Regarding the 3333 tie file:
  • A virtual check-in was created for the begining of the day, because another
    gravity check-in point was used and not visited again. To do this:
      – A Δ from datum value was calculated for the check-in used at the 
        begining of the day:
          ○ station 2223
          ○ datum                          7378.533 mGal
          ○ early day value              – 6001.903 mGal
          ○ Δ                            = 1376.630 mGal.
      – The Δ value was then subtracted from the datum of 3333 to create 
        a virtual check-in at the time of the 2223 check-in:
          ○ station 3333
          ○ datum                          7335.710 mGal
          ○ Δ                            – 1376.630 mGal    
          ○ virtual check-in             = 5959.080 mGal
  • A virtual check-in was also created for the morning camp check-in, in order to
    account for the measurements acquired at L16600W/1750N, which occurred BEFORE
    the occupation of the field check-in 2223 in the morning (and therefore outside
    the scope of the 2 field check-ins):
      — A Δ from datum value was calculated for the morning camp check-in:
        ○ Station 8888
          ○ datum                          7314.300 mGal
          ○ morning camp check-in        – 5937.735 mGal
          ○ Δ                            = 1376.565 mGal.
      – The Δ value was then subtracted from the datum of 3333 to create 
        a virtual check-in at the time of the camp morning check-in:
          ○ station 3333
          ○ datum                          7335.710 mGal
          ○ Δ                            – 1376.565 mGal    
          ○ virtual check-in             = 5959.145 mGal
  • Also, the “official” station reading at L16600W/1800N (which is at the exact
    location of the 2223 check-in) was move from first reading to last reading
    of the occupation, to make it fit in the time range of the field check-ins.

Regarding the 2 xyz files:
  • The DEM covering the whole area is very large, in fact likely too large for
    the field computer used in conjunction with Gravred 3.2 (who is systematically
    loading the whole DEM to the RAM before proceeding to calculations). So in order
    to avoid errors due to lack of memory available, the inner DEM was split into
    2 files of 5.5M points each, and the results from two individual runs are added
    together to create the final xyz containing one unique inner DEM correction value.
  • The final xyz is actually a merger of all days together.