IV-p5c Rule of Vs
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THE RULE OF V'S

"Knowing which way a river flows is often the key to being able to label contours correctly! Look at what happens to the contour lines in this picture when they cross a river! "
"They bend to form kind of a brown "V" shape! An upsidedown "V" in this case!"
"You can see the "V"s on the contour map too! "
"And the "V"s point upstream! "
"By the way, Lou! Make sure not to confuse the "V"s the contours make (the brown "V"s) with the "V"s made by streams where they join (the blue "V"s)! It's the brown "V"s we want! Here, the streams flow towards the south!
"The "V"s can be short or long, sharp or blunt, but they always point in the upstream direction! And the river flows the other way!"
"So here we can see that where the D contour crosses the river it forms a "V" (shown in green) that points west! That means west is upstream! And the river flows away from the west towards the east!"
"And in that case, the higher area that the D contour wraps around and encloses must be to the west, not the east! So, the D contour lies outside the 700 foot contours! It must be the next lower contour! It must be the 600 foot contour!"

LABELING CONTOURS - USING THE RULE OF 'V'S.

"Let's see if you're getting into it, Lou! From this contour map you should be able to tell in which direction the river is flowing, and you should also be able to label the contours! The contour interval is 20', there's a north arrow for direction, and the elevation of point X is 147'! That's all you need to know!"

 

INSTRUCTIONS: Indicate the direction towards which the river is flowing by writing one of the following directions in the box. (Use only capital letters!):

SE; NW; NE; E; SW; S; W; N.     Correct?:-

INSTRUCTIONS: Complete each of the sentences by placing a NUMBER in the appropriate box. DO NOT write the numbers as words. Click the button to the right of the word 'Correct' to see if your answer was correct.

1. The elevation of contour A is:- feet.     Correct?:-

2. The elevation of contour B is:- feet.     Correct?:-

3. The elevation of contour C is:- feet.     Correct?:-

 

 

 

Our thanks to Professor of Geology, David Leveson at Brooklyn College , CUNY
for his kind permission to use this copyrighted material.  

http://academic.brooklyn.cuny.edu/geology/leveson/core/linksa/maptop.html