Flight Deviation (Batch QC Parameters)

Use the Flight Deviation tab (QCPATH GX) to perform quality control on airborne flight paths.

Flight deviation tab options

Ideal path database	Select the Geosoft database that contains the ideal flight path data. This is a required field. Script Parameter: QCPATH.GDB
Maximum deviation	Specify the maximum deviation. Script Parameter: QCPATH.MAXDEV
Allowed separation	Specify the allowed separation. Script Parameter: QCPATH.ALLDEV
Over a distance of	Specify the "over a distance of" parameter such that, if the Allowed separation value (see above) is exceeded for this specified distance then the line will be flagged as out of survey specification. Script Parameter: QCPATH.DIST

Application Notes

Current database

This GX assumes that the current database is the one containing the actual survey data. The database is called the survey database. If you wish to process a different database, you may browse to add it to the project or select one from the workspace list.

Database containing the ideal line path

This is the database created when a proposal is made during planning stage. It is called the ideal-line-path database. If you used this Airborne QC package (using the Create a Survey Plan menu option) to create the proposed survey plan, you should have such a database available. Otherwise, you need to prepare a XYZ file containing the proposed survey plan data and then import the file into a new database.

Note that the selected lines in the survey database must have matching line numbers in the ideal-line-path database. This means that their line types, line numbers and line versions match. If a selected line(s) exists in the survey database but not in the ideal-line-path database, a message will be displayed at the end of the dialog displaying the number of that line(s).

The exception to the above rule is with regard to re-flights. The line number of re-flights is generally labelled using the number of the original line plus 1. Subsequent re-flights on the same line will be incremented by 1, to a maximum of 9. For example the first re-flight for line 11230 is labelled 11231, the 2nd re-flight is labelled 11232. The re-flight line numbers need not exist in the ideal-line-path database. As in the previous example, re-flights 11231 and 11232 will be tested against the line number 11230 in the ideal-line-path database.

Ideal lines are straight lines defined by two separate points. Therefore, this dialog uses only the first and second (X, Y) coordinates to define the straight line. If there are dummy values in those two pairs of coordinates, a straight line cannot be defined and the quality control test will not be carried out. The warning message displayed if this occurs, will report the line number.

You can use line edit tool to change the line numbers (type, number and version) in the ideal line path database. You can also use the insert re-flight line tool to insert a new line into the ideal-line-path database.

Quality Control Specifications and Indicators

This dialog enables two separate specifications to be tested to determine whether the airplane flight line paths are acceptable or not.

1)	At each reading location, the deviation of the flight lines from the ideal flight path must be less than the Maximum deviation specified.
2)	The deviation of the flight lines from the ideal flight path may be greater than the specified deviation for a distance less than the specified distance.

You can apply one or both of these specification tests. To disable a test leave the blank empty.

This dialog creates a flag channel called Flag_Path in the current database. This channel contains numbers from -3 to 3 inclusive to indicate the result of the quality control test in terms of flight line path.

 Indicator and Description

Calculation of Distances

When the specification of deviation over a specified distance is tested, the cumulative distance along the actual survey locations is used instead of the distance along the ideal line path.