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## Topographic Maps

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**There are Planimetric (street) maps, and Physiographic**(bumpy) maps. TOPOGRAPHIC Maps combine information from these two into one map!**TOPOGRAPHY: Three-dimensional characteristics of land.**Topographic maps show elevation as well as distance on a map 3 – D land form 2 – D surface Topographic Map of the same land form. . . .**Can you see the relation-ship? Point out some common key**locations, if you can. . .**There are MANYTopographicMap Symbols, but you will only be**held responsible for a few. .**Copy/draw the following common patterns/symbols with your**teacher: Depression contour: Hilltop/mountain top feature: Stream or canyon: Cliff or steep slope: Flat or gentle slope:**Map Scale (FRACTIONAL)**“COLON” • Found in bottom margin of topo map. • Scale will look something like this 1:24,000 • This means one unit of measurement is equal to 24,000 units of measurement. • Example: One cm on the map is equal to 24,000 cm on the ground. • Same as saying the map is 1/24,000 the size of the area it represents.**Map Scale (GRAPHIC)**“BAR” 1.0 ½ 0 1.0 The kind you can use As a bar of measure that you hold up to a map to find distance Map Scales here**Some map Scale advice. . . .**• The larger the second number is in the ratio, the less detail seen on the map (zoom out). 1:24,000 scale 1:75,000 scale**CONTOUR LINES**• A line connecting points of the same elevation. INDEX CONTOUR – has an elevation number on it INTERMEDIATE CONTOUR – has no number**Basic Contour Line Rules**(1) Where a contour line crosses a stream or valley, the contour line bends to form a “V” that always points upstream. Valley “V” points upstream**(2) Contour lines are widely spaced on gentleslopes or**flatter land. (3) They are closely spaced on steep slopes. (4) Evenly spaced contour lines indicate a uniform slope.**(5) Contour lines do not cross or intersect each other**(6) All contour lines eventually close on the map or beyond its margins. (7) Contours that form closed loops indicate a hill or mountainous structure.**INTERVAL – How many feet in elevation you go up with each**line. . . High Index Line Number – Low Index number Number of Spaces in Between Contour Interval = 200 – 100 5 spaces Contour Interval = 20 feet**Let’s say point D is at 500 feet, and the Contour Interval**= 20 ft. Name the elevations of all the letters. . .**What is a Benchmark?**• A benchmark is a known elevation at a certain point • Usually seen at high elevations Bench Mark (X) – elevation 4392**A person’s PROFILE is a side view of the contours of their**face.A land profile is the same thing.**PART II: How to Make a PROFILE of a Topo Map. (This is**making a “side view” of a land form from a “flat” map.) Area of Profile