Census Bureau

Census 2000 Summary File 1 (SF1)

FTP ASCII text data files

Contents

Uncompress ASCII text data files        

Which data files do you need to download?        

Technical information

Uncompress ASCII text data files

The data files from the census FTP site contain a line feed character only at the end of each record. For successful use with many programs running in a Windows environment, these files need to be modified to use the ASCII carriage return/line feed sequence, chr(13) + chr(10), as a record terminator. This is an easy step in the UnZIP process using any UnZIP software which offers a conversion option. We tested PKZIP for Windows, version 4.00 following the steps outlined below. This PKZIP shareware can be downloaded from pkware.com. After installing PKZIP, perform the following steps:

Select the file
Select the Extract option on the tool bar
Select the Options button at the bottom of the Extract page
Under the Miscellaneous section, select "DOS - convert to CR/LF"

Which data file(s) do you need to download?

All geographic area identifiers (area names and codes, ...) are in the geography file only. This file must be downloaded in order to identify the area being tabulated in the data files. See chapter 3: Subject Locator to identify tables of interest and then Chapter 2: How to Use This File to identify the data file(s) that contain these tables from the technical documentation.

Technical information

An SF1 data set consists of one geographic file and thirty nine data files. The geographic file has a fixed record length of 400 characters and is not field (or column) delimited. Each of the thirty nine data files are comma field delimited with variable record lengths. None of the ASCII text files contain header records (a first record with fieldnames).

The only relationship between any one file (geographic or data) and another is the field LOGRECNO (logical record number). This field is a unique key.

There is a one-to-one correspondence based on LOGRECNO between the geographic file and data files 01-11 and 37-39 only. Data files 12-36 contain only PCT tables. PCT tables contain data down to the census tract level only.

Imagine the geographic file and any or all of the thirty nine data files laid side by side or a very wide dataset sliced vertically. The data set was split into multiple files due to a limit in the number of fields allowed per record in most popular database and spreadsheet programs.

Electronic Products Development Branch
Administrative and Customer Services Division
U.S. Census Bureau

Last Updated: Wednesday, 26-Sep-2001 11:13:52 EDT