1. Basics Of Topographic Maps

2. Topographic Maps (Contour Maps or Relief Maps) Two dimensional model of the Earth’s surface that represents 3-D world Show elevation above sea level using contour lines.

3. Contour Map as per top view “Real World” as per vertical profile

4. Contour LineContour Line – - line on a map that connects points of EQUAL elevation. - show elevation and shape of the land Relief – Difference between high and low elevations

5. Contour lines never cross and form closed loops

6. Closely Spaced Contours Steeper Slope (Gradient) – contour lines are closer together.

8. Wide Spaced Contours Gradual/Gentle Slope (Gradient) – contour lines are farther apart.

10. Can show a depression (dip) with hatch marks

11. Map Scales Indicates the distance on the map compared to distance in the real world Graphical - by a line divided into equal parts and marked in units of length.

12. Gradient = height / distance 200 Contour Interval = 20 ft 0246810 miles