NOTES Topo Maps.notebook symbols to show the surface A map that uses features of an area as if you were looking down on it from above. Otego, NY Apr 12 8:41 AM Unadilla, NY accurate information, such as: Used to provide highly Elevation Relief Slope of the ground surface Gradient 1
Common uses: Official: Highway construction Search and Rescue Government agency responsible for making topographic maps for our country: Geological Survey United States Recreational: Camping Hiking Elevation: height above Contour Line sea level : Isopleth connecting points of equal elevation Elevation of point A: Elevation of point B: Elevation of point C: 75 feet 45 feet 55 feet C.I. Contour : difference between two lines. Index Interval Contour Line: a contour line which is with a value. thicker labeled Depression Contour Line: Special contour lines cavity used to show a or on Earth s surface. Drawn like regular contour lines; however, the are inside crater marked on the with small called HACHURE MARKS dashes 2
Add to notes: The first line of depression is EQUAL to the previous normal contour line What are the correct names for each of these lines (Unless otherwise noted) Apr 18 7:23 PM What are the correct names for each of these lines Contour Line Add to notes: Depression Contour Index Contour 20 feet Contour Interval: 259 feet Maximum Elevation: 140 feet Maximum Elevation of the Crater: 81 feet Minimum Elevation of the Crater: 59 feet Maximum Depth of Crater: Spot Elevations: Elevations of points of interests Marked with an X Map Ratio (aka, Scale): Ratio that compares a measurement actual distance on a map to the Example: 1:24000 1 inch = 24,000 inches (2,000 feet) 1 cm = 24,000 cm (240 meters) 3
Difference Relief: in elevation between the highest lowest and point in an area 240 feet - 80 feet 160 feet ESRT (Page 1) Gradient (slope): Change of a field value between two points. rise run over Change in Gradient = Distance ELEVATION steepness Known as the of an area. Calculate the gradient: Gradient = 10,000 feet 5 miles = 2,000 feet/mile 1st Step: Use the provided scale to determine the DISTANCE 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 between the two locations 0 1 2 3 4 5 Find the gradient between points 'B' and 'D': 0.4 miles 4
Find the gradient between points 'B' and 'D': Tip: Gradient can be quickly estimated visually by realizing that contour lines that are steeper Close together = terrain flatter Farther apart = terrain Gradient = change in elevation distance = 1,500 ' 0.4 mi. = 3,750 feet/mile Where is the steepest part of this island Match the landform profile to the to its correct contours Match the landform profile to the to its correct contours Law of V s River valleys upstream Contour lines bend where they cross a river causing a v to be formed. upstream These v s point Can be used to quickly determine the a stream is flowing. 5
NOTES Topo Maps.notebook Law of V s River valleys upstream where they Contour lines bend cross a river causing a v to be formed. upstream These v s point direction Can be used to quickly determine the a stream is flowing. Useful Tip: Elevations will decrease when approaching a stream... and increase when going away from a stream. Apr 26 7:59 AM Apr 26 8:09 AM Apr 26 8:05 AM 6
Step 1: Select two points on a topographic map that you are interested in drawing a profile and connect them with a straight line: Step 2: Use a plain piece of paper as a straight edge to connect the two points and make tic marks on the plain paper at every point it contacts a contour line (or a stream): Step 3: Use lined paper and make an appropriate elevation scale along the left margin (starting slightly lower than the lowest elevation along your profile line) Use your tic marked piece of plain paper as the horizontal axis and plot the elevations on the field of the lined paper. Connect the plots with a smooth line to form the profile of the selected area. or simply a "dip" (not dotted) Practice Drawing Profile: 7