Statistics of Survey Data

Use the Statistics of Survey Data option (QCEXTSTATS GX) from the Airborne QC menu to produce a statistics summary report of a selected list of channels for all selected lines in the current database.

Statistics of Survey Data dialog options

Channels to use	Choose the channels to calculate statistics from. The options are: Choose from list - opens the channel selection tool to select the channels to be processed. Displayed channels (default) All channels Script Parameter: QCEXTSTATS.USECHAN [0 - all channels; 1- displayed channels; 2- selected channels]
Output file name for summary report	Specify the name of the summary report file to be created (ASCII format). Defaults to "<database>_stats.txt". Script Parameter: QCEXTSTATS.FILE
Display channel(s) histogram	Select Yes to display a histogram for all the processed channels. Script Parameter: QCEXTSTATS.HIST [0 - No; 1 - Yes]

Application Notes

The statistics will be calculated for the lines/groups selected in the database.

The statistics for the X and Y channels are always included in the statistics summary if they are present in the database. The statistics calculated for the X and Y channels include the minimum and maximum values, total distance, and the number of valid points. They are calculated for each line separately and for the entire selected data set.

The statistics calculated for each additional channel include the minimum value, the maximum value, the arithmetic mean, the median, the mode, the standard deviation, the standard deviation of the first and fourth differences, the number of valid points, and the number of dummy values. These are calculated for each line separately and for the entire selected data set.

Notes:

• For channels of string data type, only the channel names will be output to the summary file, no statistics can be calculated.
• The calculation of statistics is based on the raw data of each channel. If two channels of a given line in a database have a different fiducial start and increment, the number of elements used in the calculation in each channel may differ. These channels are recognized by the red underlining of the channel name in the database.
• For array channels, the statistics for the entire array are reported followed by the statistics for each individual array element.
• The mode statistics is useful to check the levelling of the data, while the standard deviation of the first and fourth differences can be inspected to identify lines with excessive noise.

Scripting

To run this GX within a CMD (Command Prompt) script, the following parameters should have values specified: