Joining Tables to Joining Tables to ShapefilesShapefiles

Download data for

entire state

Download data for AOI

(Area of Interest)

VCGI Data for Entire StateVCGI Data for Entire State

VCGI Custom SelectionVCGI Custom Selection

VCGI Custom Selection of B-VCGI Custom Selection of B-tonton

Data from Data from www.census.govwww.census.gov

or

Table Types in ArcMapTable Types in ArcMapTables can be added to ArcMap if

they are:◦Dbf files◦From a database (e.g. Access)

(Doesn’t have to be an ESRI personal geodatabase)

DBF not available in Office 2007!◦Import xls or csv file directly into

Access◦Import xls or csv file into Open Office

and save as dbf

Import CSV file into Excel or Import CSV file into Excel or AccessAccess

Can usually skip this page unless Excel sets wrong

data type

ID showing

as # instead of text

Boundary Files from Boundary Files from www.census.govwww.census.gov

Don’t use these..they have

generalized boundaries

(explained at: http://www.census.gov/ge

o/www/cob/scale.html )

Appending Census Appending Census BoundariesBoundaries

What to do if you want a single, large coverage from multiple, smaller areas◦Copy the largest GIS file

(shapefile,pgdb,file gdb) and rename (e.g. “MasterCensusBnd”)

◦Use the Append command in ArcMap to merge these multiple files

Comments for ProjectsComments for ProjectsIndices at:

http://www.census.gov/hhes/www/housing/housing_patterns/app_b.html

Panel/Longitudinal Study?◦i.e. how something changes over

time?◦Be aware that the actual boundaries

(and the unit ID ) may change between censuses