Topographic Maps Knowledge of Maps What are they? What are they used for? Why are they important?

Topographic Maps Knowledge of Maps What are they? What are they used for? Why are they important?

Topographic Maps Maps that show the change in elevation of land. Elevation is the height of land above the level of the sea. Elevation is shown by contour lines.

Contour Lines Lines on a map that connect points of equal elevation Every point on a contour line has the same elevation. Contour lines NEVER touch.

Imagine it this way. Rising water and Spray Paint! Every time the water rose, we painted the level of the water. We also plotted the elevation of the water. When the water receded, we were left with the paint rings. We just created contour lines. Everywhere on the line is equal in elevation. Look down from above to visualize a topographic map.

Where the lines Come From Topographic Map (as seen from above) Actual Land

Index Contours The darker, thicker contour lines are called: INDEX CONTOURS Typically every 5 th line on a Topo map is an index contour.

Topographic Profile Helps us to see the actual shape of land. Follow these simple steps to draw a profile: 5 10 15 20 25 25 20 15 10 5

Contour Intervals The word interval means THE DIFFERENCE BETWEEN. When you go from contour line to another the elevation changes. The difference in elevation from one line to another is called the CONTOUR INTERVAL. Find an index contour. Find an index contour the is right BELOW the one you just found. Subtract the two index contours. Divide that number by 5 (or the number of contour lines between the two index contours).

Contour Intervals 100 100 50 50 50 50 5 = 10 0

Rivers and Streams Shown by V-shaped contour lines. V s point in the direction water is COMING FROM. Water always moves from up high to down low (higher contours to lower contours). NORTH SOUTH

North South

Shape of the Land What do we notice about the shape of the land and the arrangement of contours? 5 10 15 20 25

Steep and Gentle Slopes STEEP SLOPES: Contour lines are close together. GENTLE SLOPES: Contour lines are far apart. 25 5 10 15 20 25 5 5

Hills and Basins Shown by closed-circles o A hill: land that raises up-hill. o A hill: land that raises up-hill. When you see hachure marks you re looking at a depression. Example: A VOLCANO!!!

Hills and Basins 40 10

Hills and Basins 100 400

Hills and Basins 100 400

Topographic Maps Reading in-between the lines 100 50 0 What is the elevation at point A? = 20 What is the elevation at point B? = 90

Topographic Maps Reading in-between the lines 100 50 100 What would the terrain look like if you were to walk from point A to point B? Down hill, then up hill.

Topographic Maps Reading in-between the lines 100 50 0 What would the terrain look like if you were to walk from point A to point B? Up hill.

Map Scales Map Scales o Maps are not LIFE-SIZE. o A scale converts the size of something on a map to its actual size in real life. A ratio, such as 1:80,000 (spoken as 1 to 80,000) means: That for 1 unit on a map = 80,000 units in real life. Map Scale: 1: 80,000 = 1 inch Map Scale: 1: 80,000 Example: Look at the map below. o The scale is 1:80,000 o I measure a distance of 1 inch between both rivers. o But in real life, the rivers are:? 100 50 100 So, If a map scale is, for example, 1:45,000. Then: 1 cm = cm 1 paper clip = paper clips 1 ft = ft. 0