Create Data and Model Themes

Model Quality is used to create a number of different point theme quality control maps of the data processing and inversions. Such maps are very useful for inversion evaluation and data reprocessing. They can also be used to showcase the quality of the final data processing and inversion result.

To create a Model Quality node first select a model selection or an inversion node in the Workspace Explorer and click Model Quality on the Visualization ribbon. If done from an inversion node or the data node, one will need to confirm the dataset and inversion (SelectDataTypeAndNodes). Next one is prompted for the name of the new node.

When all the models have been loaded, the Create Data and Model Themes window opens and one is presented with a large number of possible visualization themes grouped over several tabsheets. For each theme, on each tabsheet one can:

• Check the box for the visualization theme so that the theme will be made.
   
• Edit the Point Size and Symbol to use for the theme.
   
• Edit the Color Scale to use for the theme. Use the ... button to open the editor (ShowEditColorScale).
   
• Edit the Auto Scale to use for the color scale. There are three options here:
   
  • No means that the color scale is used as it is.
     
  • Linear means that the color intervals will be linearly distributed between the minimum and maximum data value of the theme.
     
  • Logarthmic means that the color intervals will be logarthmically distrubuted between the decades closest to the minimum and maximum data value of the theme.
     
• Select the Layers, Channels and/or Gates that should be visualized. Each selection will create its own theme. There are three different types of selections here:
   
  • Layers, one theme will be made for each of the selected layers.
     
  • Channels, one theme will be made for each of the selected channels. The All selection is across all channels.
     
  • Gates, one theme will be made for each of the selected gates. If there are more than one channel, there is a list of gates for each channel. For instance, it is possible with a Gates selection to create visualization of gates 5-10 of channel 1 and 10-15 of channel 2 for at total of 12 visualization themes.
    
    Until release 6.8 the gate numbers here were not the import gate numbers, it was the gates in use counted from the first to last gates. In the unusual case where some soundings have had early gates removed, gate 1 would not be the same time gate everywhere. For any inversion done in release 6.8 or later the actual gate numbers are used.

Note that Auto Scale if set, is done separately for each visualization.

All the possible visualization themes for each tab are listed below with a few comments added about the more useful visualizations.

The different visualizations and in some cases whole tabs of visualization (like the ones for IP and System) will not appear if it doesn’t make sense for the used data type. 

Layers

The Layers tab include all the layers related visualization options:

• Resistivity Start: Resistivity of the starting model, [Ohm-m].
   
• Resistivity Inverted: Resistivity from the inversion, [Ohm-m].
   
• Resistivity Factor: Resistivity Start divided by Resistivity Inverted, [factor].
   
• Resist. a-priori STD: Resistivity a-priori STD, [factor].
   
• Conductivity Start: Conductivity of the starting model, [mS/m].
   
• Conductivity Inverted: Conductivity from the inversion, [mS/m].
   
• Conductivity Factor: Conductivity Start divided by Conductivity Inverted, [factor].
   
• Conduct. a-priori STD: Conductivity a-priori STD, [factor].
   
• Thickness Start: Layer thickness of the starting model, [m].
   
• Thickness Inverted: Layer thickness from the inversion, [m].
   
• Thickness Difference: Thickness Inverted minus Thickness Start, [m].
   
• Thick. a-priori STD: Thickness a-priori STD, [factor].
   
• Depth Start: Depth to bottom of layer, of the starting model, [m].
   
• Depth Inverted: Depth to bottom of layer, from the inversion, [m].
   
• Depth Difference: Depth Inverted minus Depth Start, [m].
   
• Depth a-priori STD: Depth a-priori STD, [factor].

Some of the more useful visualizations here are Resistivity Start and Resistivity Inverted. Resistivity Start is particular useful when one has used resistivity apriori in the inversions.

IP

The IP tab include all the layers related IP parameter visualization options:

• Chargeability/Phi Start: Chargeability of the starting model, [mV/V].
   
• Chargeability/Phi Inverted: Chargeability from the inversion, [mV/V].
   
• Chargeability/Phi Factor: Chargeability Start divided by Resistivity Inverted, [factor].
   
• Chargeability/Phi a-priori STD: Chargeability a-priori STD, [factor].
  
   
• TauRho/TauPhi Start: Tau of the starting model, [sec].
   
• TauRho/TauPhi Inverted: Tau from the inversion, [sec].
   
• TauRho/TauPhi Factor: Tau Start divided by Conductivity Inverted, [factor].
   
• TauRho/TauPhi a-priori STD: Tau a-priori STD, [factor].
  
   
• C Start: C-parameter of the starting model.
   
• C Inverted: C-parameter from the inversion.
   
• C Difference: C-parameter Inverted minus C-parameter Start.
   
• C a-priori STD: C-parameter a-priori STD. [factor]
   

STD

The STD tab include all the standard deviation related visualization options:

• Resistivity STD: The standard deviation on the resistivity, [factor].
   
• Conductivity STD: The standard deviation on the conductivity, [factor].
   
• Chargeability STD: The standard deviation on chargeability, [factor].
   
• TauRho/TauPhi STD: The standard deviation on tau, [factor].
   
• C STD: The standard deviation on C- parameter, [factor].
   
• Thickness STD: The standard deviation on the thickness, [factor].
   
• Depth STD: The standard deviation on the depth, [factor].
   
• Data STD: The standard deviation on the data, [factor].
   
• Altitude STD: Standard deviation on the height, [factor].
   

Data

The Data tab include all the data related visualization options:

• Number of Data Points: Number of data points.
   
• Data Residual: Data residuals (data fit) for the individual models, [normalized with data STD]. A data value of 1 corresponds to a fit to the data STD for the sounding.
   
• Total Residual: Residual of the inverted sections (Inc. prior constraints), [normalized with data STD]. A data value of 1 corresponds to a fit to the data STD for the sounding.
   
• Relative Residual: Relative residual of each data point (gate). Calculated as (forward data-measured data)/STD². So how well did a particular gate fit.
   
• Max. Rel. Residual: Maximum relative residual. So how badly did the worst fitting gate fit.
   
• Max. Rel. Res. Gate: Maximum relative residual gate number. What is the gate number of the worst fitting gate. These are the same gate numbers as used in the selection.
   
• Last Data: The time stamp of the last data point.
   
• Channel Number: Number of channels included.
   
• Data: Input data for the selected channel and gate combination, [type dependent] (dB/dt would for example be [V/(A*m⁴)]).
   
• Data Inverted: Forward data from inversion result for the selected channel and gate combination, [type dependent] (dB/dt would for example be [V/(A*m⁴)]).
   
• Data Difference.: Data minus forward data from the inversion result for the selected channel and gate combination, [type dependent] (dB/dt would for example be [V/(A*m⁴)]).
   

Some of the more useful visualizations here are Number of Data Points, Data Residual and Channel Number. Total Residual has lost most of its use now that it is possible to invert everything in one big section or cell. For the Channel Number theme, it is important to use the right color scale and not to auto scale it. For a two channel system, the default color scale channels.awc is red when only the low moment is present, blue when only the high moment is present, and green when both moments are present in each model.
 

Altitude

The Altitude tab include all the altitude related visualization options:

• Topography: GPS elevation minus altitude from inversion results. Note: This topography model may only be a rough estimate, depending on the precision on the GPS elevation, [m].
   
• Altitude: Input height of airborne instruments, [m].
   
• Altitude Inverted: Height of airborne instruments from the inversion, [m].
   
• Altitude Difference: Altitude Inverted minus Altitude, [m].

Topography can be useful, but it is not a replacement themes for a proper DEM. All the other visualizations can be quite useful when looking at inversion results.
 

DOI

The DOI tab include all the Depth of Investigation related visualization options:

• DOI Conservative: Conservative Depth of Investigation from the inversion, [m].
   
• DOI Standard: Standard Depth of Investigation from the inversion, [m].
   
• DOI Conservative as Elev.: Conservative Depth of Investigation from the inversion. Transformed to elevation values, [m].
   
• DOI Standard as Elev.: Standard Depth of Investigation from the inversion. Transformed to elevation values, [m].
   
• Res. at DOI Conservative: The resistivity of the model at the DOI Conservative cutoff, [ohm-m].
   
• Res. at DOI Standard:The resistivity of the model at the DOI Standard cutoff, [ohm-m].

Here the different DOI values in depth and elevation are the most useful.
 

IP DOI

The IP DOI tab include all the Depth of Investigation related IP parameter visualization options, so the same as for resistivity, just with the IP parameters:

• Chargeability/Phi DOI Conservative: Conservative Depth of Investigation from the inversion, [m].
   
• Chargeability/Phi DOI Standard: Standard Depth of Investigation from the inversion, [m].
   
• Chargeability/Phi DOI Conservative as Elev.: Conservative Depth of Investigation from the inversion. Transformed to elevation values, [m].
   
• Chargeability/Phi DOI Standard as Elev.: Standard Depth of Investigation from the inversion. Transformed to elevation values, [m].
   
• Chargeability/Phi at DOI Conservative: The Chargeability of the model at the DOI Conservative cutoff, [mV/V].
   
• Chargeability/Phi at DOI Standard:The Chargeability of the model at the DOI Standard cutoff, [mV/V].
  
   
• TauRho/TauPhi DOI Conservative: Conservative Depth of Investigation from the inversion, [m].
   
• TauRho/TauPhi DOI Standard: Standard Depth of Investigation from the inversion, [m].
   
• TauRho/TauPhi DOI Conservative as Elev.: Conservative Depth of Investigation from the inversion. Transformed to elevation values, [m].
   
• TauRho/TauPhi DOI Standard as Elev.: Standard Depth of Investigation from the inversion. Transformed to elevation values, [m].
   
• TauRho/TauPhi at DOI Conservative: The Tau of the model at the DOI Conservative cutoff, [sec].
   
• TauRho/TauPhi at DOI Standard:The Tau of the model at the DOI Standard cutoff, [sec].
  
   
• C DOI Conservative: Conservative Depth of Investigation from the inversion, [m].
   
• C DOI Standard: Standard Depth of Investigation from the inversion, [m].
   
• C DOI Conservative as Elev.: Conservative Depth of Investigation from the inversion. Transformed to elevation values, [m].
   
• C DOI Standard as Elev.: Standard Depth of Investigation from the inversion. Transformed to elevation values, [m].
   
• C at DOI Conservative: The Tau of the model at the DOI Conservative cutoff.
   
• C at DOI Standard:The Tau of the model at the DOI Standard cutoff.

 

System

The System tab include all the system related visualization options:

• Pitch: Input receiver pitch, [degrees].
   
• Pitch Inverted: Receiver pitch from inversion, [degrees].
   
• Pitch Difference: Pitch Inverted minus Pitch, [degrees].
   
• Pitch STD: The standard deviation on the pitch, [factor].
  
   
• Roll: Input receiver roll, [degrees].
   
• Roll Inverted: Receiver roll from inversion, [degrees].
   
• Roll Difference: Roll Inverted minus Roll, [degrees].
   
• Roll STD: Standard deviation on the inverted roll, [factor].
   

The visualizations behave similar to other point themes, one can always edit the point size or the color scale later. They can also be gridded and used to make images. It can for instance be quite useful to make grids of the data residual and plot those as grids on line on sections along with the models.

One final composite Model Quality theme

There is one commonly used composite model quality theme that is not made with a model quality node. Add a data node like like an AEM data node to the GIS. This shows GPS positions of all the data. Then add a model selection node on top of that with all the models. The places where one can still see the data node, is the places where data has been discarded either as coupled data or as non-production data. Combining this map with GIS infrastructure maps or even just background images can be quite useful.