## NY,NY 3 years ago Need help with drawing in the contour lines on a map. The contour interval is 5 m.

1. NY,NY

There's just a bunch of numbers and it says to draw in the contour lines.

2. timo86m

3. timo86m

of the problem

4. NY,NY

5. NY,NY

its super ugly i know.... :/

6. NY,NY

#14

7. timo86m

Contour interval is the actual change in elevation represented by the space between two adjacent topographic "rings". For example, if there is a contour interval of 20 feet, each topographic line on the map represents going either up or down by 20 feet of elevation (and sometimes it's hard to tell which). For convenience, many mapmakers include numbers every four or five lines to tell you what elevation is represented by that line.

8. NY,NY

Right. So on the map it's going up by 5s. So I started at 10 and connected all the 10s. Im just not sure if I've done it right because it doesn't look like a map at all. It looks like a bunch of random pencil thingies.

9. geoffb

No, it's not right as you've drawn it. You need to connect all the multiples of 5, drawing between two data points as necessary (e.g., if you were drawing the contour line for 30 m, it would go between 33 and 28). It might look something like: |dw:1353377851980:dw|

10. geoffb

11. NY,NY

wouldn't the 40 line in your picture have it's own line right on top of it? and the outer line that you've drawn, is it connecting 25 m ?

12. geoffb

The 40 is on its own, so it's really a matter of technique. It could also be marked by a point, but that is hard to see. As far as I can remember, it is common to draw a small circle around the peak if it happens to be a multiple of your contour lines (in this case, 40 is a multiple of 5).

13. geoffb

Yes, the outer line signifies 25 m in my example.

14. NY,NY

But i have connected all the multiples of five. I mean Im not finished, but most of the multiples ive connected them.

15. geoffb

Right, but when a contour is closed off it indicates a peak. For example, 14 and 18 in the upper-right corner. Those are not peaks. Taking a quick look at the numbers, your map should look more like this: |dw:1353380276652:dw|

16. NY,NY

so is it ok if some points dont have a circle around them?

17. geoffb

Absolutely!

18. geoffb

All they are is plotted points. Imagine you climb a mountain. You plot the elevation at every point possible. Then, when you get home, you put those elevations on a piece of paper. That's great, but it's hard to interpret. So, you decide to draw contour lines. Each line indicates (in this case) 10 m, 15 m, 20 m, etc. These contour lines give you a sense of the elevation gradient (i.e., change). Lines that are close together indicate steep hills, while lines that are far apart indicate very gradual hills.

19. NY,NY

20. NY,NY

i cant exactly seem to conncet the lines...

21. geoffb

That looks great! Looks like there's some trouble with the 40 m line below the 50 m peak, but overall you've done well.

22. NY,NY

how do you think i can connect that line? theres a 38 mark which is less than 30 so i cant put it in the circle...

23. NY,NY

less than 40 i meant *

24. geoffb

See the leg of the line on the left, that ends between 42 and 36?

25. geoffb

Bend it up, above 38 and below 45. Then do the same (the numbers to the right are the same). Then, take it above 38 to connect it at the 40.

26. geoffb

|dw:1353386235523:dw|

27. NY,NY

i dunt have space to connect the 20 line... or 15 or 10 should i just leave it unconnected? maybe the teacher will understand...

28. geoffb

Oh, I see what you mean. You just end them at the bottom of the map. |dw:1353387355947:dw|

29. NY,NY

oh ok. thanks :D

30. NY,NY

wow that took a long time...

31. geoffb

You did good!

32. NY,NY

thank you :D