A New Way to Look at the World Topographic Maps

Here is a picture of a landform, how could you show the features of this 3-d landform on a 2-d sheet of paper?

What is a topographic map A map that represents the 3-d configuration of land using lines and symbols They show the shape and location of mountains, valleys, streams, roads, buildings, wooded areas, and many other features A topographic map shows the elevation of the land surface, below, at, or above sea level

Why use a topographic map? They are used in city development, to plan parks, neighborhoods, buildings, roads, pipeline and power line routes and recreational activities such as hiking, boating, camping and hunting Topographic maps help to give you the lay of the land

What is topography? The configuration of the land surface Shown on topographic maps with contour lines (imaginary lines on the earth’s surface of equal value) If you walk around a contour line your elevation DOES NOT CHANGE

Where water meets the land is sea level, or zero, and walking around the shore your elevation will not change and you will be following a contour line.

If you stray from the shoreline and start walking down into the ocean, the elevation of the ground is negative.

If instead, you walk up the beach, your elevation will be higher and you will be above sea level.

Rules for creating a topographic map Each contour line represents one elevation Contour lines never touch or cross (except in the case of a vertical cliff) The contour interval is the spacing between the contour lines, usually 10, 15, 20, 25, 50, or 100 feet Contour lines close together mean a steeper slope Contour lines farther apart mean a gentler slope

Scale Just like any other map, topographic maps have a scale, it shows the relationship between the distance on the map and the distance on the ground The scale will be given in the key, so will the contour interval

Making a topographic map The first line marks sea level (or 0 ft.)

Now imagine that sea level has risen 10 ft, the new map shows the new coastline

Sea level has risen another 10 feet, so 20 feet from the beginning

Sea level has risen another 10 ft., a total of 30 ft.

Now if we combine all of those pictures, here’s what we get!

How to read a topographic map If a point is on the contour line, then that location is that exact elevation If a point is in between contour lines, you have to use your judgment to judge the elevation Contour lines close together mean a steeper slope Contour lines farther apart mean a gentler slope

Elevation of Point A Since point A is on the 0 ft. contour line, it has an elevation of 0 ft

Elevation of Point B Since point B is on the 10 ft. contour line, it has an elevation of 10 ft

Elevation of Point C Point C is in between the 10 and 20 ft contour lines, that means its elevation is somewhere between 10 and 20 feet A good estimate would be 14-16 ft

Elevation of Point D Point D is inside the 20 ft contour line, and there is no 30 ft contour line, it is somewhere between 20 ft and 30 ft A good guess would be 22 ft

Elevation of Point E Point E is between the 0 ft and 10 ft contour line It is closer to the 10 ft contour line, so its elevation would be 8 ft

Where would you want to build a hotel on the island?

Now look how these landforms match up with their topographic maps

Look at these other topographic maps

Resources Used http://facstaff.gpc.edu/~pgore/Earth&Space/t opomaps.html http://msnucleus.org/membership/html/k- 6/uc/geography/5/ucg5_1a.html