This is a deprecated module that has been supplanted by Krig_2D
General Module Function
The Krig Z module models two-dimensional parameter distributions within domains defined by the convex hull of a data set, within a rectilinear domain with equally spaced nodes, or a technique called Convex Adaptive Grid (This feature available only in EVS PRO and MVS) which uses the convex hull option, and then subdivides individual elements to place a "kriged" node at the location of each input data sample. This guarantees that the output will accurately reflect the input at all measured locations (i.e. the maximum in the output will be the maximum of the input). This option is now the default gridding option. Krig Z creates a layer of quadrilateral (4 node) elements in which each node is assigned the kriged parameter value, and its associated kriging confidence level and uncertainty. Upon execution of the module, Krig Z produces a new input data file with a synthetic boring at the location of maximum uncertainty calculated from the previous kriging estimates, which can then be rerun to find the next area of highest uncertainty. The naming of the "DrillGuide©" file which is created when Krig_Z is run with all types of chem files ends in csv1, csv2, csv3, etc. the output file name will be .apdv2, csv3, csv4.... There are no limits to the number of cycles that may be run.
The use of Krig_Z to perform analytically guided site assessment is covered in detail in Workbook 2: DrillGuide© Analytically Guided Site Assessment.
This process can be continued as many times as desired to define the number and placement of additional borings that are needed to reduce the maximum uncertainty in the modeled domain to a user specified level. The features of Krig Z make it particularly useful for optimizing the benefits obtained from environmental sampling or ore drilling programs. Krig Z also provides some special data processing options that are unique to it, which allow it to extract 2-dimensional data sets from input data files that contain three-dimensional data. This functionality allows it to use the same .apdv files as all of the other EVS input and kriging modules, and allows detailed analyses of property characteristics along 2-dimensional planes through the data set. Krig Z also provides the user with options to magnify or distort the resulting grid by the kriged value of the property at each grid node. Krig_Z also allows the user to automatically clamp the data distribution to a specified level along a boundary that can be offset from the convex hull of the data domain by a user defined amount.
Module Input Ports
Krig_Z's only (Yellow-Blue-Yellow) input port is to allow the sharing of file names between similar modules. This should simplify the task of specifying data file names ESPECIALLY when using the ODBC modules such as DB_to_CSV_GEO. The output ports come in 3 color varieties:
Yellow-Blue-Yellow: YBY analyte (e.g. chemistry) or PGF files only
Yellow-Blue-Orange: YBO analyte (e.g. chemistry) or Geology Files
Orange-Blue-Orange: OBO Geology Files only
This coloring scheme is our best attempt to help you remember which modules you may want to share filenames. For example, DB_to_CSV_GEO can create analyte (e.g. chemistry) and geology files. Its colors are common to both file types and it could connect to all three types of modules. Map_Sheres and file_statistics are similar. The other modules read only one type.
Warning, there are no connection restrictions. You can (potentially incorrectly) connect analyte (e.g. chemistry) filenames to geology modules. However, this should not cause crashes and should issue a warning to the console when you try to run the module.
Module Output Ports
Krig_Z has three output ports (except when the Plot Semivariogram option is selected). The first of which (furthest to left) is to allow the sharing of file names between similar modules. The second outputs a 2D data field that can be input to any of the Subsetting and Processing modules that have the same color input port. The third port outputs a geometry of the component surface which can be input directly to the viewer. Connecting the geometry port directly to the viewer allows use of the clamping functions in Krig Z postprocessing to quickly investigate the distributions of components within specified ranges.
When the Plot Semivariogram option is selected three additional output ports will appear as in the above figure. The first new one is a red/white port that outputs a geometry of the calculated semivariogram. The next (blue/black) port outputs a 3D data field representing the lines (semivariogram cloud pairs) and is provided primarily for connection to the axes module. The last port is the Z_Scale of the semivariogram plot and is also provided primarily for connection to the axes module.
Module Control Panel
The control panel of Krig Z is shown in the figure above. The Read Chem File button opens a File Browser which lists the *.apdv;*.shp; or *.dbf files that are present in the current directory shown in the directory window. The format of .apdv files is described in the 3D analyte (e.g. chemistry) (.apdv) Format help topic.
This module will not begin running until a valid chem file is chosen and the Accept All Current Values button is pushed. The New check box is used to reset all of the parameters for a new run of Krig_Z with a different data set (without having to re-instance the module or manually reset all of the expert system calculated variables to zero). The Data Component Slider allows the user to select which of the property values in the .apdv file will be kriged by execution of the module. The default value is -1, which results in kriging of all of the data components in the file during a single execution of the module. A value of 0 corresponds to the first property of 15 that can be included in the .apdv file.
The "Run" toggle controls whether the module will run when applications are loaded or data changes. When this is on, the module runs when applications are loaded or the "Accept" button is pushed. When it is off, the module will not run.
Note: The "new" toggle on the main panel (on by default) resets all expert system calculated variables to zero before each run. This allows multiple calculations to be performed without tedious manual resetting of these variables. To change an expert system calculated variable, the toggle must be off.
The "Max. Uncertainty Location" toggle is used to control the visibility of the gray sphere that marks the location of maximum uncertainty. This toggle is made invisible if the Min/Max Plume option under Kriging Parameters is selected. For more information on Max. Uncertainty Location, see Workbook 2 DrillGuide©.
When the module has been executed once, and the user wishes to run it again with different parameter settings for the processing or kriging, the individual subpanel can be accessed to change the desired input, and then the module can be run by pressing the Accept All Current Parameters button.
Module Parameter Subpanels
Krig Z has four subpanels, which allow the user to set the parameters used for preprocessing the input data, producing the semivariogram, executing kriging, and post processing kriged output. Clicking on either of the check boxes next to the subpanel names, or on the names themselves will bring up the subpanel parameter screens. Note that the subpanels can only be closed by clicking on the box in the Module Control Panel, and not by double clicking on the subpanel's window control icon (the small horizontal bar in the upper left corner of the window).
The Preprocessing Parameters subpanel is shown in the figure above. It is important to note that all preprocessing actions are applied directly to the data in memory, and that the original data file is not altered. However, all of the functions within Krig Z and the modules downstream of Krig Z will be using the preprocessed (and kriged) parameter distribution. The user should refer back to the preprocessing subpanel when setting values for the filtering and display of the kriged data (i.e., to correctly specify whether the data has been log transformed, scaled, and/or clipped). The Data Processing radio buttons allow the user to specify whether the data will be used as is, or will be processed to compute the log base 10 of the parameter value before kriging. Note that if the log10 of the data is taken, the Clip Min value will be used to replace any zero values in the data with the specified value, which eliminates possible errors associated with attempting to take the log of 0. The Data Scaling input field is used to specify a value by which all nodal property values will be multiplied before kriging. The default value is 1, but the user can specify any negative or positive value, excluding 0. The number entered into the Clip Min input field will be used during preprocessing to replace any nodal property value that is less than the specified number. The default value for Clip Min is 0.0001, but the user can enter any reasonable number. Generally, Clip Min should be set to a value that is one-half to one-tenth of the lowest detection limit in the data set, unless the user wishes to make the influence of non-detected values stronger. As an example, if the lowest detection limit is 0.1 (which is present in the data set as a 0), and the user sets Clip Min to 0.0001, the clipped non-detected values force three orders of magnitude to be present between any detected values and non-detected values. The number entered into the Clip Max input field will be used during preprocessing to replace any nodal property value that is greater than the specified number. The default value for Clip Max is 1E08, but the user can enter any reasonable number. The clipping values can also be used to lessen the importance placed on extremes of the data, or outlier data values, before kriging. The preprocessing functions can be used in various ways to investigate the kriging confidence levels within specified ranges or limits of the data sets. An example of this type of analysis is provided in the Geostatistics in EVS manual.
The Semivariogram Parameters subpanel is shown in the figure above. The pair search range specifies the radial distance from any input data point that will be searched to assemble the data pairs that are used in the variance analysis. The values in the data windows are changed by clicking in the window and using standard windows style editing procedures. The default value for the pair search range is set to 0, which if left unchanged, results in the value being set to approximately 2/3 of the largest distance between data points in the data set. The user must consider the spatial characteristics of the data set when setting or revising the default calculated Pair Search Range. If large areas exist in the data domain that do not have data points within them, the user must set the Pair Search Range to a value that will allow a pair of data points to be identified, if these outlying data are going to affect the characteristics of the semivariogram. Data sets with large variations over short distances can be modeled most accurately using smaller pair search ranges, as this effectively limits the distance over which the semivariogram will search for and include data points.
If a large number of data points exist in the data set which are in close proximity to each other, the user should set the pair search range to the shortest distance that will allow trends in the data to be included in the semivariogram production. This is an important factor in the execution time required for calculating the semivariogram, as the number of data pairs to be considered is on the order of n squared, for n data samples. If a large data set is being kriged using a large Pair Search Range, the number of pairs the best-fit variogramming procedure must consider also gets very large. However, including a greater number of data pairs in the semivariogram analysis will generally produce kriged distributions that more accurately represent trends and other larger scale characteristics of the data set. EVS implements a deterministic random pair selection algorithm to limit the total number of pairs that are considered in the semivariogram production when the number of potential pairs exceeds 50,000. This algorithm speeds execution and allows the user to krige very large data sets. The flexibility of EVS's modular interface allows the user to experiment with different search ranges (preferably starting small and getting larger), with the same display and other downstream module parameters to obtain the desired results with reasonable execution times.
The Semivariogram Symmetry parameter describes the degree to which EVS's expert system is allowed to distort the geometry of the semivariogram in calculating the best fit to the data. The valid range for this parameter is from 0 to 1. The default value is 1, which forces the semivariogram to be symmetrical in all axes of the data set. Symmetrical variograms run the fastest in EVS, and give reasonable results for many data sets. Unless the data being kriged shows a very high degree of asymmetry, good results are generally obtained by setting this parameter to a value between 0.5 and 1. When utilizing symmetry values less than 0.5, the user should post the original data set and examine areas of the resulting model in which only sparse data are available to fully understand the effects of the asymmetric model semivariogram.
The Minimum Range parameter defines the smallest distance in the XY plane at which the semivariogram procedure can set the sill of the semivariogram. In essence, this parameter constrains the minimum distance between data points beyond which EVS's best fit algorithms will consider all points to have an equal and minimum influence on the kriged model node value. The default value for the Minimum Range is 0, which allows the best fit procedure to calculate the range that produces the best fit to the data. The valid range for this parameter can be any number up to the largest distance between points in the data set. However it is generally not meaningful to set the minimum range to values less than approximately five times the shortest distance between data points. When this value is changed from 0, the user should check the calculated range to see if the specified value constrained the semivariogram production, which is indicated when the calculated range is set to the specified value (the output of the semivariogram and kriging procedures is displayed in the console window). If so, the user may want to experiment with different range values, or allow the default value to be used, and compare the kriged results.
The Plot Semivariogram toggle causes a plot to be generated showing the semivariogram that has been selected and how the semivariogram surface fits to the data pair's semivariance cloud. What is plotted is one-half of the square of the differences vs. the vector distance between the pairs. This is referred to as the semi-variance cloud. The total length of lines above the surface and below should be equal. However in general, the population of points below the surface will be greater (since there will be some large, squared differences balancing). This behavior was different prior to Version 4.5. The "Z_Scale" parameter has a default value of NULL, but a reasonable default value will be automatically computed based on the maximum semivariance and the variogram Pair Search Range.
When the "Square Plot (vs. round)" toggle is OFF, the semivariogram surface will be round. Additional information on this subject is in the Semivariograms chapter of the Geostatistics Workbook.
The user can now set the semivariogram by checking the Set Semivariogram toggle This feature is useful for incorporating a semivariogram that was not calculated with the expert system. Type in boxes are supplied for Major Axis Rotation, Major Range, Sill, and Minor Range. Rotation angle requires an angle measured in degrees from East (equals 0) in a counterclockwise direction. The Major Range refers to the long axis of anisotropy (if any) and the Minor Range refers to the perpendicular of that axis. Note that both ranges refer strictly to the horizontal direction.
Note: The "new" toggle on the main panel (on by default) resets all expert system calculated variables to zero before each run. This allows multiple calculations to be performed without tedious manual resetting of these variables. To change an expert system calculated kriging variable, the toggle must be off.
The Kriging Parameters subpanel of Krig Z is shown in the figure above. The Min X, Max X, Min Y, and Max Y, inputs allow the user to define the horizontal domain within the data set in which kriging of the parameter distribution will be completed. Krig Z can utilize a model domain that is bounded by the convex hull of the data set, by a rectilinear domain, or by a convex adaptive grid.
The Bounds radio buttons (located below the Clamp Bnd. Off / Spacing input fields) allows the user to select the type of domain in which the kriging will be completed. A convex hull boundary should be utilized when the user wishes to produce a model that can have irregular boundaries that are defined by the extent of the measured data points. The convex hull of a data set can be thought of as the domain that would be outlined by stretching a rubber band around the external data points in the data set. The convex adaptive grid (This feature available only in EVS PRO and MVS) is the same as the convex hull grid, except that the grid is automatically adapted to place grid nodes at all of the measured data points. The adaptive grid will result in a kriged parameter distribution that honors all of the measured data points exactly. This is the default domain used by Krig_Z. Utilizing a convex hull boundary effectively minimizes the extrapolation of parameters within the model to that area which is enclosed by the measured data points, or by some specified offset (see discussion below). A value of 0 for the Min and Max X and Y parameters is the default, which results in a model domain that is defined by the limits of the data set within a horizontal plane. If the user is uncertain of the X, Y and Z limits of the data domain, the module should be run with the default 0 values, and upon completion of execution, the values in the X, Y, and Z input fields will be the min and max values of these parameters in the data set.
The Min and Max Z values define the vertical domain from which Krig Z will select the data to be kriged, based on the Extract Method chosen.
The Extract Method radio buttons (located below the Xres/YRes input fields) allow the user to extract data from within the interval specified in Min Z and Max Z using three different methods. It should be noted that if multiple samples occur at the exact same x, y, and z coordinates (duplicate samples), the average of these samples will be calculated first to provide a single data point for that coordinate, and then the extract method will be applied to other samples in the specified depth interval. If the Average radio button is selected, then Krig Z will search the vertical interval in each boring and calculate the average of all the values found for input to the kriging analysis. If the Maximum radio button is selected, then Krig Z will extract the maximum property value that exists within the specified Z interval. When the Slice radio button is chosen, Krig Z will look for the closest data point above the specified Min Z value, and the closest data point below the specified Min Z value, and calculate the average of these two points for input to the kriging analysis. The Slice Extract Method is provided as a convenient method for the user to assemble a 2-D data set that will contain at least one data point from each sampling location. If only one data point exists for a sampling location, then that value will be extracted for that location whether it is actually located above or below the specified Min Z value. Note that the Max Z value is not used when the Slice Extract Method is chosen.
The Statistics Option radio buttons determine the type of statistical information which will be included in the nodal data components output from Krig_Z.
If Statistics is chosen, Each Concentration (for every chemical in the .apdv file) will have a corresponding Confidence (based on the Confidence Bound parameter) and Uncertainty. The title for Confidence Bound changes depending on whether you have selected Log pre-processing. The window above shows the title when Log is NOT selected. In this case the Confidence Bound is a plus-or-minus tolerance versus a multiplicative factor (when Log processed).
If Min-Max Plume is chosen (This feature available only in EVS PRO and MVS), three different Concentration components will be calculated. The nominal Concentration, Minimum & Maximum. These different distributions are determined based on the standard deviation and nominal concentration at each node based on the "Confidence for Min/Max Plume" parameter (nominally 60%) as shown above.
The Drill Guide Cycles field allows Krig_Z to run in an automated loop to run any number of cycles to define optimal new locations for sampling in a fully automated fashion. This allows automatic cycling (reading the new data file and running) until the synthetic file name's suffix matches the number specified (e.g. if set to 30 for the file css_0.apdv it will run until the filename is css_0.apdv30).
The Reach input field defines the radial distance (in user units) from any given model node that the kriging module will look for data points to be included in the estimation of the model parameter at that node. The default value of reach is 0, which results in the module calculating a reach value which is approximately two-thirds of the largest distance between any two data points in the data set.
The Points parameter defines the maximum number of data points (within the specified reach) that will be considered for the parameter estimation at a model node. The default value for points is 20, which generally provides reasonably smooth modeled parameter distributions. The effects of decreasing and increasing the values for reach and points on the model output can be somewhat similar, but for different reasons. If the data have a fairly even spatial distribution throughout the domain, then increasing these values will generally include more of the input data points that will be used to krige the value for a given model node, and thus will result in smoother modeled data distributions.
Decreasing the values of reach and points (in an evenly distributed data set) results in fewer input data points being used to calculate the parameter estimates at a given model node, and result in modeled distributions with greater variations across smaller areas. The user should consider both the spatial distribution and the range of values in the input data set when deciding upon values for the reach and points parameters. If the specified reach is too small to allow the kriging module to locate at least one point within the search area, then no kriging will be completed at that model node, the nodal value will be set to 0, and the confidence level will be set to <0.1%. Note that this nodal value is generally inappropriate, and the regions of the model receiving the 0 values should be subsetted out of the domain by using an plume_volume module with a confidence isocomponent of 1%. If the user specifies a large number of points (that are within the specified reach), then the output will be smoother, but the execution time for the kriging can increase significantly. By posting the input data using the post_samples module, and looking at the characteristics of the resulting kriged data using the Statistics module, the user can quickly analyze the characteristics and distribution of the kriging output for a given set of parameters, and test the effects of changing the kriging parameter values.
The "Quadrant Search" toggle changes the method by which data sample points are selected for inclusion in the kriging matrix. If this is on, the "Points" parameter switches to "Max Points in Quadrant". Searching is performed for each of the four quadrants surrounding the point to be kriged. Within each quadrant a maximum number of points (up to one-half of the total points) are selected. Then, points are taken sequentially from each quadrant up to the maximum number of total points or until all quadrant's points have been used. The panel display changes when this option is selected as shown above. Quadrant Search is applicable for all kriging modes and options.
The X Res and Y Res parameters specify the number of grid nodes that will be included within the X and Y axes of the model domain. The number of grid elements along any axis of the model is simply the axis Res value minus one, as every element has two bounding nodes along an axis. The default value for the X and Y Res parameters in Krig Z is 51. However, the user can specify any number desired, up to the limit of available memory resources in the computer. The robust kriging algorithms in EVS generally produce reasonable modeled distributions with a fewer number of grid nodes than the user may be used to, so the recommended procedure for setting the axis Res parameters is to start with less, and then increase the value until an acceptable model is obtained.
The Clamp Bnd. Off. parameter specifies the distance outside of the Convex Hull of the data set that a boundary (or ring) of synthetic data points, which have property values that are equivalent to the specified Clip Min, will be automatically generated for kriging. The synthetic data points are not used in the production of the semivariogram, but are used only during the kriging to control how extrapolation is done outside of the data set. The Spacing parameter sets the linear distance along this clamp boundary at which the synthetic data points will be placed. The default value for Clamp Bnd. Off. is -1, which specifies that no clamping boundary should be used. The user can set this value to any distance in user units that is within the kriging Reach distance specified, to modify how sharply the kriged data distribution will transition to the clamped value. The default Spacing parameter value is 0, which specifies that no points will be placed along the clamp boundary. Again, the user can input any value in user units that will provide the desired modeled data distribution. Note that the Clamp boundary is only used with modeled domains that are defined by the Convex Hull. It is not used for rectilinear model domains.
The user should be aware that the synthetic data points do not affect the kriging semivariogram production, but they do affect the kriging confidence and uncertainty values that are output by Krig Z, as they are considered by the kriging algorithms to be real data points. Therefore, a clamping boundary should not be used when confidence or uncertainty values are of importance to the analysis. The clamping boundary is provided primarily as a display control tool, and will produce a very even and regular synthetic boundary along the outside of the data domain.
The Convex Hull Boundary Offset parameter sets the distance in user units that the convex hull for the kriging domain will be set outside of the actual convex hull of the data. This parameter allows the user to specify the distance outside of the actual data in which the parameter values will be extrapolated. The default value for Convex Hull Boundary Offset is 0 units, which specifies that the true (not offset) convex hull of the data set will be used when the "New" toggle is OFF. The user can specify any distance desired, as long as it is within the kriging reach specified. When the New toggle is ON and Convex Hull OR Convex Adaptive Gridding is used, the offset will be set to a minimum of 5% of the x-y spatial extent. Any positive value may be specified when New is OFF.
The Confidence Bound parameter is used to specify what interval around the kriged model estimates the kriging confidence or uncertainty will apply to. The default value is 10, which essentially produces the confidence and uncertainty that the kriged data are within one order of magnitude of the "true" value. As an example, if the Confidence Bound is 10, the kriged property value at a node is 5, and the resulting kriged confidence level at the node is 0.9, then 90% of the time, the "true" value of the kriged property at that node will be in the range of from 0.5 to 50 units. Additional discussions of the applications of the kriging confidence and uncertainty are provided in the Geostatistics in EVS manual.
The Confidence parameter is used to specify the confidence level to be used in determining the Min - Nominal - and Maximum Concentration predictions. This parameter is used only if Min-Max Plume is chosen.
Target Concentration for Drill Guide Cycles is a parameter that focuses the optimization of sample location selection towards the goal of refining the extent of a user defined plume level. The value is input in normal units even if you have the Log Processing option selected.
The Postprocessing subpanel for Krig Z is shown in the figure above. Postprocessing of the data from Krig Z affects the calculation of the kriging uncertainty estimates that are produced by the model, and allows the user to apply a filter for the data passed to all modules downstream of Krig Z. Note that the postprocessing does not affect any of the other semivariogram or kriging algorithms that execute in Krig Z, so the user can experiment with different values of postprocessing parameters to obtain the type of display desired, without changing the internal kriging process.
The Data Scaling Factor allows the user to magnify the surface coordinates in the Z direction by a specified factor, which produces a surface that is distorted according to the kriged value at the nodes. Essentially, the data scaling algorithm produces a Z coordinate for each node that is equivalent to the nodal data value multiplied by the specified scaling value, and then displays the resulting surface using a Z axis range that spans the scaled values. In contrast to the Data Scaling factor specified in the preprocessing parameters, the postprocessing scaling does not affect the kriged data value at the node, only the Z coordinate used for display of the surface. The default value for the Data Scaling Factor is 10, but this number is arbitrary and the user should select a value that is appropriate for the range of input data values used. For log processed data, a value of 10 produces 10 Z units per decade of the nodal data value. The user must keep in mind that it will be the scaled Z coordinates that are passed from Krig Z to all modules downstream, and thus the values of parameters in any downstream modules must be set accordingly. This value can be changed interactively without re-running the module.
The Clip Min parameter specifies the smallest nodal value that will be present in the data field output by Krig Z. This parameter is useful for limiting or enhancing the effects of non-detected values or outliers in a data set, and for optimizing the use of the dynamic color range used to represent the property distribution. Clip Min has a default value of 0.001, but can be set to any negative or positive value with magnitude form 1.0 E-09 to 1.0 E09. In general, maximum use of the dynamic color range can be obtained by setting this value to the lowest property value or detection limit in the input data set. It should be greater than the preprocessing Clip Min.
The Clip at Max parameter specifies the largest nodal value that will be present in the data field output by Krig Z. Checking this box will clip the parameter distribution output by Krig Z to the value specified in the input field. Clipping of the data only occurs when Krig Z is executed, so the user must rerun the module if they want to change this value and have the output data clipped. If the user wishes to view different ranges of the data in the output of Krig Z without rerunning the module and clipping the actual data range, the Clamp at Min/Max parameters can be used (see discussion below). If the Clip at Max box is not checked, then max clipping will not occur. Again this parameter can be used to optimize the use of the dynamic color range when a data set has a few extremely high values, but the user is most interested in seeing the detailed changes in the distribution in some lower range of the data. It can also be used to investigate the kriging confidence or uncertainty levels near certain threshold values of a property. As an example, if the regulatory threshold for a parameter is 10 units, then the Clip Max parameter can be set to 10, and all kriged values greater than 10 will have the same strength in the calculation of the uncertainty levels in the kriged distribution. Clip Max has a default value of 100, but can be set to any negative or positive value with magnitude from -1.0E25 to 1.0E25.
The Data Component radio buttons allow the user to view the concentration, confidence and uncertainty distributions that are calculated for each data component in the input file. Remember that the components are numbered from 0 to 15 in the input file, and this number appears at the end of each of the component properties listed above the Data Component label. When viewing the component properties for multiple components, the associated concentration surface is automatically used for the display. As an example, the Uncertainty calculated for component 1 in the data file will be listed as "Uncertainty1", and selecting this radio button will display the uncertainty distribution on the concentration surface for "Concentration1".
The Clamp at Min/Max check box is used to limit the range of the values that are displayed when the Krig Z module geometry port (rightmost port) is connected directly to the viewer. Selecting this check box and entering values in the input fields affects only the display of the data in the viewer, and does not affect the actual range of data that is output through the (blue-black) data field port of Krig Z (leftmost port) to other modules. Clamping is useful for maximizing the use of the dynamic color range within user specified bounds.
Krig_Z Module Hints
Manually adjusting kriging and semivariogram parameters
The user must uncheck the new toggle in the main window in order to make manual adjustments to most parameters in this module. Otherwise the values will be calculated by EVS according to the spatial extents or distribution of the data.
When using the set semivariogram option, all other semivariogram parameters are ignored. But to go back to the expert system parameters the user must make all type-ins 0,00 (in set semivariogram), then check the new toggle on the main Krig_3D panel.
Why does EVS crash every time I try to run Krig_Z with my dataset?
If EVS is crashing during kriging runs, then there is probably an instability with the current data set and the adaptively gridded mesh created. A common scenario is with adaptive gridding around a sample located very close to an existing grid node. Try increasing your resolution to avoid the instability or turning adaptive gridding off. Usually, a change of one grid size division in the X or Y direction will fix the problem.