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PL321 Software -- Census 2000 P.L. Database Processor
The PL321 software is used to convert Census 2000 P.L. 94-171 dbase file set into a single dbase file. PL321 is an term representing "PL" files "3" to "1".
Important Update: While this software remains available as described below, the functionality of the PL321 software has been integrated into the ASC2DBF software. By using the ASC2DBF software you can bypass a time and space consuming step of first converting the Census ASCII files to dBASE. This section continues to provide a description of the PL321 database generated by either the PL321 or ASC2DBF software. Go to ASC2DBF web page.
The PL321 software builds the "PL321" single file subset version of the original three file P.L. 94-171 data as released by the Census Bureau. The structure and content of the PL321 file is described later in this section.
The PL321 software processes dbase files generated by the program ASC2DBF. You will need to run ASC2DBF before you can use PL321. PL321 and ASC2DBF are both freely available for non-commercial downloading and use. There are no restrictions placed on use or redistribution of data developed using the software.
Features of PL321. The focus of the PL321 is to enable the development of a single table (rather than three connected larger tables) housing all of the most widely used P.L. 94-171 data for a state. PL321 also has the ability to create SQL-like, filtered, subsets of the statewide P.L. files. For example, the data file generated can be restricted to one county, all tracts in a state, census blocks comprising a school district, or selected types of geographic areas of a certain population size. Use extracted data files as "event themes" to display point-oriented population attributes in popular mapping programs (no further conversion required).
PL321 Genesis. ASC2DBF generates three dbase files for the state that you select for processing. To use data contained in these three files, you must use software which can link the three files on the logical record number field (LOGRECNO). This is required since the geographic identifier information (e.g., census tract number) is only in the first of the three dbase records. So, to access data for a particular census tract, you need to be able to locate that census tract code in the first dbase file, associate the tract code with the LOGRECNO in that record, and then locate the record containing the same value for LOGRECNO in dbase files 1 and 2 (referred to as file01 and file02 in the ASC2DBF description). There is an easier, more efficient way, with other attractive by-product results (disk space savings among them!!).
The reason that three dbase files are required for the P.L. 94-171 files is because the maximum number of fields in one dbase record is 255. There are 288 subject matter fields in the P.L. 94-171 files in addition to 80 geographic related codes and fields. These relationships will become more complex as the more detailed summary files are released by Census.
Race/Ethnicity Detail. It turns out that relatively few respondents to the Census 2000 questionnaire identified themselves as being of "two or more races." This percentage varies by geographic area but is typically less than one percent of the population. As a result, the extent of usage of the extended race categories is less widespread that might have otherwise been the case.
A More Usable P.L. 94-171 Subset Database. Warren Glimpse/Proximity has designed a new P.L. 94-171 database record containing the key subject matter fields of most widespread interest. The "PL321 version" contains a record for every geographic entity as contained in the Census version. The record contains all of the original geographic segment fields as contained in the Census version plus 40 subject matter fields (as compared to the 288 fields in the Census version--this is what we eliminated--248 subject matter fields containing the less widely used "N-race" membership details). The 40 subject matter (demographic data) fields are extracted from P.L. Tables 1, 2, 3, and 4 as shown in the table presented below.
| Table PL1 | RACE [71 fields in full record] |
| Universe: Total population | |
| P0010001 | Total |
| P0010002 | Population of one race |
| P0010003 | White alone |
| P0010004 | Black or African American alone |
| P0010005 | American Indian and Alaska Native alone |
| P0010006 | Asian alone |
| P0010007 | Native Hawaiian and Other Pacific Islander alone |
| P0010008 | Some other race alone |
| P0010009 | Population of two or more races |
| Table PL2 | HISPANIC OR LATINO, AND NOT HISPANIC OR LATINO BY RACE [73 fields in full record] |
| Universe: Total population | |
| P0020001 | Total |
| P0020002 | Hispanic or Latino |
| P0020003 | Not Hispanic or Latino |
| P0020004 | Population of one race |
| P0020005 | White alone |
| P0020006 | Black or African American alone |
| P0020007 | American Indian and Alaska Native alone |
| P0020008 | Asian alone |
| P0020009 | Native Hawaiian and Other Pacific Islander alone |
| P0020010 | Some other race alone |
| P0020011 | Population of two or more races |
| Table PL3 | RACE FOR THE POPULATION 18 YEARS AND OVER [71 fields in full record] |
| Universe: Total population 18 years and over | |
| P0030001 | Total |
| P0030002 | Population of one race |
| P0030003 | White alone |
| P0030004 | Black or African American alone |
| P0030005 | American Indian and Alaska Native alone |
| P0030006 | Asian alone |
| P0030007 | Native Hawaiian and Other Pacific Islander alone |
| P0030008 | Some other race alone |
| P0030009 | Population of two or more races |
| Table PL4 | HISPANIC OR LATINO, AND NOT HISPANIC OR LATINO BY RACE FOR THE POPULATION 18 YEARS AND OVER [73 fields in full record] |
| Universe: Total population 18 years and over | |
| P0040001 | Total |
| P0040002 | Hispanic or Latino |
| P0040003 | Not Hispanic or Latino |
| P0040004 | Population of one race |
| P0040005 | White alone |
| P0040006 | Black or African American alone |
| P0040007 | American Indian and Alaska Native alone |
| P0040008 | Asian alone |
| P0040009 | Native Hawaiian and Other Pacific Islander alone |
| P0040010 | Some other race alone |
| P0040011 | Population of two or more races |
The PL321 program processes the three P.L. 94-171 dbase records, selects the appropriate fields to develop the above described single dbase file, and generates that file.
DISCLAIMER OF WARRANTY. The PL321 software made available through this Web site is provided on an "AS IS" basis, without warranty of any kind, including without limitation the warranties of software and/or files being free of defects, merchantable, fit for a particular purpose or non-infringing. The entire risk as to the quality and performance of the software and/or files is borne by you. Should the software or a file be defective in any respect, you alone agree to assume the entire risk and responsibility associated with use of the software and/or file and/or its contents. In addition, the process of acquiring files via the Internet is inherently risky and the entire risk associated with data transfer is borne by you.
Get Started Now! Download the PL321 zip file. Unzip the file into the folder c:\pl (recommended, not required). The downloadable file is set to work immediately with the files that are generated by ASC2DBF.
If you have questions, send e-mail to support@proximityone.com.