USGS QUAD

If you’ve read Mastering AutoCAD Civil 3D 2009, you know page 127 contains a reference to the GIS data links I’ve posted on the original “Civil 3D – Paving the Way.” While that site remains live, it is no longer updated (click here to update your feeds). But in keeping with tradition, I’m continuing to build a one-stop shop for finding all things GIS here (look for Geospatial Links to the right). Using the AutoCAD MAP 3D interface built into AutoCAD Civil 3D, digital data from various coordinate systems can easily be transformed between systems and incorporated into your drawings – no scaling or rotating required. The most commonly downloaded digital map is the USGS QUAD.

The USGS QUAD or Quadrangle
The USGS took over responsibility for mapping the country in 1879 and has been the primary civilian mapping agency of the United States ever since. The best known USGS maps are the 1:24,000-scale topographic maps, also known as 7.5-minute quadrangles (they measure 7.5 minutes of longitude x 7.5 minutes of latitude, a.k.a. a 1 degree block as discussed in an earlier post), or simply QUADs. More than 55,000 7.5-minute maps were made to cover the 48 conterminous States. This is the only uniform map series that covers the entire area of the United States in considerable detail.

USGS topographic quadrangle maps are marked with grid lines and tics around the map collar which make it possible to identify locations on the map by several methods, including the graticule measurements of longitude and latitude, the township and section method within the Public Land Survey System, and cartesian coordinates in both the State Plane Coordinate System and the Universal Transverse Mercator coordinate system.

In recent years, budget constraints have forced the USGS to rely on donations of time by civilian volunteers in an attempt to update its 7.5-minute topographic map series, but the series was officially completed in 1992. In 2000, the USGS stated outright that the program was to be phased out in favor of their National Map (not to be confused with the National Atlas of the United States produced by the Department of the Interior, one of whose bureaus is USGS).

All topographic maps from the 7.5-minute program, as well as various derived products, remain available for sale or download.

For a list of agencies offering free or lost cost data, browse to the University of Arkansas Libraries. The University also offers links for International GIS Data.

Civil 3D Tutorials*
Register Today to access to our comprehensive library of Civil 3D Tutorials for as low as $20.

*Access to the Library is a free service to our clients.