1. *these notes go on pages 19 AND 21 of your Plate Tectonics INB!!*
Topographic Maps
*these notes go on pages 19 AND 21 of your Plate Tectonics INB!!*

2. topography means “shape of the land”
topographic maps graph a 3D landscape on a 2D surface showing elevation
Mount Rainier, Washington

3. Contour Lines:
contour lines connect areas of equal elevation above or below sea level
index contours are darker with elevation marked
intermediate are lighter with no elevation

5. Contour Interval: the elevation change that each line represents
FORMULA: distance between index contours ÷ # of contour lines

6. Water Direction:
“Rule of V’s”: contour lines make V’s indicating direction of flow of rivers & streams
V’s point uphill
help map reader interpret elevations of intermediate contours around stream

8. Hills:
contour lines are increasing in elevation within other contour lines
closer lines are together, the steeper the slope

9. Depressions
dips or major holes in land (from sinkholes, volcanoes, etc)
perpendicular contour lines, called hachures, point into depression
Lip of depression is highest point

10. Benchmarks & Colors:
benchmarks: area of measured elevation in between contour lines (marked by an X or BM)
colors:
brown- contour lines
blue- water
green- forest, woods
black, pink & red- manmade structures

11. Gradient/Slope how steep a hill is (look how close lines are!)
formula:
= ∆ in elevation ÷ straight line distance
Units: m/km OR ft/mile

12. Slope
Steep Slope
Gentle Slope

13. Line A Distance = .5 miles
Elevation Change =
Slope =

14. Topo Map Profile:
cross sectional view along a line drawn through a topo map
HOW:
make a line through your map & label (X-Y, X-X’, etc.)
use edge of paper and make “ticks” every time a contour line intersects
record elevation next to each tick

15. X Y

16. transfer ticks onto a graph, or graph paper
connect the dots to get a side view along your line!

18. Map Projections
mathematical means of transferring info from 3D to 2D; different “views”
most have flaws because of curved surface
projections & flaws:
(1) mercator- distorts areas near poles; view entire world
(2) gnomonic- distorts areas away from
center point; view poles
(3) polyconic- distorts poles & Equator; view mid- latitudes
(4) globe- no flaws; view entire world to scale

19. Three most common types of
map projections are:
Mercator Projection
Polyconic Projection
Gnomonic Projection

20. Greenland Mercator map size
Map Distortions
Greenland Mercator map size
True size of
Greenland

21. Map Scales:
mathematical relationship between objects on a map and their true life size
ratio or fraction
larger the number on the right, greater the amount of area map covers
same unit on each side
bar scale gives quick visualization of distances on a map

23. Example: