1. Topographical Mapping IGSS

2. Maps ► There are too many different types of maps to mention here. ► Scientists tend to use the same variety of maps to see types of rock, air pressure, varying depths of groundwater in a region. ► A topographic map shows surface features, called topography.

3. Maps ► These features can be natural:  Rivers  Hills  Caverns  Mountains ► These features can be man-made:  Buildings  Roads

4. Maps ► A topographic map shows the elevation above the mean sea level. ► The mean sea level is the midway point between high and low tide. ► A topographic map provides great detail about the surface of an area by showing the size, shape and elevation of an area.

5. Maps ► Contour lines show elevation. ► Contour lines are isograms: A single line represents a single elevation. ► The contour interval is the difference in elevation between contour lines. ► The contour interval for the picture is:_______

6. Maps ► Index contours are the lines that have the elevation labeled and are usually every 5 th line. They are in bold. ► Topographic maps will also show the relief: the difference in elevation between the highest and the lowest point on the map.

7. Maps ► Reading a topographical map.  Contour lines that are spaced far apart represent a very gradual rise in the land.  Closely spaced contour lines represent a very steep slope.  V shaped contour lines represent a valley with the V pointing toward the higher end of the valley.  The V will also point upstream if there is a river flowing through the valley.

8. Maps ► Closed looped contour lines represent a hill. ► Closed looped contour lines with short lines perpendicular to the loop represent a depression.

9. Maps Map symbols Color Buildings, boundaries, roads, railroads Black Major highways Red Bodies of water Blue Forested areas Green Contour lines Brown or Black Anything updated by aerial observation only. Purple