1. Topographic Maps

2. Topography -
refers to the shape of the land

3. - a bird’s eye view of land that shows changes in elevation
Topographic Map

4. - are lines that connect points of equal elevation
Contour Lines
- are lines that connect points of equal elevation
Change in 10 ft
Contour interval
- is the change in elevation between two consecutive contour lines

5. Hachured contour lines
- represent a depression in the land

6. Ex: - measures how steep a slope is Gradient Formula
gradient = the change in elevation between 2 points
the distance between those 2 points
Ex:
𝒈= 𝟏𝟎𝟎 𝒇𝒕−𝟓𝟎 𝒇𝒕 𝟐 𝒎𝒊𝒍𝒆𝒔
𝒈= 𝟓𝟎 𝒇𝒕 𝟐 𝒎𝒊𝒍𝒆𝒔
𝒈= 𝟐𝟓 𝒇𝒕 𝒎𝒊𝒍𝒆

7. Practice Gradient Problems
Point A has an elevation of 285 ft and point B which is 14.5 miles away has an elevation of 410 ft. What is the gradient between point A and B?
𝒈= 𝑪𝒉𝒂𝒏𝒈𝒆 𝒊𝒏 𝑬𝒍𝒆𝒗𝒂𝒕𝒊𝒐𝒏 𝑫𝒊𝒔𝒕𝒂𝒏𝒄𝒆
𝒈= 𝟒𝟏𝟎 𝒇𝒕−𝟐𝟖𝟓 𝒇𝒕 𝟏𝟒.𝟓 𝒎𝒊𝒍𝒆𝒔
𝒈= 125 ft 14.5 𝒎𝒊𝒍𝒆𝒔
𝒈=8.6 𝒇𝒕 𝒎𝒊𝒍𝒆

8. 𝒈= 𝑪𝒉𝒂𝒏𝒈𝒆 𝒊𝒏 𝑬𝒍𝒆𝒗𝒂𝒕𝒊𝒐𝒏 𝑫𝒊𝒔𝒕𝒂𝒏𝒄𝒆
𝒈= 𝟏𝟐𝟎 𝒇𝒕−𝟗𝟎𝒇𝒕 𝟑 𝒎𝒊𝒍𝒆𝒔
𝒈= 𝟑𝟎𝒇𝒕 𝟑 𝒎𝒊𝒍𝒆𝒔
𝒈=10 𝒇𝒕 𝒎𝒊𝒍𝒆
Assuming points X and Y are 3 miles apart, what is the gradient for line XY?

9. Profile
- the side view of something (in this case land)

10. Rules for Topographic Maps
Contour lines do not cross each other or other contour lines.
The closer the contour lines are to each other the steeper the land.

12. 3. Hills/Mountains are shown as “circles” on topographic maps.

13. 4. Contour lines that cross a stream/river valley make a “V” which points upstream.