ESRM 304 Autumn 2009 Phil Hurvitz

1. To Infinity and Beyond! Modern Methods ofMapping, Navigation, and Analysis ESRM 304Autumn 2009 Phil Hurvitz 1 of 42

2. Overview Mapping (again!??) GIS: it’s (much) more than just pretty maps Where y’at? Everything you ever wanted to know about GPS* *but were afraid to ask Ad hoc, ad loc, and quid pro quo. So little time, so much to know 2 of 42

3. Mapping What is a map (remember from last class session?) What makes a map what it is? [Discussion] 3 of 42

4. What is a (not) map? Why, in a modern/quantitative sense, are these not maps? Archaeologists have discovered what they believe is the earliest known map, dating from almost 14,000 years ago. (in Spain) A Neo-Babylonian (Persian Period, circa 500 BCE) copy of an original map dating to the Sargonid Period, circa late eighth or seventh century BCE 4 of 42

5. What is a (not) map? Why, in a modern/quantitative sense, are these not maps? • Short answer: • Lack of sufficient control/standardization of location of any particular feature (you could get lost easily) • Lack of regular measurement framework (how will new features be placed on the map in the proper location? A Neo-Babylonian (Persian Period, circa 500 BCE) copy of an original map dating to the Sargonid Period, circa late eighth or seventh century BCE Archaeologists have discovered what they believe is the earliest known map, dating from almost 14,000 years ago. (in Spain) 5 of 42

6. What is a (not) map? What really is a map (in a modern, quantitative sense)? • Short answer: a series of controlled, carefully structured X, Y, Z, M coordinates • Where X, Y, Z come from surveying (or some variation) in a standardized measurement framework, and matrix M comes from another measurement domain (e.g., soil type, forest stand species composition) Don’t get “Lost in Space” Use GPS and GIS! 6 of 42

7. Overview Mapping GIS: it’s more than just pretty maps (much more) Where y’at? Everything you ever wanted to know about GPS 7 of 42

8. GIS What does GIS do? • [Fundamentally important]: stores XYZM coordinates in a standardized digital framework  a land records database on steroids • Allows fine control over the display of these coordinates  a mapping function • [Ultimately important]: allows geometric and logical processing of XYZM data to support decision-making 8 of 42

9. GIS Why is GIS important in natural resource management? [Discussion] 9 of 42

10. GIS Why is GIS important in natural resource management? It allows (relatively) • easy, • quantifiable, • repeatable, and • standardized measurements of the landscape and its features. 10 of 42

11. Overview Mapping GIS: it’s more than just pretty maps (much more) Where y’at? Everything you ever wanted to know about GPS 11 of 42

12. Measurement methods Problems with traditional natural resource location measuring systems • Not always accurate or repeatable • Requires careful measurement, training • Requires careful note taking • Can take large amounts of time • Data storage issues • Field notebooks • Difficult-ish integration with other data (e.g., GIS, forest inventory) 12 of 42

13. Measurement methods Q: How do we solve the problems with traditional measurement methods? A: GPS and GIS 13 of 42

14. How does GPS solve these problems? Manual measurements are not always accurate GPS brings accuracy • 12 m accuracy for typical “camping” grade GPS equipment • 1 m for mapping grade equipment • Sub-centimeter accuracy for high-grade equipment • Measurement of mountain building • Measurement of plate tectonics 14 of 42

15. How does GPS solve these problems? Manual measurements are not always repeatable If you can get to the location (e.g., tree, inventory plot marker), your measurement will be repeatable within the precision of the equipment 15 of 42

16. How does GPS solve these problems? Requires careful measurement, training Equipment is “self-recording” • Does not require external data recording • Field notebooks are not necessary Does not require specialized training • No mathematics • “1 or 2 day” training 16 of 42

17. How does GPS solve these problems? Requires careful note taking • Equipment frequently contains digital data logger • Locational and informational data are stored digitally in the data logger • Field notebooks are not necessary 17 of 42

18. How does GPS solve these problems? Takes large amounts of time • Measuring lines (e.g., roads, trails) is as fast as walking or driving • Measuring polygons (e.g., stands, treatment units) is as fast as walking • Measuring point locations can be as fast as stopping and pushing a few buttons 18 of 42

19. How does GPS solve these problems? Data storage issues • Data are stored digitally; transferred digitally • Data backup and transfer on magnetic, solid state, or optical disk (fast, cheap, easy) • Standard computer equipment (CD, external hard drive, flash memory) 19 of 42

20. How does GPS solve these problems? Integration with other data (e.g., GIS, inventory) • GPS data are already in digital format • Easily used in association with other digital methods • Inventory systems (e.g., FLIPS, SuperAce) • GIS (direct export from GPS to GIS formats) 20 of 42

21. History of the GPS Cold War origins • Advances in missile technology, 1940s-80s • Advances in missile navigation systems (silo-to-silo attacks) • Submarine missile launchers • Missile launches need precise coordinates • Surfaced submarines need fast locational fix • Fire a missile quickly to avoid being seen Need for locational technology that is fast and precise 21 of 42

22. History of the GPS 22 of 42

23. History of the GPS Evolved out of EM/radio wave locational technologies (WWII onward) TRANSIT (US Navy, Polaris 1964) • Public access, 1967 • Doppler shift of satellite as it moved • Stationary fix, ~every 40 min TIMATION I (USN, 1967) • Coded signals • Precise timing • Ranging based on transit time of signal 23 of 42

24. History of the GPS Navigation Technology Program (USN, USAF, 1973) • Evolved to NAVSTAR GPS • Phase I (1973-78) • Concept validation • Prototype satellites 24 of 42

25. History of the GPS Navigation Technology Program (USN, USAF, 1973) • Evolved to NAVSTAR GPS • Phase II (1978) • Full-scale development • 4 satellites launched • By 1985, 7 operational satellites, ~5 hrs coverage • Current = 32 satellites Others? • GLONASS: Russian Federation (1984-Present) • EU? Japan? Commercial vendors? 25 of 42

26. How does GPS work? Satellite signals • Satellites send coded radio wave signals • Signals are stamped with particular data: • Time of signal generation • Satellite ID number • Radio waves are a form of EM radiation • Light travels at 186,000 mi/s (in a vacuum) Time stamps on signals result in distance measurements 26 of 42

27. end: 0.06 s 12,000 mi How does GPS work? • Distance = rate * time • Radio waves are sent from orbiting satellites • Time stamp on each signal marks the start of the wave • Time of reception marks the end of the wave start: 0.00 s 27 of 42

28. How does GPS work? With the distance from 1 satellite we can locate our position on the surface of a sphere 28 of 42

29. How does GPS work? With the distance from 2 satellites we can locate our position on the intersection of 2 spheres (a circle) 29 of 42

30. How does GPS work? With the distance from 3 satellites we can locate our position on the intersection of 3 spheres (1 of 2 points) 30 of 42

31. How does GPS work? With the distance from 4 satellites we can locate our position on the intersection of 4 spheres (1 point) 31 of 42

32. How does GPS work? The point is (hopfully) located on the surface of the earth 32 of 42

33. What are the benefits of GPS vs. manual survey? Summary: benefits of GPS over other methods • Easy to learn • Fast to use • Automated data recording • Requires less attention to detail • Errors are not additive • No math! 33 of 42

34. Potential GPS error sources Satellite geometry Satellites that are closer result in less accurate measurements 34 of 42

35. Potential GPS error sources Satellite geometry A large spread of satellites makes the most accurate measurements 35 of 42

36. Potential GPS error sources Landscape features Natural & artificial features can intercept signals Mountains, valleys, hills, buildings, tree canopies, etc. 36 of 42

37. Potential GPS error sources Multipath errors Natural & artificial features can reflect signals Multiple “ghost” signals can confound timing: which signal to trust? 37 of 42

38. Other potential GPS problems Equipment can fail, resulting in lost or corrupted data Equipment can be misconfigured, leading to lost or corrupted data, or in the best circumstance, correctable systematic error The DoD could go broke You could go broke (and not be able to buy a GPS unit) 38 of 42

39. Conclusion Land measurement and navigation systems have evolved over time Throughout the “modern” history of measurement, standards have been critical Many different measurement frameworks exist • Metes & bounds • PLSS • UTM • State Plane • … 39 of 42

40. Conclusion Different measurement methods exist • Metes & bounds • Plane surveying • Geodetic surveying • GPS Different data storage systems exist • Maps • Paper or electronic tabular records • GIS 40 of 42

41. Conclusion No measurement framework, method, or storage system is perfect Different methods are the most appropriate in different situations Considerations: • Functional requirements • Cost • Ease of use • Institutional considerations 41 of 42

42. To Infinity and Beyond “The earth has music for those who listen.”— William Shakespeare 42 of 42