Sunday, June 7, 2009

Flow chart of cadastral survey

This is a flow chart I created for my assistant so that he is to remember when he go for another field work

  1. Step 1 – Input lot bearing and distance into CAD and TSM system (the interest lot and some neighbor lot)
  2. Step 2 – check the precomp plan and ensure the precomp has been approved.
  3. Step 3 – look for the site and boundary with TSM system using GPS
  4. Step 4 – Once find one boundary stone on the site and immediately do sun observation. Bearing can be using compass for compute the station coordinate.
  5. Step 5 – Compute the sun observation and get the true bearing before start traverse.
  6. Step 6 – While traversing the survey lot, try to attempt to find all the old marks on the ground. The purpose is the find a baseline for the survey. Minimum requirement is 2 old marks in position with a sun observation. However, it is advised to get 3 old marks to prove in position.
  7. Step 7 – Try to set station near to the boundary mark but should be 2 meter apart from station. The problem for too close is the surveyor difficult to read the boundary mark)
  8. Step 8 – Ensure the traverse is above first class ( close bearing should less than 1’ 15”)
  9. Step 9- Compute baseline with the existing data. Computation of new should be straight forward. However, PO computation sometimes is a bit troublesome where there are many loops can be computed. Select the best answer either in difference in bearing or distance.
  10. Step 10 – Compute PO adjusted with the acceptable baseline
  11. Step 11 – Compute the missing marks, new marks or refixation from the nearby station.
  12. Step 12- back to site for refix and plant the marks.

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hwhww said...

I would like to ask regarding to step 4, when you just found one old boundary mark, how you make sure that the stone you found at the correct position?

Idham lai said...

dear friend,

TSM system able to tell the actual position when you connect with the GPS. But bear in mind that you need to configurate the map in correct cassini system and the accuracy is within 3-5m.

Same concept with using handheld GPS. You also able to get 3-5m accuracy.