RE: [CTPP] How to use the Census Redistricting Summary File in Access

Since I have seen a lot questions about this I thought I would post my personal notes. If your state hasn't come out yet I strongly suggest downloading a different state and practicing. Once you get the method down, it will be easy to repeat. These instructions are for Access 2003 but I think they are similar for Access 2007. You will need the following documents. Download them to your computer and keep them close at all times. 0FILE_STRUCTURE.pdf found at http://www2.census.gov/census_2010/01-Redistricting_File--PL_94-171/0FILE_ST RUCTURE.pdf 0GEOID_Construction_for_Matching.pdf found at http://www2.census.gov/census_2010/01-Redistricting_File--PL_94-171/0GEOID_C onstruction_for_Matching.pdf pl94-171_tech_doc.pdf found at http://www.census.gov/prod/cen2010/doc/pl94-171.pdf 1. Go to http://www2.census.gov/census_2010/01-Redistricting_File--PL_94-171/ and download the access document that matches your MS Access version, either PL2010_Access.accdb or PL2010_Access2003.mdb. 2. In the same directory, go to the folder your state is in and download everything in the folder. 3. Unzip the files. 4. Open the PDF called 0FILE_STRUCTURE.pdf. Read the first page, it has useful information. The go to the section marked "For Access Users" on page 2. FOLLOW THESE INSTRUCTIONS EXACTLY. 5. After the tables are imported into Access, you should have the two data tables and the geography table automatically joined by the LOGRECNO field. on the topics of your choice. Start a new query in design view. I recommend starting all queries by adding the entire geography table until you get a feel for which fields you don't need. 6. SUMLEV is the field that will let you extract a particular geography, such as tracts or counties. You can find a full listing of SUMLEVs under Chapter 4 of pl94-171_tech_doc.pdf. So if you want a table that has all the census tracts in your state, type "140" under the Criteria field of the SUMLEV column in your query design. 7. The other two tables list your data fields. The table names are given in the back of 0FILE_STRUCTURE.pdf. 8. Export the query to the format of your choice - Excel, dbf, txt, ect. Note that only the newest Excel program will handle more than 65,000 columns. 9. If you are using the data in GIS, you will need to construct a GEOID field to match the one in the shapefile. The file 0GEOID_Construction_for_Matching.pdf provides formulas for doing this. Concatenate the fields found in the geography half of your exported table into a GEOID field. 10. Analyze! Analyze! Analyze! TIP: Compare the number of records in your shapefile with the numbers of records in your exported table to make sure the table was extracted correctly. Hopefully these steps make things less confusing, not more. Good luck! Mara Mara Kaminowitz GIS Analyst ......................................................................... Baltimore Metropolitan Council Offices at McHenry Row 1500 Whetstone Way Suite 300 Baltimore, MD 21230 410-732-0500 ext. 1030 <mailto:mkaminowitz@baltometro.org> mkaminowitz(a)baltometro.org <http://www.baltometro.org/> www.baltometro.org _____ Confidentiality Statement This message may contain legally privileged and confidential information that is intended only for the use of the recipient(s) named above. If you are not an intended recipient, taking any action based on the contents of this message is strictly prohibited. Please immediately notify the sender if you have received this message in error. ------------------------------------------------------------------------ _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news