Maps

1. Maps Mr. Martin

2. Models • Model of Car • Advantages • Disadvantages • Name a Model of the Earth • Globe • Advantages • Disadvantages • Maps • Advantages • Disadvantages

3. Direction • Axis • Geometric north • Cardinal Directions • North, South, East and West • Compass Rose • Magnetic North • Compass • 360 degrees • Magnetism of Earth • Declination • NOAA Declination tool - http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp

4. Latitude • Latitude – • Northern Hemisphere - 0 (equator) to 90 degrees north (north pole) • Southern Hemisphere - 0 (equator) to 90 degrees south (south pole) • Measuring angle to sun at highest point with adjustment for time of year (NEVER LOOK AT SUN) – see http://www.pbs.org/weta/roughscience/series1/challenges/latlong/ • At night angle of north star

5. Longitude • Measures degrees east or west of the Prime Meridian – 0 degrees • The Prime Meridian runs through Greenwich, a district in London, England • 0 to 180 degrees east of Greenwich • 0 to 180 degrees west of Greenwich

6. Longitude and Time • Every 15 degrees represents one hour difference in time from Greenwich • 360 degrees/24 hours = 15 degrees per hour • If you know the time in Greenwich and you know the local time, you can calculate your longitude • Local noon can be found when the sun is in its highest point in the sky • Greenwich time can be found with an accurate clock set to Greenwich time

7. Longitude and Time Continued • While accurate clocks are taken for granted today, accurate clocks were not available in the early 18th Century especially on the high seas • English clockmaker John Harrison in the later half of the 18th Century devised a reliable and accurate clock • He won a prize from the British Parliament • His invention saved thousands of sailors’ lives

8. Designating any Location on Earth with Latitude and Longitude • Latitude and longitude is like the coordinate plane we use in math • We can designate any location on Earth by stating its latitude and longitude • Looking at the globe, what is the latitude and longitude of Solana Beach? • Latitude – about 32° North Latitude • Longitude – about 118° West Longitude

9. Designating Latitude and Longitude Continued • With a larger map, we could estimate the latitude and longitude more accurately • With Satellite Data, we can get the latitude and longitude of the front door of Keystone Academy • 32°59’22.16”N latitude, 117°15’34.27”W longitude

10. Google Earth • Allows an aerial view of anywhere on Earth • Based on satellite images You are here! Latitude and Longitude data

11. GPS – Global Positioning System • Developed from military satellite information • Became available to the public in the late 1980s and early 1990s • Based on data from 24 satellites • Receiver can pinpoint your latitude and longitude within a few meters • Most receivers now also are loaded with base maps showing your position on a map with directions to a designated position • Has revolutionized vehicle, marine and wild lands navigation in the last two decades

12. GIS - Geographic information system • “A GIS is a computer system capable of capturing, storing, analyzing, and displaying geographically referenced information; that is, data identified according to location.” • http://egsc.usgs.gov/isb/pubs/gis_poster/ • GIS in recent years has greatly enhanced natural resource planning and management • Can have multiple layers showing e.g. elevation, satellite images and resource information

13. Remote Sensing and Landsat • http://landsat.gsfc.nasa.gov/

14. Problem – How to show a sphere on a flat piece of paper! • Mercator Projection • Conic Projection • Azimuthal Projection

15. Information Shown on Maps (pages 44-45) • Title • Maps scale • Graphic scale • Verbal scale • Representative function • North arrow • Legend • Date

16. Topographic Maps • Topographic maps show elevation by lines of equal elevation • Topography is the detailed description of the surface features of a region • Contour lines show lines of equal elevation • Model • Contour interval is the difference in elevation between one contour line and the next

17. Model of Topographic map • http://www.ehow.com/print/how_5824744_make-topographic-mountain-map-school.html

18. USGS Topo Maps • The United States Geographical Survey, a federal government agency, makes detailed topographic maps • USGS Topo maps are generally 7.5 minute maps – They are 7.5 minutes of latitude by 7.5 minutes of longitude. The areas vary between 49 to 64 square miles depending on latitude. http://egsc.usgs.gov/isb/pubs/booklets/usgsmaps/usgsmaps.html

19. More on Topo Maps • Contour intervals on USGS maps is 20 feet with darker lines every 5 lines or 100 feet • Close lines on topo maps mean the terrain is steeper • Widely spaced lines mean the terrain is flatter • Concentric circles mean a (conical) mountain top • Concentric circles with hash marks mean a depression like a crater • V shape means valleys. The point of the “v” points uphill

20. USGS Maps on Internet • In addition to paper maps you can buy, USGS provides all its topo maps online for free! • http://nationalmap.gov/ • Quickstart guide - http://nationalmap.gov/ustopo/quickstart.pdf • Store - http://store.usgs.gov/b2c_usgs/b2c/start/(xcm=r3standardpitrex_prd)/.do