- Write a description of how to convert from location data given in degrees, minutes and seconds into decimal degrees.
- Use the method you described above to express the following in decimal degrees:
- 31° 31' 19.0"
- 97° 12' 9.5"
- 138° 53' 47.2"
- 16° 38' 52.8"
- 31° 31' 19.0"
- What is a good approach to the problem of defining how many decimal places to the right of the decimal point are warranted if the input is given in minutes, or seconds, or tenths of seconds, or ...?
- How many decimal places to the right of the decimal point are warranted if the input data are given to the tenth of a second?
Today's date: _____________________ and declination: _______________________________
- Using the simplifying assumption that Earth is a sphere, what is the corresponding distance (in meters) for a 1° change in latitude?
Latitude conversion factor: 1° of latitude is equal to approximately _______________ meters
- Write a method/formula for finding the length of 1° of longitude at a given latitude, assuming a spherical Earth. Hints: Assume a unit radius for Earth, and take note of the fact that the length of 1° of longitude at latitude 0° (the equator) is equal to the length of 1° of latitude, but that the length of 1° of longitude is zero (0, nil, nothing, nada) at the poles (i.e., at ±90° latitude).
- Use the method you just described to find the change in distance (in meters) for a 1° change in longitude at a latitude of N31°31'19.0".
- Record the location data that you collected on the field trip to the area around the Lehigh quarry near Waco in the table below:
Location Latitude in decimal degrees Longitude in decimal degrees Horizontal uncertainty in meters Stop 1 __________________ __________________ __________________ Stop 2 __________________ __________________ __________________ Stop 3 __________________ __________________ __________________
- Find the latitude half way between the greatest and least latitude among these three points.
middle latitude: ____________________ - Use the middle latitude to define the conversion factor from degrees of longitude into meters.
Local longitudinal conversion factor: 1° of longitude = __________________ meters - Find the farthest south latitude among these three points.
south latitude: ____________________ - Find the farthest north latitude among these three points.
north latitude: ____________________ - Find the farthest east longitude among these three points.
east longitude: ____________________ - Find the farthest west longitude among these three points.
west longitude: ____________________ - The origin, where the new coordinates are defined a 0 meters north and 0 meters east, is located just to the southwest of the cluster of 3 locations we visited. The y coordinate at the "south lat" identified above is +500 meters, and the x coordinate of the "west longitude" identified above is +500 meters. Determine the difference in latitude from the "south lat" and the difference in longitude from the "west longitude" for each of the three sites:
Location Change in latitude in decimal degrees Change in longitude in decimal degrees Stop 1 __________________ __________________ Stop 2 __________________ __________________ Stop 3 __________________ __________________
- Use the latitude conversion factor and the local longitude conversion factor for this area, and the data computed in the last step, to define the site locations in your new local coordinate system in meters:
Location x coordinate (varies E-W) y coordinate (varies N-S) Stop 1 __________________ __________________ Stop 2 __________________ __________________ Stop 3 __________________ __________________
- Find the three sites within the red boxes on the aerial photograph shown below (http://bearspace.baylor.edu/Vince_Cronin/www/StructGeol/QuarryAirPhoto72.jpg)
- Given this aerial photograph and the coordinates of the three sites, expressed in meters, write a description of how you will determine the scale of this photograph.
- What is the scale of the aerial photograph? Answer: the aerial photograph is at a scale of 1:____________________, or 1 cm on the photograph is equivalent to ____________ cm on the ground.
- Given this aerial photograph and the coordinates of the three sites, expressed in meters, write a description of how you will determine the orientation of this photograph relative to north.
- What is the orientation of the left and right sides of the aerial photograph, assuming them to be parallel to each other? Answer: the sides of the aerial photograph are parallel to a line trending _______________°.
- Draw a set of lines oriented north-south and east-west through the three sites.
- List the data you collected in the field, finding the azimuth of the cooling tower from each of the three sites:
Location Azimuth to cooling tower Stop 1 __________________° Stop 2 __________________° Stop 3 __________________°
- Using a protractor and the field observations above, carefully draw lines on the topo map from each of the three sites to locate the water tower by triangulation.