TLW, with 100% participation Identify landforms on a topographic map Use contour lines to interpret terrain features and elevation Apply knowledge of weathering and erosion to predict effects on landforms Warmup: Land in your hand – hill/mountain, range, ridge, draw, spur, valley, depression, cliff, delta

The study of the shapes and features of the Earth’s surface.

Shows the 3D shape and elevations of an area of land in 2 D. Also known as Contour Maps

Blue lines/shapes - represent water features, such as streams and lakes. Brown – contour lines Black – Roads, buildings, railroads, other man made objects. Green – Woodland areas Red - Highways

Height above sea level

Sanger is 669 feet above sea level. The city of New Orleans is 6.5 feet below sea level. What does sea level mean?

Notice the two high points on the island. What is the elevation of the two high points?

PSC 121 Prince George's Community College Maps always have a scale printed somewhere on the map. For USGS maps it is at the bottom. On USGS the map portion below, the scale is 1:24,000. That means that 1” on the map is 24,000” on the ground or 1’ on the map is 24,000’ on the ground.

PSC 121 Prince George's Community College There are also scales that can be used to determine distance for many different units using a ruler and the map scale. 1 mile 1/2 mile 2000 feet 200 feet 1 kilometer

PSC 121 Prince George's Community College Elevation is indicated by contour lines. A contour line is a line of equal elevations (eventually a closed loop). All points on a contour line have the same elevation. 800 feet 700 feet htm

PSC 121 Prince George's Community College The elevation difference from one line to another is called the contour interval. On the map portion below the contour interval is 20 ft. 20 ft elevation increase 20 ft elevation decrease htm

PSC 121 Prince George's Community College The contour interval is usually printed on a topographic map. However, you can always calculate the interval from the lines with values. from the lines with values.

The difference between the highest elevation point and the lowest elevation point on a map Units = feet What is the relief of this map? What is the contour interval of this map?

 Contour lines are closely spaced on steep slopes.  Contour lines are widely spaced on gentle slopes.

 Contour lines near the top of a hill form closed, circular shapes. The top of the hill is higher than the highest closed contour line.

PSC 121 Prince George's Community College You can generate a profile of a landform from the contour lines on a topographic map. Simple contour map Click on image to see contours develop

 Depressions without outlets are shown by closed hatched contours. The contour lines have short lines on the inside that are pointing down slope. The bottom of the depression is lower than the lowest closed contour line.

Index Contour – Usually every 5 th line is printed darker and has an elevation printed on it.

1. Contour lines never cross

2. Contours form closed loops (even if not shown of the map.

3. Contours bend upstream (uphill) when crossing a stream.

4. The maximum possible elevation for a hill is “1” less than what the next contour “should” be. The highest possible elevation of the hill is just below the value of the next line that is not shown

Where a contour line crosses a stream or valley, the contour line bends to form a “V” that points upstream. In the upstream direction, the successive contours represent higher elevations.

PSC 121 Prince George's Community College How does water always flow? DOWNHILL How can we tell what direction (N,S,NW,ESE) is downhill?

PSC 121 Prince George's Community College You can look for elevation changes since water will flow from higher to lower elevations. Here the stream flows toward the northwest ft 2000 ft

PSC 121 Prince George's Community College You can look at the contour lines as they cross the stream. They will always point upstream. DownstreamUpstream

PSC 121 Prince George's Community College You can also look at where two streams merge. The merge will form a V that points downstream. Direction of flow

A map made of pictures of the Earth taken from a satellite orbiting the Earth.