10-15-2001 La Porte Redisticting Committee Regular Meeting

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0 Citv of La Porte L� Interoffice Memorandum To: Doug Kneupper From: ff Litchfield Date: ( ctober 9, 2001 Subject: Method used to provide Census Information for Redistricting Effort The Census Bureau released the detailed information for Texas on August 22, 2001. The information was available over the Internet. The steps necessary to get the information are as follows: Log onto www.census.gov Click on the second item on the page, which is "Detailed Tables (SF1) data Click on Texas Click on Texas At this point, you will have a choice to download several files. The Census Data is broken into 40 different files. The information needed for your report came from the txgeo.ufl.zip and the tx00001.ufl.zip files. These files are zipped files and are rather large. I downloaded the files to my PC and unzipped them. The files unzip to dBase files. Fortunately, I am proficient in dBase, having used it for the last 19 years. The txgeo file contains the track and block information as well as the housing units and the total population. The information for La Porte is keyed to this file. The file also contains a logical record number which ties it to the other 39 files. The breakdown by race came from the tx00001 file and ties back to the txgeo file by the logical record number. Once I extracted the data from both files, I found there were 798 different census blocks in La Porte. I also found 243 of them had a population of 0. However, three of the blocks with 0 population had housing units. In order to cut down on the work required to report the population by proposed district, I deleted the 240 blocks with 0 population and 0 housing units. (Note — for quality control purposes, I prepared a spreadsheet with all 798 blocks. I have attached it to this memo.) The file with the remaining 558 different census blocks was converted to an excel file which was then coded by the proposed La Porte council district. This was done by manually reviewing the proposed council boundary lines drawn on the redistricting map and entering the district number into the file. In order to match the records, you have to match both the census tract and block numbers. Once the data was matched, a spreadsheet was prepared that summarized the information by proposed council district.