Part 2:Topographic Maps Essential Questions: How can scale, distance, slope, relief, and profiles be determined from analyzing topographic maps? Essential Understandings: Topographic maps and satellite imagery are two-dimensional models that provide information defining three-dimensional landforms. They contain extensive information related to geographic as well as human structures and changes to the land surface, and are useful in understanding geological processes.

Topographic Maps What Students Should Be Able To Do:  Read and interpret maps, including legends, lines on maps and scales.  Identify a hilltop, stream, and valley on a topographic map.  Construct profiles from topographic contours.  Determine distance and relief on a map.  Collect, analyze, and interpret data collected from GPS technology.  Interpret landmarks and geological features from aerial photographs.

What do Topographical Maps Show? Main purpose- 2D model used to show elevations above sea level (0 ft). Other things they show Landforms – hilltops, depressions, valleys, ridges, cliffs, etc. Shown by specific shapes of contour lines. Direction – almost all topo maps have north at the top. Topographic maps have two arrows pointing towards north. One points to magnetic north and the other to geographic(true) north. Cultural Features – buildings and structures. Shown by specific symbols and colors. Landscapes- types of vegetation or surface cover. Also shown by specific symbols and colors

Map Scales Large scale vs.____________scale Large scale shows the map ___________ to the actual size of the land it is representing. It produces a bigger picture, but shows less area. The numerical scale has a smaller number. _________ scale shows the map farther from the actual size of the land it is representing. It produces a smaller picture, but shows more area. The numerical scale has a larger number.

Small scale vs. large scale 1: :100000

Determining land distances from maps. GRAPHICAL SCALE 1) Take the edge of a piece of paper and mark the distance from point to point on it. 2) Hold the first mark on the zero (0) position of the scale. 3) Mark off the first mile and label it 1. 4) Move that mark back to the zero and mark off the next mile/kilometer and label it 2. 5) Continue until your point is less than a mile on your scale from the last mark you labeled. 6) To find tenths of a mile/kilometer you need to use the portion of the scale to the left of the zero position that the mile/kilometer is divided into ten sections. Hold your last mark at the beginning of the whole scale and mark off each tenth. When you are done add them all up to determine your distance.

5200 Point A Point B A B Mark your tick marks on the edge of your paper from point to point

5200 A 1 2 B Put your first point on 0 and mark off every mile as you move along the edge of your paper towards B. Notice there is still more distance between the 2 tic mark and the B tic mark. You will need to determine the remaining distance in tenths of a mile. ?

A 1 2 B Put the last mile mark at the very beginning of the graphical scale and estimate how many tenths of a mile the point is from the mile mark and add them together. * In this case B is roughly.2 miles past the 2 mile mark, so it is about 2.2 miles from point A to B on the map.

Practice Determining Land Distances Using a Map (use scale from previous frame) Point A-B = Point B-C = Point C-D= Point D-E = Point E-F = 5200 Point A Point F Point E Point D Point C Point B

Map View vs. Profile View -You can see that a contour line is drawn on the map to show sea level and other lines are drawn at every 10 ft interval on the map for the island (contour lines represent elevation above sea level). - the shapes of the lines represent specific shapes of the land (topography)

How are Topographic Maps Made? -Land surveyors gather data in the field to make the maps. They use a GPS and/or transit to locate points plus get elevation readings to take back to a cartographer that draws the map. -The following images are one way you could ____________ a topographic map being made.

Island with ocean surrounding it

If the ocean were to rise above the island we could mark its rise every 10 ft on the island and the map. When the water drops we would have the topo map for the island. Watch.

Contour Lines Usually ______________in color Connect points of the same exact elevation. _________________are bold contour lines that have a number printed on them. These are what show elevation above sea level and their shapes tell you which landforms are present.

Contour interval- the ___________ in elevation between contour lines next to each other.

Contour Interval Practice – use the formula 900

Contour Interval Practice – use the formula

Contour Interval Practice – use the formula

Contour depression lines - contour lines with ________________________ _______________________________ direction indicating a low-lying depression on the land.

Rules for Contour Lines 1. ______________ between adjacent contour lines is constant - contour interval. 2. Contours crossing a stream form a “V”-pattern with the V _______________. 3. Contour lines _______________ cross or split.

4. The spacing of contour lines reflects the ___________________of the slope contour lines far apart = _______slope contour lines close together = _________ slope 5. ______ and knobs are shown by closed contours. 6. Closed depressions are indicated with hatchures pointing down hill and have the same elevation as the lowest contour line elevation next to it. 7. The shape of the contour reflects the shape of the ground.

Check it out! 5200

Depressions

Other Landscapes

Practice Determining Exact Elevations Point A- Point B- Point C- Point D- Point E- Point F Point A Point F Point E Point D Point C Point B

Estimating Elevations You will estimate elevations for points that aren’t exactly on a contour line. Because topographic maps don’t show exact elevations between the contour lines we have to give a range of every possible elevation for that point. If asked to give a highest possible elevation then you would give the elevation that is one lower than the highest known contour line elevation next to it. In the case of a hill, the highest known contour line elevation will not be listed because it above the hilltop. You will still use that one to determine the highest possible elevation for the point.

If asked to give a lowest possible elevation then you would give the elevation that is one higher than the lowest known contour line elevation next to it. In the case of a depression, the lowest known contour line elevation will not be listed because it below the depression, underground. You will still use that one to determine the lowest possible elevation for the point.

Practice Estimating Highest and Lowest Possible Elevations Point G Point H Point J Point M Point I Point L 5200 Point K Point Lowest Possible Elevation Highest Possible Elevation

Relief - the ________ in elevation between two points. (Subtraction) Point A Point C Point B Determine the relief between the following points: A-B = A-C = B-C =

Determining Compass Direction We can divide the compass direction even further: -Look at the line between N and NE -You will use all three letters to label the line, but use the single letter first, then add the double letters. -It would be NNE -Label the rest

Magnetic North vs True North Earth has a magnetic field that surrounds the planet and protects us for harmful cosmic rays. A compass points at magnetic north, but the north pole isn’t magnetic north- it is true north or geographic north. True north is one of the points on earth that it rotates around. The other point is the south pole. Together they make Earth’s axis. o If looking at your compass that is pointing north you would rotate the the bezel so that the N representing north was above your needle pointing north. o You would then look at the topo. map of the area to see how many degrees you would have to adjust it.

Magnetic North vs True North The people using this map were standing at the star and wanted to go 1.25 miles due north. Because they didn’t adjust their compass they went towards magnetic north and ended up being.32 miles of course.

Magnetic declination

Drawing Profiles from the Map Process: Take a piece of paper and pencil and put tic marks on the edge of your paper for the two points for which you are going to draw your profile. Keeping those tic marks on those points, without moving your paper, mark every contour interval that hits the edge of your paper and record its elevation. Make an X-Y axis graph. X-axis labeled distance, Y-axis labeled elevation. Identify your highest and lowest contour elevation and make your Y axis numbers one interval higher than your highest contour elevation and one interval lower than your lowest contour elevation. Hold your paper with the tic marks along your X axis with your left point at the beginning of it and project your points up to their proper elevation.

Be sure to mark any roads, rivers, buildings, etc that also hit the edge of you paper and label it on your profile line.

Part 3: Other Mapping Strategies Essential Questions: How have different mapping techniques helped to diagram the surface of the earth? Aerial imagery Satellite imagery Essential understandings: Scale relates to actual distance

______________: an image captured from above/aircraft. Ex: Football stadium and high school campus

_____________________: consists of images of earth or other planets obtained by satellite Ex: Google Earth