Digital Maps

Digital Maps

Digital maps are electronic files of maps. They can only be viewed if you have the proper software to do so*. We use ESRI's ArcGIS Geographic Information System (GIS) Software and Bentley's Microstation Computer Aided Drafting and Design (CADD) software to create our digital maps.

GIS Data
Our comprehensive list of geospatial data is available on-line in our GeoSpatial Data Catalog. Our GIS data is in ESRI's shapefile and coverage formats.

CADD Data and TIFF files
CADD data is available in Microstation's DGN format from our FTP site. We also have TIFF images of some of our maps, but beware they can take a long time to download depending on your Internet connection.

FTP Site Information (dgn/tif)

Our CADD files were digitized from the USGS quadrangles over a period of 15 years. We update the State, US, and Interstate Highways every year. Non-state owned roads and streets, railroads, airports and other features on the maps are updated at irregular intervals and may be out-of-date.

Each file represents a 30 x 60 minute quadrangle (32 7.5 minute quadrangles) which was digitized at a scale of 1:24,000 (1 inch to 2,000 feet).

Use the map below to help you choose which files to download.

• Move your mouse over the area you are interested in;
• Click on the left mouse button to down load that file.

Or...go directly to the FTP site to choose the files you'd like to download.

The file names match the codes on the map. The code 0416T references a geographic area in the state.

Or... use a Larger Version of the Quad Index Map.

There are several files on the ftp site that will help you to use our CADD files. The first two are available as Microsoft Windows 2000 Word (.doc) files or MSDOS (.txt) text files. The 00tindex.dgn is a design file of the above map.

• CADD Mapping Parameters
• Level Structure - 24K Quads
• 00tindex.dgn

For further information about our CADD files, please contact us directly. Not all files are available from the ftp site. We also have some very nice TIFF images of maps on the ftp site.

WARNING: Many of the files on the ftp site are between 1 MB - 5 MB. Some of the TIFF files are much larger (12 MB). Depending on your connection, it could take a long time to download a file.

Some of the files have been compressed into zipped files. Whenever possible, download files with the extension .zip. Once downloaded they can be unzipped with Winzip.

Download WinZip 

*You may be able to read shapefile and DGN formats using other software so please refer to your software manuals. For example ESRI's ArcView GIS software can read the DGN format with some limitations.

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