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