Geodemographic Shapefiles

A geographic information system (GIS) project is often comprised of a set of shapefiles. A GIS might include other types of "layers," but a layer based on a shapefile is most common.

This section illustrates use of CV to display various types of layers/shapefiles. In the following views, layers are shown in the legend at the left. In these examples, each map layer corresponds to a shapefile. Point, line, and boundary shapefiles, and their relevancy in school geodemographic analyses, are described below

While some GIS and mapping software do not use shapefiles as the native digital vector map file, shapefiles are the industry standard and most widely used. The Proximity CommunityViewer and related map tools use shapefiles as the native digital vector map file.

Point Shapefile

Example: school point shapefile

Topmost layer in this view

Proximity develops annually updated national scope public and private school shapefiles. Additional information.

The Proximity CommunityViewer software enables any user with the ability to geocode their own address data and create point shapefiles.

Line Shapefile

Example: roads line shapefile

Roads are an integral part of most mapping applications and visually based/geospatial analyses. Often analyses need extensive flexibility regarding what types of roads are displayed, labeled and used. Roads/streets used in this document are variations to the Census Bureau "Edges" MAF/TIGER TIGER/Line shapefiles. The MTAIP updated TIGER/Line shapefiles became available for all states/counties in December 2008.

While high quality streets shapefiles are available from other sources, there are many considerations that make use of road/streets derived from the TIGER/Line edges shapefiles important.

•	Only road/street segments derived from these files are coded so that pertinent geocodes on the left and right side of each street segment can be accessed.

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Only road/street segments derived from these files make it feasible to geocode addresses and accurately assign census block (or higher level aggregate statistical area) codes to an address. Since many addresses may be on a street segment that is a block or census tract boundary, this can be critical.

•	Only road/street segments derived from these files will exactly match boundaries of statistical/political geography such as census blocks (hence anything based upon census blocks), census tracts, places, school districts, congressional districts, to name a few.

•	Roads/streets shapefiles developed by others vary from county to county as to field coverage and definition, date of update, quality, geographic scope of coverage, access and in other ways.

Polygon Shapefile

Example: School district boundary shapefile

Proximity develops annually updated national scope school district shapefiles. Additional information.

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