Name: Assignment 2 GEOG336-CONTROL & GEODETIC SURVEYING Score: /120 For this portion of the assignment you will be performing some research/calculations dealing with a NGS Horizontal Control Station ‘AIRPORT RESET'

1. Use the NGS website to obtain Control Monument Datasheet. a. Go to the NGS website at www.ngs.noaa.gov i. Browse through the pull-down menus available to familiarize yourself with some of the tools and survey information available from NGS ii. Print Datasheet for monument ‘AIRPORT RESET' 1. Under DATA & IMAGERY menu select SURVEY MARK DATASHEETS. 2. On the lower right side of window that opens under Search By click on text, the left of the two icons to right of Station Name(s) a. Key in AIRPORT RESET as station name and change state to Minnesota, then click SUMBIT b. Highlight station ‘AIRPORT RESET' in the list that opens and click on Get Datasheets. Print the first two pages of the datasheet and provide a copy with assignment report. c. Go back to the SURVEY MARK DATASHEETS webpage and this time click on the Interactive Map and find 'AIRPORT RESET'. In NGS Map search tool (upper left) select NGS Datasheets: PID in pull down menu, and enter PID for ‘AIRPORT RESET' from datasheet and hit enter. The map should zoom in with monument at center of screen (triangle symbol). Print the map screen and provide a copy with assignment report. You could retrieve the datasheet here by clicking on the symbol and selecting Datasheet 'More info'. There are other search criteria such as property address, etc. that can be useful to find control in the area of a project. b. What is the PID (Identification #) for the station, which type of control monument is it (Horizontal, Vertical, both), what accuracy level is it (First, Second, etc.), and which reference ellipsoid are the geodetic coordinates based on? (12 pts.) 2. Using the geodetic latitude for station 'AIRPORT RESET' provided on the datasheet calculate the radii of curvature in the Meridian and Prime Vertical at this station (Use appropriate reference ellipsoid parameters from text on page 542). The Geodetic Azimuth from station 'AIRPORT RESET' to station ‘AIRPORT AZ MK' is listed on the datasheet as 232°46'48.2", verify this azimuth on your datasheet and calculate the radius of curvature of the 'Great Circle' in the direction between these two stations. Are the three of these calculated radii values the same? Why or why not? (28 pts.) 3. The LaPlace correction at station ‘AIRPORT RESET' is provided on the datasheet. Use DEFLEC18 to determine the components xi and eta which make up this deflection of vertical, and verify the LaPlace correction listed on datasheet. (DEFLEC18 calculation software can be found from the main NGS website in GEOID Models area (click to open in lower left), then click on GEOID18, click on DEFLEC18 in listing that loads on the left, then click on DEFLEC18 Interactive Computations in menus to the left) Key in Latitude and Longitude, Click on Perform... and printout the DEFLEC18 output and provide it in your report. Calculate the Astronomic Azimuth between station 'AIRPORT RESET' and station ‘AIRPORT AZ MK' from the Geodetic Azimuth given on datasheet, assuming Geodetic Azimuth = LaPlace Azimuth. (20 pts.) Perform the following calculations utilizing the formulas for Convergence of Meridians, Parallel of Latitude Offsets, and distances between control points. The radius of Earth of 20,906,000 feet will be used for calculations. The control points and associated geodetic coordinates (NAD83(1996)) utilized will be the following: Control Point AIRPORT RESET 3408 D Latitude 45°34'49.75247"N 45°21'24.19959"N Longitude 094°10'37.13349"W 094°45'46.78573"W 4. Calculate the Meridian Convergence between the control points utilizing both the rigorous and short line approximation methods. Show all intermediate value calculations (om, A, Aλ). What is the value of the difference between the calculated convergence using the two methods? (20pts.) 5. Solving one of the short line approximation equations for Aa from class (Aa=tan(0m)) we get that d = R R*Δα tan(Pm) Utilize this equation to calculate the East- West distance between the control points using both Meridian Convergence values calculated in #4 above and then calculate the difference between the distances. Is this difference significant? Explain. (20pts.) 6. Using the geodetic latitude of each control point individually calculate offsets for 1 mile, 5 miles, and 10 miles along the Great Circle to the parallel of latitude. Compare the differences between the calculated offsets at each distance for the two latitudes. Are these differences significant? Explain. (20pts.)