I. Contour Maps--Introduction 20 September 2007 RELIEF: difference in elevation between two points.

I. Contour Maps--Introduction

20 September 2007

RELIEF: difference in elevation between two points.

Why are theretwo roads fromLouberg to Luluville?

.

Dingle Rd. goes around the Mts.while Bo Ring Waygoes UP & OVER thethe Mts.

CONTOUR LINE: connects points of EQUAL elevation (BROWN LINE)

A map with topographic

contours.

CONTOUR INTERVAL: distance in elevation between consecutive contour lines

The island from above.

II. Labeling Contours

Island with itsCONTOUR LINES.

Looking downfrom above.

Contour Interval(C.I.)=250 feet.

--Labeling EVERY line with an elevation getstoo cluttered.

Instead, we use an INDEX INTERVAL: every FIFTH line is labeled and thicker.

BENCHMARK: an exact point of elevation that can be marked with an X, +, or BM.

Notice: any place INSIDE a contour line is HIGHER than the contour line. Any place OUTSIDE a contour line is LOWER than the contour line.

III. The V Rule

Contour lines bend to form a V when they cross a river. The V points upstream. Therefore, the river flows the other way.

NOTES ARE FINISHED FOR TODAY (20 Sept. 2007)

Work on assignment until the bell.

IV. Depression Contours—Getting into and out of a hole.

20 September 2006

The highest point (1397’) is on the rim between its outer slopes and crater.

C.I.=200’

Contours betw. 517’ and 1397’ are fine. But, you cannot have a 1200’ line INSIDE a 1200’ line, and 1000’ line INSIDE a 1200’ line.

Everything insidea contour is supposed to beHIGHER than thecontour.

DEPRESSION CONTOUR: indicated with “teeth” called HACHURES.

Hachured contours:a point inside a contour is lowerthan the contour.

--A point outside a contour is higherthan the contour.

From the rim, the land goes down on BOTH sides—towards the outside of the volcano and inside the crater.

V. Contour Spacing and Steepness

NOTICE: the slope from atop Mt. Tipster is much STEEPER down to sea than the slope from atop Mt. Riddle down to sea.

NOTICE: where the slopes are STEEPER the contour lines are CLOSER. Where the slopes are GENTLER the contour lines are FURTHER APART.

What happens if you have a VERTICAL cliff?????!!!!!!!

With a cliff, the contours will come together and merge. THIS IS THE ONLY TIME CONTOURS TOUCH!

THE END

Work on assignment for remainder of class.

20 September 2006