Altitude QC

Use the Altitude QC option (Geosoft.uxo.gxnet.dll(Geosoft.GX.UXO.UceAltitudeQC;Run)*) to identify and remove data that exceeds the survey altitude threshold.

ClosedExpand to see the locations (menus) where this option is available.

UXO Marine extension:

  • UXO - Marine Grad > QC QA Tools
  • UXO - Marine Mag > QC QA Tools

Altitude QC dialog options

Current database

The name of the current database (read only).

Hovering your mouse over the name will display the full path of the current database.

Script Parameter: AltitudeQC.GDB

Altitude channel

Select the channel that contains the altitude of the sensors above the sea floor.

Script Parameter: AltitudeQC.ALTITUDE_CHANNEL

Despike

 

Check this option to apply a non-linear filter to the output data to remove single-point spikes. Non-linear filters, considered noise spike-rejection filters, are ideal for removing short-wavelength, high-amplitude features from data.

Leave the option unchecked (default) to bypass the "despiking" process.

Script Parameter: AltitudeQC.DESPIKE

Maximum altitude

Specify the maximum threshold (value greater than zero) for the survey altitude. Altitude values exceeding the maximum altitude will be set to dummies ("*") in the output altitude channel. 

Script Parameter: AltitudeQC.MAXIMUM_ALTITUDE

Output altitude channel

Specify the channel to store the output altitude values. The default is altitude channel_Corr.

Script Parameter: AltitudeQC.OUTPUT_ALTITUDECHAN

Create altitude map

Check this option to automatically generate a map of line paths and visualize where the altitudes exceed the maximum threshold. All these deviations (values that are above the acceptable range) are plotted with a single colour (red) on the map.

Script Parameter: AltitudeQC.CREATEMAP


Application Notes

The Altitude QC tool will identify and remove altitude data that exceeds the survey altitude threshold. The output altitude channel will contain dummy (*) values where the threshold is exceeded.

In addition, an altitude deviation flag channel ("Flag_altitude channel") is created and sets the channel values to 1 whenever the altitudes exceed the maximum altitude value (maximum threshold).
This flag or mask channel can be used to blank (dummy) out other data channels as required using either math expressions or the Copy Channel with Mask option found in the Database Tools > Channel Tools menu. You can also use the flag channel along with the symbol plotting tools (e.g., Location Plot under the Map Tools > Symbols menu) to plot where the sensor altitude exceeds the survey threshold on your own custom maps.

*The GX tool will search in the "gx" folder. The GX.Net tools, however, are embedded in the Geosoft.uxo.gxnet.dll located in the bin folder. If running this GX interactively, bypassing the menu, first change the folder to point to the bin folder, then supply the GX.Net tool in the specified format.