1. Mapping

2. Maps – What Can They Tell Us?
The shape of the land
Direction of water flow in a river or stream
Slope of the land
Weather patterns

3. Maps
All maps have fields, which are regions of space or areas that have a measurable value of a given property.
Isolines – Lines on a field map connecting all points of equal value
Isobars – connect points of equal air pressure
Isotherms – connect points of equal temperature
Contour Lines – connect points of equal elevation

4. Isoline Rules Lines must connect equal points in equal intervals
If there is not a point for a given interval, you must draw the isoline where it would fit.
Isolines must either close or run off the map
Isolines can never touch

5. Practicing Isolines
1. Draw elevation isolines for 40, 50, 60, 70, & 80 feet.
2. What is the approximate elevation of point:
Point A
Point B
Point C
71-79 feet
41-49 feet
51-59 feet
Elevation measured in feet

6. Practicing Isolines What measurable property is shown on this map?
Based on this property, the isolines on this map are called
What is the approximate measurement of this property for New York State?
Temperature
Isotherms
5°C

7. Practicing Isolines – Average Yearly Number of Thunderstorms in the US
Approximately how many thunderstorms occur each year in:
Albany, NY
Los Angeles, CA
New Orleans, LA
20-30
>10
<70

8. Topographic Maps – Maps of an Elevation Field
Topographic Maps show the elevation of the land by using contour lines, and show other natural and man-made features by using symbols.
Contour Lines – isolines on a map connecting points of the same elevation
Elevation – distance (feet) above sea level
Contour Interval – difference in elevation between two consecutive contour lines
Index Contour Line – heavy, dark contour line, usually with numerical value for elevation marked
Depression – special contour lines used to show a hole or crater on Earth’s surface.

9. Depressions

11. What is the contour interval?
What is the highest possible elevation of the hilltop?
Which side of the hill is the steepest?
How do contour lines show a steeper slope?
20 feet
Contour Lines
259 feet
East/right
The contour lines are closer together
Depression Contour
Index Contour

12. River Valleys – The Law of the V’s
Contour lines form a V pattern when crossing streams.
The V always points UPSTREAM

13. Which way is the stream flowing?
Downstream
(Downhill)

14. Drawing Contour Lines on a Field Map – 20, 40 ,60, 80, 100, 120 feet

15. Calculating Gradient
Gradient is the rate at which elevation changes from place to place.
Gradient = change in field value
distance

16. Calculating Gradient
Use the elevation field map that you drew contour lines on to calculate the gradient between:
Point A & C
Gradient = ft
3.5 miles
25.7 ft/mile

17. Point B & D Point B & E Point F & C Gradient = 123 – 13 ft 3 miles

18. Parts of a Map Parts of a Map:
Scale – relates distance on the Earth’s surface and is often given as a ratio.
Map Key – a list of all the symbols used on a map with an explanation of their meaning.
Symbols – pictures used to describe a feature on Earth’s surface.

19. Let’s take a walk up a hill!

20. We’re now at an elevation of 100 meters.

21. Let’s keep going!
100m

22. Now we’re at 200m.
200m
100m

23. Shall we march on?
200m
100m

24. We’ve made it to 300m!
300m
200m
100m

25. On to the peak!
300m
200m
100m

26. We’re on the peak, but what’s our elevation?
300m
200m
100m

27. Any ideas?
Let’s add contour lines for every 50 meters and see if that helps.
300m
200m
100m

28. We know that we are above 350m, but less than 400m.

29. Let’s head down the hill, it’s getting late!
350m
300m
250m
200m
150m
100m
50m

30. Now what’s our elevation?
If you said somewhere between 200m and 250m you are right!
350m
300m
250m
200m
150m
100m
50m

31. Let’s try this again!
350m
300m
250m
200m
150m
100m
50m

32. What’s our elevation now?
If you said 50m or just under, you’re right!
350m
300m
250m
200m
150m
100m
50m

33. Let’s now look at the same hill, but the way we might see it from an airplane!

34. Each color change represents a 50 meter increase.

35. Now, let’s try the same hike! Our elevation is 0 meters.

36. Now what is our elevation?

37. If you said more than 150 meters, but less than 200 meters your right!

38. Let’s go a little higher.

39. Think you know our elevation now?
More than 300 meters
But less than 350 meters

40. If we were standing on the peak, what would be our elevation?
More than 350 meters, less than 400 meters

41. Let’s head down hill.

42. Know our elevation?

43. More than 100 meters,
less than 150 meters

44. I think you got it!

45. Let’s see what you know. E C D B
1200m F
1000m A
800m
400m
600m

46. Quiz Time
Grab a piece of paper and write your answers to the following questions.
Ready?

47. 1. Could the elevation at the peak (B) be 1410 meters?F
No :The elevation must be under 1400 meters, but over 1300 meters.
1000m A
800m
400m
600m

48. 2. What is the elevation at (E)?
400 meters E C D B
1200m F
1000m A
800m
400m
600m

49. 3.What is the elevation difference between (A) and (B)?
1200m F
(A) Is 750 meters, (B) is above 1300 meters. The difference between would be 650 to 700 meters.
1000m A
800m
400m
600m

50. 4. Could the elevation at (F) be 417 meters?
No: It must be more than 700m and less than 800m E C D B
1200m F
1000m A
800m
400m
600m

51. 5. If you walked a straight line from (D) to (C) would you walk over a ridge or down a valley?B
1200m F
1000m A
800m
400m
600m

52. 6.Just looking at the map, would it be easier to head down from the peak going East, or going North?C D B W E
1200m F
1000m A
800m
400m
600m S

53. Answer!
6. East: When contour lines are close together that means there is a steep slope, the further apart the lines, the more gentile the slope and therefore an easier walk! Go east!