Determine Model Coherence Anomalies

Use the Determine Model Coherence Anomalies option, (Geosoft.uxo.gxnet.dll(Geosoft.GX.UXO.UxaModelCoherenceAnomalies;Run)*), to identify the approximate locations of targets from dynamic data.
A series of data-chips are extracted from the located survey data and a simple, single dipole model calculated. If a particular data-chip of data produces a good model fit, as measured by the model coherence (UXA_FIT_COH), we can assume a buried source is nearby. A grid of the coherence is calculated and can then be used to identify potential target locations.

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

UX-Analyze extension:

  • AGC Dynamic Data > Coherence Anomaly
  • AGC Expert User > Dynamic Data Prep and QC

Determine Model Coherence Anomalies dialog options

Database prefix

Select the sensor (data) database prefix.

Script Parameter: UXANALYZE.DYN_DBPREFIX

Lines to process from located database

Select the lines, which can be Selected lines or All lines.

Script Parameter: UXANALYZE.LINES_TO_PROCESS

Sensor channel suffix - leveled

Specify the sensor channel suffix.

Script Parameter: UXANALYZE.SENCHAN_SUFFIX

Gates

Select the low and high time gates from the list, which limit the range of data used when modelling the data.

Default, low gate: gate value based on UXA_GateFirstValidTime channel

Default, high gate: the maximum gate number

Script Parameters:

  • UXANALYZE.DYN_LOGATE
  • UXANALYZE.DYN_HIGATE

Pitch channel

Select the pitch channel from the list of existing database channels. The default value is UXA_PITCH_FILT.

Script Parameter:UXANALYZE.PITCH

Roll channel

Select the roll channel from the list of existing database channels. The default value is UXA_ROLL_FILT.

Script Parameter:UXANALYZE.ROLL

Heading channel

Select the heading channel from the list of existing database channels. The default value is UXA_COG.

Script Parameter:UXANALYZE.YAW

Coherence Anomaly

Mesh cell size (m)

Enter the cell size for the coherence mesh that covers the survey area. It should be chosen to properly define the coherence anomalies and the typical range is between 0.1 and 0.5 metres.

Default is 0.1 metre.

Script Parameter:UXANALYZE.COHERENCE_ANOMALY_MESH_CELL_SIZE

Data chip cross-line dimension (m)

Enter the data chip cross-line dimension.

Default value is 1.6.

Script Parameter: UXANALYZE.DATACHIP_CROSS_LINE

Data chip along-line dimension (m)

Enter the data chip along-line dimension.

Default value is 1.2.

Script Parameter: UXANALYZE.DATACHIP_ALONG_LINE

Probable source depth (m)

Enter the probable source depth.

Default value is 0.4.

Script Parameter: UXANALYZE.PROBABLE_SOURCE_DEPTH

Survey line direction (deg)

Enter the survey line direction in degrees, which is between -180 and 180 and measured from the north.

The Calculate button button will cause the default direction to be calculated and displayed, and it can be modified to an appropriate value if desired.

Script Parameter: UXANALYZE.DATACHIP_LINE_DIRECTION

File name suffix

Enter the optional file name suffix, which will be added to the default names for coherence anomaly database and grid:

Coherence anomaly database: [PREFIX]_[DATATYPE]_CohAnomaly_[SUFFIX].gdb

Coherence anomaly grid: [PREFIX]_[DATATYPE]_CohAnomaly_[SUFFIX].grd

Default value is Blank.

Script Parameter: UXANALYZE.COHERENCE_ANOMALY_SUFFIX

[Adv. Grid Parameters]

When selected the Grid Parameters dialog is displayed that enables the user to set the gridding parameters for this GX.

*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.