A Different Kind of Topography:

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Topographic Maps

Contour Mapping Topographic maps, also called contour maps, topo maps, or topo quads, are maps that show topography, or land contours, by means of contour lines.

Contour Lines Contour lines are curves that connect contiguous points of the same altitude.

Mt. Ginger Mt. Riddle Mt. Tipster

How Steep is the Slope? Where the slopes are steeper, the contour lines are closer together! Where the slopes are gentler, the contours lines are further apart!

Contour Interval difference in altitude between two adjacent contour lines Helps determine differences in elevation between two points Usually given at the bottom of the map. consistent throughout a map (in most cases)

What is Relief? Relief is the difference in elevation between the highest and lowest points in a region!

Rules of Contour Mapping 1. Every point on a given contour line is of the exact same elevation; that is, contour lines connect points of equal elevation.

Rules of Contour Mapping 2. Contour lines always close to form an irregular circle sometimes part of a contour line extends beyond the mapped area, so that you cannot see the entire line.

Rules of Contour Mapping 3. Contour lines never split. 4. Evenly-spaced contour lines represent a uniform slope. Closely spaced contour lines indicate a steep slope.

Cliffs or Sharps Drop Offs (Where the slopes are steeper, the contour lines are closer together!)

5. A concentric series of closed contours (like a target or bullseye) represents a hill. Hachure marks 6. Depression contours have hachure marks on the downhill side and represent a closed depression (hole).

Depression Contours

When Contour Lines Cross Rivers 7. Contour lines form a V pattern when crossing rivers or streams. The apex (point) of the V always points upstream (uphill) and the river flows the opposite way

8. In cases where slope orientation changes (like on top of a hill or in a valley), contour lines of equal elevation will be repeated.