Topographic map indexes are separated by map series. In the Research Center, the indexes are housed together in the Topographic Indexes Vertical File.
Topographic maps (also called topo maps) are maps that illustrate the lay of the land. With the use of contour lines, these maps effectively depict hills, mountains, plains, and valleys. The United States Geological Survey (USGS), which publishes topographic maps, provides an explanation and history of these maps and information about the map-making process.
Topo maps incorporate features such as contour lines, the magnetic north declination, roads, cities, railroads, pipelines, and fence lines, bodies of water, trees, wells, buildings, and cemeteries. These maps also include the latitude and longitude, and on most topographic series, the township and range. The more detailed series, 1:24,000 and 1:100,000 provide section numbers. The USGS details some of the features found on topographic maps.
In addition to finding out the general lay of the land and the highest and lowest spots in an area, topographic maps can be used for other purposes. Hikers and vacationers often use topos to plan their travels. Students can trace the path of a river, locate national parks, or search for particular landmarks. Genealogists often employ topographs to locate cemeteries, churches and schools.
According to the United States Geological Survey, topographic maps often are used for engineering, energy exploration, natural resource conservation, environmental management, public works design, commercial and residential planning, and outdoor activities like camping, and fishing.
Topographic maps can also help either to establish the legal description of a piece of land or to determine where a piece of property is located by means of a legal description. You can even use them to find out if there are any oil or gas wells on a particular property or to establish where certain pipelines, power lines, or railroads run.
An index to symbols used to read topo maps is available in the Research Center on the map cabinets and duplicate indexes can be found in the 'Maps' vertical file. The USGS provides a list and description of topographic map symbols as well.
To find adjoining maps look for the names of the neighboring maps at the sides and corners of the topo map you are viewing, or look at the chart near the bottom right hand corner that lists the names of the surrounding maps.
Latitude and longitude is located at each corner of a map and at intervals along the map's borders.
Township and Range, when used, are included on the 1:24,000 series, the 1:100,000 series, and the 1:250,000 series. Look along the map borders to find these numbers. Sections are only available on the most detailed maps, the 1:24,000 and 1:100,000 series.
Depending on the scale, section numbers will either be centered in each section or only labeled in the first and last section of each township and range. Each township and range is comprised of thirty-six sections that snake back and forth left to right and right to left rather than being lined up one series of numbers under another.
Contour interval data can be found at the bottom of each map near the scale. Also, look for elevation figures within the contour lines on the map within your selected area. Periodic wider contour lines act as index lines to help determine elevations more easily. Some of the 1:500,000 state topographic maps include bathymetric lines or depth curves in bordering coastal waters.
For more help in reading topographic maps try checking out Reading Topographic Maps: Activities for Earth Science Teachers and Students by James R. Chaplin.
If you would prefer to order your own copy of a map, the map indexes in the Research Center’s Topographic Indexes vertical file can help you determine which map you want, and the USGS has online ordering resources and downloading options.
Ridgway's, Inc. is a local resource for ordering a set of Oklahoma topographic maps on CDs.
7022 E 41st Street, 663-8100
The Research Center has a mapping computer with a variety of products loaded on it. One such product, "All Topo Maps," is a ©2000 CD containing all of the 7 1/2 minute (1:24,000), 1:100,000 scale, and 1:250,000 scale topographic maps for Oklahoma. The viewing software makes it easy to find the map you want by allowing you to search by location, place, or feature name. It even offers measuring tools and keeps track of the current elevation as you mouse over points on the map.
If you are looking for historical Oklahoma topographic maps, the mapping computer also has a collection of historical Oklahoma and Indian Territory Quadrangles loaded. These are 15 or 30 minute maps from the USGS dating generally between the 1900's and the 1940's. This set on DVD was digitized and made available to TCCL by the