1 / 72

# C ONTOURS - PowerPoint PPT Presentation

10. 9. 8. 7. 6. 5. 4. 3. 2. 1. C ONTOURS. What are contours?. Imaginary lines Drawn on a map Connecting places Which are at equal elevation (height above sea level). How are contours drawn?. S. U. R. T. Q. E. P. G. D. F. B. M. A. C. L. I. J. H. O. K. N. 238.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about ' C ONTOURS' - rowena

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

9

8

7

6

5

4

3

2

1

CONTOURS

• Imaginary lines

• Drawn on a map

• Connecting places

• Which are at equal elevation (height above sea level)

How are contours drawn?

U

R

T

Q

E

P

G

D

F

B

M

A

C

L

I

J

H

O

K

N

240

252

276

263

297

279

280

300

317

320

285

325

314

289

309

298

280

254

281

264

240

240

252

276

260

260

263

280

297

300

279

280

.300

317

320

285

325

314

320

289

309

300

298

280

280

280

254

281

260

264

• The difference of elevation between two successive contours

• Contour interval on the toposheet is 20 meters.

Every 5th contour, with height mentioned

• All places on the contour line lie at the same elevation

• Contours never intersect each other

• Contour interval (difference between two successive contour values) is uniform throughout the map

• All contour values are multiples of the contour interval

• Height of any place on map can be determined

• Widely spaced contours

• Gentle slope

• Closely packed contours

• Steep slope

• Overlapping contours

• Vertical slope

200m

100m

200m

100m

300m

200m

100m

300m

200m

100m

300m

200m

100m

Let’sadd contour lines for every 50 meters and see if that helps.

300m

200m

100m

350m

300m

250m

200m

150m

100m

50m

350m

300m

250m

200m

150m

100m

50m

If you said somewhere between 200m and 250m you are right!

350m

300m

250m

200m

150m

100m

50m

350m

300m

250m

200m

150m

100m

50m

If you said 50m or just under, you’re right!

350m

300m

250m

200m

150m

100m

50m

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

Think you know our elevation now? your right!

More than 300meters

But less than 350meters

• More than 350 meters, less than 400 meters

More than 100 meters, elevation?

less than 150 meters

FORM LINES elevation?

Drawn where it is not possible to draw contours and there is a prominent relief feature which is lesser in height than the contour interval

Types of slopes elevation?

Uniform Gentle Slope elevation?

320

280

240

260

300

220

Uniform Steep Slope elevation?

320

260

300

240

220

200

180

280

160

140

Concave Slope elevation?

Concave Slope elevation?

240

220

320

260

280

300

Convex Slope elevation?

Convex Slope elevation?

Features of Contour Diagrams elevation?

• Spacing gives idea of slope

• Shape of contours resembles shape of relief feature in ariel view

• It is possible to visualise the shape of the relief feature

VISUALISATION elevation?

320 elevation?

300

280

260

CONICAL HILL

320 elevation?

300

280

260

ASYMMETRICAL HILL

320 elevation?

300

280

260

CIRCULAR PLATEAU

260 elevation?

320

280

300

RIDGE

260 elevation?

320

280

320

300

240 elevation?

220

300

260

200

280

340 elevation?

280

260

240

320

220

200

300

180

V SHAPED VALLEY

340 elevation?

280

260

240

320

220

300

200

WATERFALL

An Escarpment elevation?

CONTOURS: elevation? 45 D/7

9293: Ridge

9289: Ridge (uniform)

9390: Ridge (steep)

9489: Hill

7975: Conical hill

9284: Conical hill

9782: Escarpment