I. Contour Maps--Introduction 20 September 2007

RELIEF: difference in elevation between two points.

Why are there two roads from Louberg to Luluville?.

Dingle Rd. goes around the Mts. while Bo Ring Way goes UP & OVER the the 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 its CONTOUR LINES.

Looking down from above.

Contour Interval (C.I.)=250 feet. --Labeling EVERY line with an elevation gets too 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 inside a contour is supposed to be HIGHER than the contour.

DEPRESSION CONTOUR: indicated with “teeth” called HACHURES. Hachured contours: a point inside a contour is lower than the contour. --A point outside a contour is higher than 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