Despike Channel

Use the Despike Channel option (geogxnet.dll(Geosoft.GX.Field.DespikeChannel;Run)*), from the Database Tools > Filters menu, to remove undesirable high amplitude spikes from the data.

Despike Channel dialog options

Input channel

The input channel to filter.

Script Parameter: DESPIKE.INPUT

Output channel

The output filtered channel name. The first time through, the default is set to the name of the input channel appended by _despike. However, you can override the default.

  • If the input channel is an array, the output channel will be created as an array channel of the same size as the input channel. If the output array channel exists, the output channel size must match the size of the input channel.

    • Script Parameter: DESPIKE.OUTPUT

    Time channel

    The time channel. The channel must be in units of hours and is used to figure out the number of records covering the specified number of seconds.

  • Pre-populated if a "Time" channel exists in the database.

    • Script Parameter: DESPIKE.TIME_CHANNEL

    Over number of seconds

    The width of the spike in seconds. The time channel is then used to figure out the number of records covering this number of seconds.

    Script Parameter: DESPIKE.NUMSECONDS

    Application Notes

    The drop outs and/or spikes usually have a high amplitude and short time span. This filter helps remove spikes of this nature. If the channel to filter is an array channel, the filter is applied to each element of the array.

    It is crucial to have a time channel in the database: it is used to figure out the time sampling rate and equate it to the width of the noise to remove.

    *The GX tool will search in the "...\Geosoft\Desktop Applications \gx" folder. The GX.Net tools, however, are embedded in the geogxnet.dll located in the "...\Geosoft\Desktop Applications \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.

    References

    • H. Naudy and H. Dreyer, "Essai de filtrage nonlineare appliqué aux profils aéromagnétiques", Geophysical Prospecting, vol. 16, no. 2 (1968), pp. 171-178