System Requirements for Viewing GIS Data Layers
Use of downloaded shapefiles and feature classes will require an ESRI geographic information system (GIS) software product or CAD software that is capable of reading shapefiles and feature classes. ESRI products are available at www.esri.com.
If you do not own ESRI or CAD software, and you need to access the resident shapefile or feature class data, then ESRI provides ArcGIS Explorer, a free viewer designed for basic data viewing and query. Download GIS shapefiles or feature classes, and the ArcGIS Explorer software.