3Presented by: Mark A. Van Hecke Road Scholars National Event Supervisor1999 and 2000
4OBJECTIVES:Determine how topographic maps are configured on the Earth’s surfaceLocate marginal information on USGS topographic mapsDetermine approximate and exact geographic coordinatesCreate a Student-Generated MapCreate a topographic map profile
5Topographic Maps How are they configured on Earth’s surface? Topographic Map Features
6Topographic MapsTopographic maps are highly detailed representations of natural and human features found on the surface of the Earth.One or more sets of topographic maps will be used in the Science Olympiad Road Scholars competition.
7Topographic MapsMost of the topographic maps used in the Road Scholars competition are 7.5” series quadrangles published by the United States Geologic Survey.The land area shown on each map represents about square miles of the Earth’s surface.
8Topographic Maps Longitude Latitude Lines of longitude and latitude are used to divide each degree of the Earth’s surface in half into 30 minute units, then in quarters to form 15 minute units and then in eighths to form 7.5” (minute) units.
9Marginal InformationMarginal Information found on USGS Topographic MapsNine Mental SectorsLocation of Features
10Marginal InformationTopographic maps are loaded with information that will help you find the location of things on the map and to understand the map and its features.We’ll begin in the upper-right corner and continue through the rest of the map in a clockwise-direction.
11Marginal InformationNortheast Corner The NE coordinates of the map are 31°22’30”N 89°07’30”W
12Marginal InformationSoutheast Corner The SE coordinates of the map are 31°15’N 89°07’30”W
13Marginal InformationSouthwest Corner The SW coordinates of the map are 31°15’N 89°15’W
14Marginal InformationNorthwest Corner The NW coordinates of the map are 31°22’30”N 89°15’W
16Geographic Coordinates You can use tic line information located on all four neatlines to help you determine approximate and exact geographic locations on topographic maps.
17Reading LatitudeRead upward from the bottom neatline along the right neatline. You should see a tic line along the margin labeled 17’ 30”
18Reading LatitudeLook directly across the map along the left neatline. You should see another tic line along the margin labeled 17’ 30”
19Reading LatitudeNow continue reading upwards along the right neatline. You should see a tic line along the margin labeled 20’
20Reading LatitudeRead directly across the map. You should see another tic line along the margin labeled 20’
21Reading LatitudeRead upward to the upper right corner of the map. You should see a tic line along the margin labeled 31° 22’ 30” You should see another tic line along the margin labeled 31° 22’ 30” if you read directly across to the left side of the map.
22Reading LatitudeAs you read latitude upwards, the number of minutes and seconds increases.Latitude measurements in the United States are always north of the EquatorMeasurement of latitude is the same on the right and left sides of the map.There are 2.5 minutes between each measured section
23Reading LongitudeLocate the longitude reading of 89° 07’ 30” printed near the lower right corner of the quadrangle.
24Reading LongitudeRead to the left along the bottom neatline until you reach the tic line marked 10’. Look directly across the map along the top neatline. You should see another tic line along the margin labeled 10’
25Reading LongitudeContinue reading to the left along the bottom neatline until you reach the tic line marked 12’ 30”. Look directly across the map along the top neatline. You should see another tic line along the margin labeled 12’ 30”
26Reading LongitudeContinue reading to the left along the bottom neatline until you reach the southwest corner marked 89° 15’ Look directly across the map along the top neatline to the northwest corner. You should see another tic line along the margin labeled 89°15’
27Reading LongitudeAs you read longitude from right to left the number of minutes and seconds increasesLongitude measurements in the United States are always east of the Prime MeridianAlthough there are 2.5 minutes between each section, lines of longitude are not equidistant.
28Geographic Coordinates Geographic Coordinates are formed at the intersection of lines of latitude and longitude
29Geographic Coordinates Northeast Corner The NE coordinates of the map are 31°22’30”N 89°07’30”W
30Geographic Coordinates Southeast Corner The SE coordinates of the map are 31°15’N 89°07’30”W
31Geographic Coordinates Southwest Corner The SW coordinates of the map are 31°15’N 89°15’W
32Geographic Coordinates Northwest Corner The NW coordinates of the map are 31°22’30”N 89°15’W
33Identifying Map Sectors You can use tic line information located on all four neatlines to help you identify the nine mental sectors of your topographic map.
34Identifying Map Sectors 123456789The tic line boundaries can be used to form the Nine Mental Sectors of topographic maps that can be used as a reference point to locate features
35Identifying Map Sectors The cross-hairs can be used to determine the approximate coordinates of features located near them.
36Exact CoordinatesLet’s use the Cartersville, MS map to determine the exact coordinates of the Mt. Zion Church in Sector 9
37Exact Latitude Coordinates To determine latitude:Measure the distance in millimeters (mm) from the bottom neatline to where the cross joins the main building.That measurement should be approximately 186mm
38Exact Latitude Coordinates Divide that measurement (186mm) by 192- the distance in mm from the bottom sector boundary to the top sector boundary.Your answer should be SLDN (some long decimal number).96875
39Exact Latitude Coordinates Multiply your answer by 150-the number of seconds in a 2.5’ topographic map sectorYour answer should beThis is the number of seconds that the building is away from the sector boundary
40Exact Latitude Coordinates Now, let’s convert our seconds to minutes…First round to the nearest ones-place which would give you 145 seconds…Then divide the number of seconds by 60 giving you 2 minutes and 25 seconds.
41Exact Latitude Coordinates Now, add the 02’25” to the value of the bottom sector boundary.If the bottom neatline measures 31°15’ and we add an additional 02’25”, then our latitude measurement for Mt. Zion Church will be:31° 17’ 25”N
42Exact Longitude Coordinates Measure the distance in millimeters from the right sector boundary to where the cross joins the main building on the Mt. Zion ChurchThat measurement should be 64mm
43Exact Longitude Coordinates Measure the distance in millimeters from the right sector boundary to where the cross joins the main building on the Mt. Zion ChurchThat measurement should be 64mm
44Exact Longitude Coordinates Divide that measurement (64mm) by 165-the distance in mm from the right sector boundary to the left sector boundary.Your SLDM should be
45Exact Longitude Coordinates Multiply your answer by 150- the number of seconds in a 2.5’ sector.Your answer should beRound that answer to 59 seconds (59”)
46Exact Longitude Coordinates Add 59” to the value of the right sector boundary.If the right sector boundary measures 89° 07’ 30” and we add an additional 59 seconds, your answer should be:89° 08’ 29”W
47Exact Longitude Coordinates The exact geographic coordinates of the Mt. Zion Church are: 31° 17’ 25”N 89° 08’ 29”W
48Student-Generated Maps Orientation of a MapUSGS Topographic Map KeyDrawing the Student-Generated Map
49Student-Generated Maps Use a USGS Topographic Map Key as a guide to drawing features. First, determine the orientation of the paper.
50Student-Generated Maps Then, divide the paper into a four square grid. You do not have to put the directions. They are only a referenceNWNESWSE
51Student-Generated Maps Each square is in turn divided into four sections. This will help you place features in the correct placeNWSWSENW 1/4NE1/4SW 1/4SE 1/4
52ProfilingDrawing a Topographic Map Profile is a useful skill in determining where to place roads, pipelines, railroads and other construction projects.
53ProfilingTo construct a topographic map profile, draw a line on the map from where the profile is to begin from where it is to end as shown below
54ProfilingThen find the value of the highest and lowest contour lines that cross or touch your profile line.Add one contour line above the highest value and one below the lowest value to compensate for hills and valleys.
55ProfilingUse lined or graph paper similar to below. Place it just beneath the area you are profilingNumber the top line with the highest value and the bottom line with the lowest value as shown.
56ProfilingNumber the rest of the lines in sequence starting with the second line from the top. Lines should be numbered in accordance with contour interval.
57ProfilingPosition the paper on the map with the lines next to and parallel to the profile line.
58ProfilingThen from every point on the profile line where a contour line, stream, or any body of water crosses or touches, drop a perpendicular line to the line on your paper having the same value.
59ProfilingPlace a tic mark where the perpendicular line crosses the number line.
60ProfilingAfter all of the perpendicular lines have been drawn and tic marks placed where the lines cross, connect all tic marks with a smooth natural curve to form your profile