1. Unit 8 - Use of Maps John Guthrie, USGS

2. Unit 8 - Use of Maps Demonstrate the ability to shoot a bearing (azimuth) off a compass Explain the importance of knowing the proper declination of an area Given a compass with proper declination and map (local area), determine an azimuth and the distance between two points.

3. Topographic Maps Show contour & elevation

4. Topographic Terms and Features Contour line Contour interval Line spacing  Wide = gentle slope  Close = steep slope Slope direction Lines point downhill on ridge tops Lines point uphill where they cross drainages You can get approximate elevation for any point on the map

5. Organization and Scale 15-minute series vs. 7.5-minute series 7.5 most common 1" on the map = 24,000" on the ground (.38 mile) “Sectional” maps are composed of “quadrangles” A sectional map might represent Colorado Each quadrangle is named for a city or feature found within the quadrangle Each quadrangle is 23,040 acres  Quads are further subdivided into “sections” for pinpointing locations

6. Parts of a Section

7. Public Land Survey System

8. Topographic Measurements TOWNSHIP36 Sections SECTION640 Acres 1/2 SECTION320 Acres 1/4 SECTION160 Acres 1/8 SECTION80 Acres ACRE43,560 Sq. Ft. ACRE208.71 ft. Square ACRE100ft.x435.6ft ACRE75ft.x580.8ft ACRE50ft.x871.2ft ROD16.5ft. CHAIN66ft. CHAIN 100 Links CHAIN4 Rods MILE5,280 ft. MILE320 Rods MILE80 Chains