Interpreting a Topographic Map Today’s Objective: Interpreting a Topographic Map Do Now: When would knowing your altitude be important? Notes Packet

** Important Vocabulary ** Isoline - Is a general term used to describe lines that connect points of equal value on a map. Types of Isolines - Isotherms - Lines connecting equal temperatures Contour Lines - Lines connecting equal elevations Isobars - Lines connecting equal pressures

Index Contour Line Heavy lines spaced at a predetermined labeled elevations on a topographic map. Index Contour

Contour Interval - The vertical distance that separates EVERY contour line on a topographic map. What is the contour interval of this map? Benchmark – tells the real elevation at that point

Estimating Elevation Label the contour lines based on the map interval Find the contour line before and after the point you are trying to determine You’re answer should be a point in between those lines Give a possible elevation for point “a” Contour Interval = 10 m 10 . a 20 30 . b . c Give a possible elevation for point “b”

What is the highest possible elevation of point “c”? The highest possible point on a contour map will always be one unit less than the next possible contour line. Contour Interval = 10 m 10 . a 20 30 . b . c Give the HIGHEST possible elevation for point “c”

What about the LOWEST possible point? The lowest possible point on a contour map will always be one unit more than the lower contour line. Contour Interval = 10 m 10 . a 20 30 . b . c Give the LOWEST possible elevation for point “c”

Where would it be easier to hike? Why? B has a gentle slope, or gradient.

Gradient Refers to the steepness of the land (slope) Closer contour lines = steep slopes. Further contour lines = gradual slopes. Which side of the hill is the steepest? WHY? N

Contour lines will either Run off the map or Close on themselves to create circles

Contour lines will NEVER cross. If contour lines touch they represent a very steep gradient, otherwise called a cliff.

Closed contours with hachure marks represent depressions (holes). Hachure Contours

The contour line with the marks, or hachures , has the same elevation as the line before it. 50 Meters

River and Streams When a river or stream crosses a contour line, the contour line bends and points upstream. upstream downstream Upstream is where the river starts, higher elevation. Downstream is where the river ends, lower elevation.

What is the contour interval? What compass direction is Eagle Mt. located? What is the elevation at the edge of Wolf Pond? What is the elevation of point B? Point C? Point E?

What is the distance from B to D? (scrap paper) Place an “X” on the map where the steepest location would be. What direction is Deer River flowing? Explain how your know.

What is the contour interval of this map?

If given the contour interval, can you label the lines?