A topographic map is a map that shows the shape (topography)of the land.

Topographic Map Vocabulary Each contour line represents lines of equal elevation The space between contour lines is called the contour interval Every fifth line is called an index contour with the number of feet of elevation Little lines that intersect contour lines are called “hachures”

Rules for Topographic Maps Two contour lines never cross each other Contours make a “V” shape as they cross streams, “v’s” point upstream The closer the contour lines are, the steeper the slope is Closed contours (circles inside each other) represent hills All contour lines close eventually even if it’s off the map Hachure marks represent depressions

Finding the map’s location on Earth Latitude –horizontal lines show distance north or south from equator Longitude – vertical lines show distance east or west from prime meridian Together, they form a grid of Earth’s surface

How latitude/longitude is divided Latitude –horizontal lines show distance north or south from equator Divided into degrees, minutes, seconds 1 degree = 60 minutes 1 minute = 60 seconds ex. N 45° 30’ 30” Longitude – vertical lines show distance east or west from prime meridian Degrees, minutes, seconds like latitude ex. W 124° 30’ 45”

Map Scales Verbal – scale is stated with sentence ex. 1 inch=4 miles Graphic- image on map Fractional- can be any unit ex. 1:24,000 means: every cm on map equals 24,000 cms in actual distance OR 2. every inch on map equals 24,000 inches in actual distance

Gradient of a river or slope (how steep it is) Difference in elevation (rise) divided by Distance on map (run) written as ft/mi Example: the Willamette River is 410 ft elevation at its head and 10 ft at its mouth. It flows apprx. 100 miles. What is its gradient? 410 ft -10 ft =400 ft 400 ft ÷100 mi = 4 ft/mi

Using the Metric System The METER is the basic unit for length 1/1000 m = 1 mm 1/100 m = 1 cm 1/10m = decimeter Meter 1m x 10=decameter 1m x 100 = hectometer 1 m x 1000 = kilometer To convert from cm to km, just move the decimal point 5 places to the left 453,200 cm = 4.5 km