Block Assignment Files - District plans are ultimately defined in terms of census tabulation blocks, the smallest unit of geography for which population is reported. The Census Bureau demarcated 232,403 blocks for North Carolina in the 2000 census. Block assignment files are comma-separated value files (see below), each line consisting of a block key followed by a district number. The block key is a concatenation of codes in the form state(2) + county(3) + tract(4.2) + block(4). The block key "371830605012056", would be interpreted as state ="37", county ="183", tract ="0605.01", block ="2056". Blocks are as defined in the Census Bureau's Redistricting 2000 TIGER/Line Files.
CSV - or "comma separated value" format is a simple text format consisting of values separated by commas. It is easily imported into spreadsheet and database programs, with each line of the file corresponding to a table row, and each item in a line corresponding to a table column. It can also be viewed with text editor programs such as NotePad or WordPad.
PDF - Portable Document Format, created by Adobe. These files can be viewed with Adobe's freely distributed Acrobat Reader. With a PDF file a person can zoom and pan over what is essentially a digital version of a paper map. The format also works well for printing.
Shapefile - This is a spatial data format created by ESRI. Each 'shapefile' actually consists of several files. These files can be used with geographic information system software. ESRI offers a freely downloadable application called ArcExplorer that can be used to view shapefiles.
ZIP - Due to large size, the 'Shape' and delimited text files linked from this site have been compressed or "zipped". Two popular programs that you can use to decompress them are WinZip and PKZip.
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