Following examples are calculated with BestNetwork.
Task
Calculate new coordinates for a boundary in a forest. It is not possible to use GNSS. The approach is to traverse with a total station. The yellow points are unknown. For these points new coordinates have to be calculated.
I have the choice of using old measurements or measure a new traverse. What is the difference in accuracy. What do I gain with new measurement? Here the picture of the two equipments. For both choice I set an accuracy of 10 mm for known points.
Traverse with new total station 2016
Parameters:
- distance 2 mm + 2ppm
- direction 0.5mgon
- centring error 1mm
Traverse with DK-RT 1930
Parameters:
- distance 10 mm + 100ppm
- direction 1.5mgon
- centring error 10mm
Result Traverse with new Total Station
- 8 mm
Result Traverse with DK-RT 1930
- 24 mm
24 mm is not bad. Consequently I us old measurements instead of going out into the forest and measure the traverse again. What would you do?
Thoughts
I wish I had found this sooner. I was tasked with re-surveying two golf courses, one that I'd surveyed 12 years ago. I decided not to re-survey the points, but only find the corners and flag them. I did check some with GPS. They were OK. I would have felt much better had I read your post then.
Thanks,
Keith