The distinctive characteristic of a topographic map is the use of elevation contour lines to show the shape of the Earth’s surface. USGS topographic maps also show many other kinds of geographic features including roads, railroads, rivers, streams, lakes, boundaries, place or feature names, mountains, and much more.

A topographical map is one that shows the physical features of the land. Besides just showing landforms such as mountains and rivers, the map also shows the elevation changes of the land. Elevation is shown using contour lines. When a contour line is drawn on a map it represents a given elevation.

Topography is the study of the forms and features of land surfaces. The topography of an area could refer to the surface forms and features themselves, or a description (especially their depiction in maps).

Topographic maps are an important tool because they can represent the three-dimensional landscape in two dimensions. A person who can read a topo map can find out the location of peaks, valleys, ridges and saddles, among other land features.

Who uses topography maps? Hikers, campers, snow skiers, city and county planners, the Fish and Wildlife Service, Forest Service, miners, loggers, highway planners and construction workers, travelers, surveyors, geologists, engineers, and scientists are just a few of the people who use topographic maps.

Several principles are important for reading a topographic map:

1. Contour lines show the 3-dimensional shape of the land (Figure below).
2. Concentric circles indicate a hill.
3. Hatched concentric circles indicate a depression, as seen in the Figure below.
4. V-shaped expanses of contour lines indicate stream valleys.

Topographic Mapping Elements for Digital Map Products

• contour lines.
• contour related text.
• spot elevations.
• spot elevation related text.

A geologic map shows the distribution of materials at or near the Earth’s surface. Rock types or unconsolidated materials are generally grouped into map units and depicted using different colors. Geologic maps show information collected manually in the field by walking Vermont’s landscape.

Faults and folds are also shown on geologic maps. The geology is superimposed on a topographic map to give a more complete view of the geology of the region. A geologic map shows mappable rock units, mappable sediment units that cover up the rocks, and geologic structures such as faults and folds.

A contour line is a line drawn on a topographic map to indicate ground elevation or depression. A contour interval is the vertical distance or difference in elevation between contour lines. If the numbers associated with specific contour lines are increasing, the elevation of the terrain is also increasing.

Geologic maps are two dimensional (2D) representations of geologic formations and structures at the Earth’s surface, including formations, faults, folds, inclined strata, and rock types. Geologists use geologic maps to represent where geologic formations, faults, folds, and inclined rock units are.

In what SIX ways are geologic maps useful?

• observing geologic structures.
• mineral identification and exploration.
• disaster management.
• elevations and contour maps.
• plate movements.
• list of rock types with aerial distribution.

The steps of geological mapping activity are:

1. Make outcrop observation, and make a description of it.
2. Measure the position of rocks (strike and dip), geological structure elements, and other geological elements.
3. Make a record observations in a field notebook.
4. Determine the outcrop location by using GPS.

By knowing more about the geologic history of our area, you can better understand the type of rocks that are in your own backyard and why they are there. We will look at the history of the Midwest as it unfolds: as a series of major events over the past one billion years that created and shaped the area.

There are peaks, valleys, jagged edges, rolling hills, and everything in between. In general, we call these geological features, but this term is very broad and refers to any of the physical features on Earth’s surface. You might also hear them referred to as landscapes, topography, and landforms.