1. Topographic Map Notes FIELD- Area where a value is measured.
ISOLINES- a line connecting points of equal value.

2. Examples of isolines: (The weather channel loves isolines!)
Isotherms: points of equal temperature
Isobar: points of equal barometric (air) pressure
Contour Lines: points of equal elevation
Isohyet: Points of equal rainfall
Anything else you can get a value for.
(The weather channel loves isolines!)

6. What is the purpose?

7. When might someone
use a topographic
map?
building homes
plan a hiking trip
landscaping
road building

8. Rules for Drawing Isolines:
1. All points on the line MUST have the same value 5 5
10
10
10
10
15
15

9. 2. Isolines are gentle, curving lines- no sharp corners.5 5
10
10
10
10
15
15

10. 3. Isolines are always closed curves even though the map might only show part of it.

11. 4. Isolines NEVER cross- this would mean that one point has two different values.
60 °
50 °
40 °
30 ° X
20° Z Y

12. 5. Isolines usually have a parallel trend

13. 6. The interval between 2 isolines must stay constant30 40 50 60

14. Contour Interval? 25

15. 6. We can infer any value that exists between 2 lines20 *X *Z *Y 30

16. Contour
Interval? 20
Elevation of "A"?
540
Elevation of "B"?
580

17. 619

18. 8. Index Contour Lines
Every 4th or 5th contour line is thicker and bolder and the elevation is shown on the line

19. 9. Depression contour lines show areas where land sinks down-represented by…
Hachured
contour lines

20. concerning hachured lines?
What are the rules
concerning hachured lines?
first hachured
line has same
elevation as previous
contour line

21. 10. Rivers / Streams
When a contour line crosses a river or stream they bend upstream
Towards where the water comes from!!

22. top of the page, what direction
If north is at the
top of the page, what direction
is this river flowing?
south

23. Can a river flow north?
yes!

24. All rivers and streams must flow
DOWNHILL

26. 11. Gradient shows how quickly the value changes from one point to another.
How STEEP the hill or mountain is
A steep (high) gradient- lines are close together.
A gentle (low) gradient - lines are far apart.
Gentle area
Steep area

27. Gradient can be calculated using the formula

28. What is the distance, in kilometers, from Kingston to Oswego?
TAKE OUT YOUR ESRT’s!!
What is the distance, in kilometers, from Kingston to Oswego?
266 km
What is the distance, in miles, from Plattsburgh to Jamestown?
342 miles

29. gradient = change in elevation distance
The elevation of Albany is 282 feet.
The elevation at Binghamton is 1634 feet.
Calculate the gradient to the nearest tenth of a ft/mi. Show all work.
gradient = change in elevation
distance =
115 miles
= 1352 ft
115 miles
= 11.8 ft/mile

30. gradient = change in elevation distance
The elevation of Watertown is 99m.
The elevation at Oswego is 144m.
Calculate the gradient to the nearest tenth of a m/km. Show all work.
gradient = change in elevation
distance =
75 km
= 45 m
75 km
= 0.6 m/km

31. gradient = change in temperature distance
If the distance between
the two
circled cities is 425 km,
calculate the temperature
gradient to the nearest hundredth?
Show all work.
gradient = change in temperature
distance
= 82-48
425
= 34
425
= °F/km

32. Practice drawing isolines

33. Highlight all the data points with the same value.

34. Fill in gaps in data.

35. Connect the dots.

36. Go on to the next value.

37. Now try Practice 2!!!!!

40. Topographic Profiles
Profiles show the side view of the land

41. Please match the contour map on the left with the profile on the right.

42. What are the steps to draw a topographic profile
place a piece of SCRAP paper between the 2 points
MARK where every contour line
touches the edge of the paper
determine the elevation of each mark
place the paper on the graph and PLOT the elevation of each contour line