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Advanced Estimation - Fit Models
To access this dialog:
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Using the Advanced Estimation dialog, select the Fit Models menu item.
This panel is used to load and view the experimental variograms created on the Create Variograms panel and then apply the automatic fitting option to fit a model variogram set. The model variograms can then be edited manually if required.
This panel is only visible if Supervisor data is not being imported. You decide this using the Scenario Setup screen.
A model variogram set may include more than one model. If the multivariate model option is selected then the set will include a model variogram for each variable and a model cross-variogram for each pair of variables. The variograms and cross-variograms will have the same rotations, number of structures, structure type and ranges. If the model set is univariate then it will include just a model for each variable. Although it is possible to have univariate models for more than one variable in a model set the estimation process is more flexible if you keep to a single univariate model for one variable in each model set.
Using this panel you can:
- select the grades and experimental variograms to be displayed and analyzed
- Choose the model fitting variogram you wish to use (Variogram, Log Variogram, Madogram etc.)
- automatically fit 3D variogram models, both univariate and multivariate
- adjust model parameters through the graphical interface
- load external variogram models for comparison and modification
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Note: Advanced Estimation is part of the Studio RM toolset. Additional licensing modules aren't required.
Field Details:
Experimental Variogram
File: if variograms have been created using the Create Variograms
panel, the name specified there will be shown in this field. You can
also access any previously-generated file using the browse button.
The main differences between the variogram
models for COKRIG and ESTIMA
are:
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A variogram model set number (VSETNUM) is used instead of a variogram reference number (VREFNUM)
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The variogram model requires two additional fields GRADE and GRADE2 to identify the grade or grades in the case of cross-variograms, to which the model applies.
The experimental variogram file will use the following fields, if present:
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GRADE: primary grade, or if absent the grade being estimated is used instead
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GRADE2: secondary grade, or if absent, GRADE will be used (if available) or the grade being estimated if neither GRADE nor GRADE2 are available.
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VSETNUM: the variogram set number, if available, otherwise VREFNUM is used instead
As such, input variogram files from either COKRIG or ESTIMA / ESTIMATE processes can be used in advanced estimation.
Variogram Type: choose the variogram to which the model will be fitted. By default, a normal variogram will be used, but you can also choose the following:
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Variogram (default)
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Covariance
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Pairwise Relative
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Log Variogram
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Madogram
If a model has already been fitted, adjusting the Variogram Type will automatically update the display and candidate model set.
Zone selection: if you specified a ZONE field on the Select Samples panel, you will be able to switch between zonal variograms using the buttons in this section. If you did not select any zones an "All zones" button will be displayed.
Display downhole: if this box is ticked the table below will show only downhole variograms for selection. This check box is only available if variograms were calculated as downhole items using the Create Variograms panel. If it is not ticked (default) the table will show all variograms except downhole.
These variograms will not influence model fitting.
Select perpendicular variograms: if this option is selected then when you select a variogram other variograms that are perpendicular to the selected variogram will be selected automatically.
Display Grid: this table includes all possible variogram options for the currently selected options above. You can display results for downhole (if available) and/or directional items (if available). In all cases, you will be able to select a non-downhole, directionless option, assuming variograms have been created using the Create Variograms panel.
Each item in the grid is supported by the following information:
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Display: show or hide the variogram for the selected variable, type and direction.
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Dh: if the item is a downhole variogram this will state 'Yes', otherwise 'No'
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Major: if selected, this determines the major direction of the variogram model. Only one item in the table can be selected.
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Semi-Major: if selected, this determines the semi-major direction of the variogram model. Only one item in the table can be selected.
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Azimuth and Dip: the direction that applies to the current item. If Major is selected, this will be used to define the azimuth and dip of the major direction used for fitting. If Semi-Major is selected for the item, these values will determine the azimuth and dip of the semi major fitting direction.
Variogram / Cross-Variogram grid: you can view variograms and cross-variograms for any combination of variables (as defined on the Select Samples panel). Using this grid, you can select or deselect variables for variogram model fitting. Select each required variable by clicking in the boxes of the first column. Each pair of selected variables is then shown by the green grid squares. Click a green grid square to display a set of variograms or cross-variograms :
If normal score variograms have been generated,
you can swap between Transformed
grades and Untransformed
grades output using the respective radio button, e.g.:
The Variogram View: the central area of this panel is reserved for the display of variogram charts and thumbnails. There are three distinct areas:
Area (1) is a simple toolbar that allows you to (from left to right): save, copy (to clipboard), print, print preview, toggle 3D mode and show/hide the chart legend.
Area (2) is the display area for the main chart - using this view you can adjust the lag distance in real-time using the slider bar provided, and if a model has been fitted, you can manually edit the model anchor points (optionally restricting the editing based on settings found in the Model Parameters tab.
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When adjusting the Minimum lag distance, you need to ensure that the distance set is supported by the selected experimental variogram, i.e. the variogram must have sufficient resolution. You can adjust the lag distance for all directional variograms (All directions) or you can select one or more of the thumbnail views (using <SHIFT> or <CTRL>) and only apply the lag distance changes to those items (Highlighted directions). |
Area (3) shows a thumbnail view of the other variograms that were generated using the previous panel. Both this area and the main chart area are updated automatically as a result of changes made in other parts of the panel, for example, the Variogram Grid selection settings.
Click on the thumbnail view to load the variogram into the display area. Use the <CTRL>key to select multiple variograms for display.
Auto. Fit tab: this tab is used to control the actual model fitting process. It is here that you define variogram model structures, types and extents. When a model has been fitted its parameters are displayed in the Model Parameters tab. More...
Manual Fit tab: this tab contains options to allow you to manually fit a model to the variogram(s) using the specified number of structures. Click Manual Fit to generate a model line. When a model has been fitted its parameters are displayed in the Model Parameters tab. More...
Model Parameters tab: the variogram model parameter values can be restricted using the options found on this panel. This area also gives you access to summary information and review rotation, nugget and structural parameters. More...
Save Models tab: this tab displays a list of all candidate models. Fitted variogram models will be automatically saved to the list shown in this tab. This area is also used to define estimation runs for grade interpolation. More...
Format tab: this tab provides access to general visual formatting options for the Fit Models panel. More...
