Lake Nokomis survey
Lake Nokomis survey is a theodolite survey across Lake Nokomis
in Minneapolis on 31 October 2026. An AdirPro instrument stood on the north shore. A prism on a pole was set on the far shore. The field book, the weather station, and the phone GPS screens are the record.
Participants
- MCToon
- Dawn
- Schedzy
- Boat Landing
- Two fans of the channel. Their names are not on this page.
Time
The Sharp weather-station clock was set to Pacific. It runs two hours behind Minneapolis.
The iPhone EXIF offset is -05:00. On the 08:13 photo the GPS clock is 13:13:29 UTC and the camera clock is 08:13:29. That is the same five-hour gap, so the EXIF clock is already Central Daylight Time. The correct local time for each photo below is the EXIF time, not the time on the station.
The outdoor channel on the station is dashes wherever that part of the display can be read. The pressure stays on 29.32 inHg. The channel labeled indoor is the sensor in the unit, and the unit was sitting outside.
Stations
Coordinates are WGS84 from a phone screen, 3D fix. The large 0 on that app is not a surveyed elevation. iPhone altitudes in the file tags are phone GPS, not a level.
| Place | Latitude | Longitude | Decimal degrees |
|---|---|---|---|
| Instrument | 44°54'52.238" N | 93°14'12.888" W | 44.91451056, -93.23691333 |
| Site 1 | 44°54'42.432" N | 93°14'07.526" W | 44.91178667, -93.23542389 |
| Site 2 | 44°54'28.787" N | 93°14'16.559" W | 44.90799639, -93.23793306 |
| Site 3 | 44°54'21.130" N | 93°14'25.218" W | 44.90586944, -93.24033833 |
| Site 4 | 44°54'08.434" N | 93°14'44.928" W | 44.90234278, -93.24581333 |
| Site 5 | no GPS screen in this set |
Straight-line distance from the instrument screen fix, on a sphere of radius 6,371 km:
| Site | Distance | Bearing from true north |
|---|---|---|
| 1 | 325 m | 159° |
| 2 | 729 m | 186° |
| 3 | 998 m | 196° |
| 4 | 1524 m | 207° |
The field book labels stations I, II, III, and IV. The photo sets are sites 1 through 5. Nothing in the frames says which station number is which site. There is no Station V page.
Theodolite and target
Field notes
Photographed at 10:10 CDT, after the setups. One line on Station I and one line on Station III are struck through. The seconds on the last horizontal reading of Station III are the hardest digits on that page.
Note: Station 1 readings are unreliable, the theodolite telescope was out of focus.
| Order | Angle |
|---|---|
| 1 | 89°59'48" |
| struck | 270°00'06" |
| 2 | 270°00'07" |
| 3 | 89°59'46" |
| 4 | 270°00'08" |
| 5 | 89°59'46" |
| 6 | 269°59'55" |
| Order | Angle |
|---|---|
| 1 | 90°00'16" |
| 2 | 269°59'17" |
| 3 | 90°00'10" |
| 4 | 269°59'40" |
| 5 | 90°00'08" |
| 6 | 269°59'32" |
| Order | Angle |
|---|---|
| struck | 90°00'04" |
| 1 | 90°00'33" |
| 2 | 269°59'14" |
| 3 | 90°00'26" |
| 4 | 269°59'06" |
| 5 | 90°00'23" |
| 6 | 269°59'36" |
| Line | Angle |
|---|---|
| 1 | 90°00'35" |
| 2 | 269°59'16" |
| 3 | 90°00'37" |
| 4 | 269°59'10" |
| 5 | 90°00'29" |
| 6 | 269°59'10" |
| 7 | 90°00'40" |
| 8 | 269°59'17" |
| 9 | 90°00'29" |
| 10 | 269°59'17" |
Collimation and averages
| Line | Face Left | Face Right | ArcSeconds of Drop |
|---|---|---|---|
| 1 | 90°00'35" | 269°59'16" | 39.5 |
| 2 | 90°00'37" | 269°59'10" | 43.5 |
| 3 | 90°00'29" | 269°59'10" | 39.5 |
| 4 | 90°00'40" | 269°59'17" | 41.5 |
| 5 | 90°00'29" | 269°59'17" | 36.0 |
| Average | 40.0 |
Temperature
Each caption gives the correct local time from the iPhone EXIF, then the Pacific time on the station when that clock can be read.
