GISC3325 Spring 2011 Final Exam

Transcription

1 GISC3325 Spring 2011 Final Exam Name: Carefully read each question. Identify the important elements and the question being asked. Show your work for partial credit. No credit for undocumented wrong answers. This is an individual effort no help from classmates or others. 1. Why does a dynamic height differ from an NAVD 88 orthometric height? (3 pts) 2. Why is NADCON used to transform between NAD 27 and NAD 83(1986) and NOT the program HTDP? (3 pts) 3. Why are astronomic and geodetic azimuths different? (3 pts). 4. Which geoid model should be used when transforming from NAD83 ellipsoid height into an NAVD88 orthometric height? Why this model? (2 pts) 5. What differentiates a hybrid geoid like GEOID09 from a gravimetric one like USGG 09? (3 pts) 6. What national horizontal datum was replaced by NAD 83 (1986)? (2 pts) 7. Compute the radius of curvature in the prime vertical for Latitude North 36deg. Compute values in both GRS 80 and Clarke (8 pts)

2 8. Describe how to convert an astronomic azimuth into a plane azimuth? (3 pts) 9. What does the OPUS static solution peak-to-peak error represent? (3 pts) _ 10. Our client wants us to position a point, HARASS, that cannot be occupied using GPS. He has performed reconnaissance and found a suitable NGS-published monument for our use. He also found a local control point, BLAH, with state plane coordinates that is visible from the NGS-published monument. The published monument is S1, its PID is TT0658. BLAH, of unknown provenance, is an unmarked PK nail and washer. Our client provides us the following state plane coordinates for BLAH. The coordinates are: N845, and E528, Coordinates are in meters and were taken from a field book. To verify that the PK nail and washer is the correct monument we make a Polaris observation at S1 to BLAH. The Polaris azimuth is: 320d 36m 35.0s. a. Does our Polaris azimuth agree with the appropriate inverse azimuth using a tolerance of 5 seconds? Yes or No (circle answer) (1 pt) b. What is the difference in seconds between the Polaris azimuth and appropriate inverse azimuth?. (3 pts) Assuming we have correctly identified BLAH, we make the following observations: Horizontal angle at S1 from BLAH to HARASS: 132d 24m 03.1s; Mark-to-mark distance: 12, meters Zenith angle: 89d 34m 54.6s. The client wants the following values for monument HARASS: c. NAD 83 (2007) geodetic coordinates: latitude, longitude and ellipsoid height report in degrees, minutes and seconds using 5-decimal place seconds. d. State plane coordinates in meters to nearest millimeter. e. NAVD88 height in meters to nearest millimeter. f. Elevation factor at station using earth radius ( R)=6,388,365m to 8-decimal places. g. Geopotential number at this station. Use NAVD88 modelled gravity. h. Dynamic height of the station in meters to nearest millimeter. I. ITRF 2005 epoch 2 May 2011 geodetic coordinates for the station.

3 Describe how you solve the problem. Be sure to address each step needed to solve the problem: (You may need more or fewer steps). Graded separately from numeric results. (10 pts) Provide numeric results providing all required information: c. NAD 83 (2007) geodetic coordinates report in degrees, minutes and seconds using 5-decimal place seconds: (10 pts) latitude longitude ellipsoid height d. State plane coordinates in meters to nearest millimeter. (2 pts) N: E: e. NAVD88 height in meters to nearest millimeter. (2 pts) f. Elevation factor at station using earth radius ( R)=6,388,365m to 8-decimal places. EF: (3 pts) g.geopotential number at this station. Use NAVD88 modelled gravity. C: _ (5 pts) h. Dynamic height of the station in meters to nearest millimeter. H dyn (5 pts) I. ITRF 2005 epoch 2 May 2011 geodetic coordinates for the station. (5 pts) Latitude: Longitude: Ellipsoid height:

4 11. Leveling was performed between S1 (used above) and the closest NGS-published benchmark, N 102, with a field difference in height of meters. The distance between monuments is 2.0 kilometers. Does the height difference meet FGCS leveling standards for section misclosure at the first-order class II standard? (2 pts) Yes or No (circle answer) 12. Examining the data sheet for S1 used above, we see that the following heights are provided: NAD 83 ellipsoid(h), NAVD 88 orthometric (H), and the hybrid geoid model (geoid ellipsoid separation) GEOID 2009 (N). (8 pts) a. Provide an equation showing how the three heights are related: b. What is the algebraic sum of the values using the equation above? c. Ideally what should the sum be? d. Why don't they sum up to the ideal value?. 13. I have been contracted to consult on a level project in Ouray County, Colorado. The surveyors ran check levels between NGS-published benchmarks from C 439 to B 439. Their field determined difference in height was meters. The distance between the benchmarks is 1.9 kilometers. They think this does not meet second-order class I specifications. I say it does. Why am I right? (5 pts) 14. Performing a height modernization survey using GPS using NOAA Technical Memorandum NOS NGS-59, what the three basic rules? (2 pts) What is the problem constrained adjustments discussed in the article by Dr. Charles Schwarz? (7 pts)

5 Computation work sheet (will be reviewed for partial credit for wrong answers).