July 9, 2013

Learn How To Read USGS Topographical Maps

USGS topographical maps are available on the Internet and can be copied or they can be purchased at the USGS Internet store. These maps are put out by the U. S. Geological Survey Agency and depict areas of the earth, showing both horizontal and vertical positions of the terrain. They are the result of many years of work by USGS and a number of other government agencies.


Usgs Topographical Maps

The word topographical comes from with the Greek language with ‘topo’ meaning a place and ‘graphien’ meaning to write. This has combined into a word meaning a written, drawn and description of a location which what is done with the maps used today. These maps are very specific in their presentation of the earth’s surface.

Topographical maps are not something that is new. Archaeologists have found Roman maps that were drawn between a 335-366 A. D. These early maps showed topographical features of roads, mountains, cities and rivers but were confined to small areas and subject to errors. Today’s maps began in 1807 with a survey of the Atlantic coastline and expanded as time went on. Today they there are over 56,000 of these maps of the United States.

Topographical maps are constructed based on the shape of the earth and have what is known as as contour lines. The lines are used to measure heights, depths and other features of the earth’s surface, making it possible to establish what is above or below a certain point, such as sea level. They are able to accurately pinpoint exact features of different locations.

These maps are made up of colored lines and symbols which indicate such things as mountains, rivers, streams, railroads, trails, buildings and other things. Features are shown as points, lines, or areas depending on what is being portrayed. There are many different maps showing various features of the same area.

The many colors used in these maps have specific meanings. For example, water is blue, vegetation is green, red represents important roads, black represents boundaries and other such features, and so forth. Each item is clearly marked and identified so it is not difficult to find what one is looking for.

The maps also show elevations of the land meaning whether it is mountainous, flat and above or below sea level. It will also show steep slopes and general shape and of all the terrain. By using the scales and explanations that come with each map presented, they are simple to read. The colors used are consistent throughout which is of great help when interpreting their meanings.

With the many maps that are available in this subject it is simple for anyone to locate information they are seeking. Through the great work that has been carried on by the USGS special effort has been made to clearly indicate the different features of the earth. This information has helped tremendously in many areas of exploration for things such as gas, oil and other things that are often determined by the contour of the earth. Learning about the earth is an exciting adventure that can be enjoyed by everyone. Reading these maps will show how the earth is formed, where water resources are as well as other features that make up the world people live in.

Find more information,visit http://store.usgs.gov/