Converting downloaded GIS data

You may need to unzip or untar the files you download. Most files available for download are stored in a compressed format so that they take up less space on the server and download faster.You should be able to decompress them using one of the readily available tools such as PkZip or Winzip. To make things easier, turn off the Save Folder Information (or whatever it's called in your software) option

If the file is in ArcInfo exchange format, e00, you will need to use the Import71 utility. This will convert the files into a format readable by your GIS software. The main difference (for your purposes) between ArcInfo format and Shapefile format is that ArcInfo uses an extra folder called Info to store information about the coverages.

All coverages at a certain hierarchical level in the directory (or folder) structure put administrative files in the Info folder. This means that you can't just copy a coverage from one place to another using the Explorer!

Other data exchange formats are out there, for which you will need other tools. These include SDTS, DLG and DEM.

More details in class...