How do I use the shapefiles?
A shapefile is a proprietary file format of ESRI. Shapefiles have de facto become a standard for the storage of vector geometry information and associated attribute information to be used in desktop GIS applications. This file format is composed by a minimum of three files, a .shp .shx and .dbf files which need to be kept together in the same directory for the file to be opened by GIS software. A shapefile can be opened and visualized by the vast majority of GIS software, including ESRI ArcGIS and free and open source software such as Quantum GIS (www.qgis.