Term | Definition |
topographic map | a 2d representation of a 3d geologic feature |
contour lines | lines of equal elevation; every point=same elevation; these lines infer the 3rd dimension on a 2d map. |
contour interval | the space between contour lines representing the difference in elevation |
types of data from a topographic map | relief, gradient, benchmark |
relief | total difference in elevation shown on map; subtract the lowest elevation on the map from the highest elevation |
gradient | the slope of a given area of a map; divide the rise (elevation=vert. component) by the run (distance=horiz. component); usually calculated in feet/mile |
benchmark | a position of known elevation |
map scale | 1: 24,000; 1 inch on the map= 24,000 inches on the earth, for example |
magnetic declination | difference between geographic (true north) & magnetic north; because earth's magnetic pole isn't centered on the geo. N.P.; important for navigation of map & compass |
cross section | a vertical cut of a geologic feature |
topographic profile | cross sections which depict elevations & slopes along a given line |
vertical exaggeration | doubling the unit spacing on the y-axis for greater resolution |
aerial photos | pictures of earth taken from airplanes |
satellite image | pictures of earth taken from satellites |
stereopair | a pair of air photos that partially overlap to view a 3d structure |
stereoscope | device which allows view in 3d using a stereopair |
Contour Line | A line on a map that traces locations where the value of a variable is constant. For example, contour lines of election trace points of equal elections across the map. All points on the "ten foot" contour line are ten feet above sea level. |
Section | Unit of subdivision of a township; normally a quadrangle 1 mile square with boundaries conforming to meridians and parallels within established limits, and containing 640 acres as nearly as practicable. |
Topography | The shape of Earth's surface or the geometry of landforms in a geographic area |
Name one Feature of Contour Lines | They do not cross. They are line of equal evalution |
What do maps shows? | Water, Depression in Ground, hills, roads, townships |
What does it mean with contour lines are "bunched" together. | Shows an area that is steeper |
Where can you located the name of a quadrant on a map | Upper Right Corner |
Graphic Scale or Bar Scale | Is a bar that is divided into segment that show the relationship between distance on the map and actual distance on EArth. |
What do Map Scales show? | Expresses the the relationship between distance on the map and actual distance on Earth's Surface |