TerraMatch found “0 tie lines”


When searching for tie lines in TerraMatch the “found 0 tie lines” message appears quite quickly.


Double check that your trajectories and data align, and that the settings match your data.

  1. Verify that the flight line number of the trajectories corresponds to the flight line number assigned to the points. Draw the trajectories into MicroStation and display the points by Flightline to see if the colors are in sync. Identify a point and a corresponding trajectory to ensure they numerically align.
  2. Verify that the timestamps of the trajectories are the same as the points. For example, if the trajectories are in Adjusted GPS Standard Time, then the points must be as well. Verify that the timestamp of a trajectory corresponds with the timestamp of a point in the vicinity.
  3. If you’re assigning and using scanner numbers to represent the different channels, then verify that the trajectories have been assigned to a scanner system that has been defined to contain the appropriately numbered scanners.
  4. Verify there is overlap between the flight lines.
  5. Verify that the classes being searched exist within your dataset, and also in each of the overlapping flight lines.
  6. Check that your maximum XY, and maximum Z settings on the tie line dialog are slightly larger than the observed maximum values that you measured.
  7. Verify that the fit tolerance is appropriate for your data set. Most mobile systems should use 0.03m, and most current generation airborne systems should be 0.08m.
  8. Verify that the depth of the tie line being searched is appropriately wide enough to encompass data from a minimum of two overlapping flight lines but not too wide as to contain data that should not align.
  9. Verify the length of the tie line being searched is long enough to contain a minimum of 4-5 points.

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