Unformatted text preview: Mapping Mapping What is a map? What is a map? It is a representation of something (Earth, stars, solar system, a building, etc… Uses of Maps Uses of Maps To determine where you are going. Used to locate various places To act as a model of Earth’s surface. To show the distribution of various features or types of materials. Quick Review of Latitude and Quick Review of Latitude and Longitude Latitude – Measured in degrees North and South of the Equator. – Lines drawn parallel to each other running west to east. Quick Review of Latitude and Quick Review of Latitude and Longitude Longitude
– Measured in degrees East or West of the prime meridian. – Lines drawn running North and South. Topography Topography The lay of the land. Shows relief using contour lines. – Relief highs and lows of Earth’s surface. – Relief can be calculated Take the difference between the highest point and the lowest. Ex: Mountain peak 20 m. lake 10m
– – 20m 10m= 10m The relief of this area is 10m Lines on topographic maps. Reading a topographic map Reading a topographic map Contour Lines Connect points of equal elevation. – Everything connected to that line has the same elevation. – Elevation the distance something is above sea level. Sea level= 0m or 0ft. Reading a topographic map Reading a topographic map Contour Intervals Contour interval gives the difference in elevation between 2 contour lines.
– Another indicator of height. – Shown on maps as C.I.= 10ft. – Used to count contour lines. How it will look on a map C.I.= 1000ft Reading a topographic map Index Reading a topographic map Index Contours A index contour is a contour line that is accentuated in thickness and is labeled with the appropriate measure of elevation. Index contours occur every fifth contour line. Help the map user read elevations on a map. Red arrows indicate location of index contours. Reading a topographic map Reading a topographic map Streams
The direction a streams is flowing is shown on a topographic map by the way a contour line crosses the stream. Streams are shown as a blue line on maps. When contour lines cross a stream it looks like an upside down V. The point in the V points upstream. It opens in the direction the water is flowing. Depression contours Reading a topographic map Reading a topographic map Depression Contours show areas of lower elevation. Drawn like contour lines with marks on the inside. Hachure marks tick marks on inside of closed circle. Reading a topographic map Hills Reading a topographic map Hills Hills are represented on a topographic map by a series of concentric contour lines in a rough circle Reading a topographic map Slope Reading a topographic map Slope Closely spaced contour lines represent steep slopes. Widely spaced contour lines represent gentle slopes. Reading a topographic map Reading a topographic map Benchmarks A benchmark is a place where exact elevation is known. – Shown by a B.M. on map – Ex: BM 60 Reading a topographic map Colors Reading a topographic map Colors The colors on a topographic map are symbolic of different map features. Blue = water Green = forest Brown = contour lines Black = cultural features (buildings, place names, boundary lines, roads, etc.) – Red = principal roads – Pink = urban areas – Purple = revisions to an older map, compiled from aerial photos. If an area has become urbanized, this may be shown as purple shading on the new, revised map. – – – – Reading a topographic map Map Reading a topographic map Map Scale
Map scale indicates your distance along the ground, or the amount of ground covered by the map. USGS United States Geologic Survey
– – Ratio 1:24000 one unit on the map is equal to 24,000 units of the same size on the ground.
– Or after converting 1 inch = 2000ft. Ex:1 inch on the map = 24000 inches on Earth. Bar scaleindicated by a line or bar with distances marked in miles, feet, or kilometers. Reading a topographic map Map Reading a topographic map Map Scale A topographic profile is a crosssectional view along a line drawn through a portion of a topographic map. – It is like taking a slice out of a portion of the Earth and looking at it from the side. Reading a topographic map Reading a topographic map Profiles ...
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- Spring '08
- topographic map, Longitude Latitude