Solution: Coordinate Systems
Problem (5)
Part (a) From the Current Survey Control section, record the following information:
| Datum/Adjustment | NAD 83 (2011) |
| Latitude | 42°57'28.57328" |
| Longitude | 89°37'38.30840" |
Part (b) From the Superseded Survey Control section, record the following information for the NAD 27 datum:
| Latitude | 42°57'28.57000" |
| Longitude | 89°37'37.87000" |
Part (c) Go to NGS NCAT page. Using NCAT, convert the NAD 27 geodetic coordinates to the datum/adjustment in Part (a) and record the reults below.
| Latitude | 42°57′28.57186″ |
| Longitude | 89°37'38.30960" |
Part (d) Do the NCAT geodetic coordinates of Part (c) match the Current Survey Control geodetic coordinates from Part (a)? Why or why not?
No they do not and we don't expect them to be the same.
The geodetic coordinates of Parts (a) and (b) come from the respective datum adjustment. That makes them rigorously defined.
The coordinates in Part (c) are from a transformation which is an approximate model between the two datums. The model is not as good as the original rigorous adjustments.