Contours are Continuous

Some contour lines may close within the map, but others will not. 

In this case, they will start at a boundary line and end at a boundary line.

Contours must either close or extend from boundary to boundary

 

  Continuous Contours-cont.

Is the topo map correct?

•No 

•Contour 1040 is very unlikely

•This would only occur if there were a long vertical wall.

 

 Contour lines are parallel
 

Two exceptions:

1.They will meet at a vertical cliff

2.They will overlap at a cave or overhang. 

3.  When contour lines overlap, the lower elevation contour should be dashed for the duration of the overlap.

 

 3. Valleys and higher elevation
A series of V-shapes indicates a valley and the V’s point to higher elevation

  
U shapes and ridge

A series of U shapes indicates a ridge.  The U shapes will point to lower elevation

  Contour Spacing 

Evenly spaced contours indicate an area of uniform slope.

Unevenly spaced contours indicates an area with variable slope.

  Hills and Depressions  

A series of closed contours with increasing elevation indicates a hill.

Hills may be identified with a “+” with the elevations

  Hills and Depressions--cont.

vA series of closed contours with decreasing elevation indicates a depression.

vDepressions may be identified with a “-”.

  Hachures   

 

vHachures are short lines which are perpendicular to the contour line.

vUsed to indicate a hill or a depression.

vNot used on modern maps.