Each ".zip" file that you may download from this site contains a suite of files comprising the named data set. These files represent standard ESRI data storage formats - ESRI shape files and ArcInfo coverages. Each data set's specific data storage format is detailed in its descriptive report, accessible on this site by clicking the data set's "title" link.

Consider a typical suite of data called Geodata.zip, for example. This ZIP file of ESRI shape file data would contain the following files:

Geodata.dbf

data table component of shape file

Geodata.shp

graphic data component of shape file

Geodata.shx

3rd essential component of shape file

Geodata.htm

Metadata Report in HTML format

Geodata.txt

Metadata Report in ASCII text, FGDC-encoded for metadata database import

The following optional files may appear, depending on the characteristics of the data set:

Geodata.ddi

Data Dictionary of attributes in ASCII text

Geodata.sbn, .shx, .ain, .aix

Additional shapefile components

readme.txt

Special instructions or cautions about data usage

Some data sets include data in ESRI coverage format. Coverages are made of a pair directories that contain special files storing the geographic information. For the example above we would find:

Geodata

Directory of files that produce the graphic representation of the data

info

Directory of files of attribute data

log

File of transaction history of the coverage in ASCII text