ESTIMA Process

To access this process:

See this process in the Command Table.

Process Overview

The ESTIMA process provides a choice of methods for grade estimation of a block model.

For in-depth conceptual information on the ESTIMA process, and grade estimation in general, see Grade Estimation Introduction.

ESTIMA provides the following grade estimation methods:

Nearest Neighbor (NN).
Inverse Power of Distance [IPD].
Ordinary Kriging (OK).
Simple Kriging.
Log Kriging.
Sichel's T Estimator.
Ordinary Macro Kriging
Simple Macro Kriging
F-value
Lagrange multiplier

Key ESTIMA features:

Multiple grades can be estimated in a single run.
The same grade can be estimated by different methods.
Different search volumes and estimation parameters can be used for the different grades.
Rectangular or ellipsoidal search volume with anisotropy.
Restriction of number of samples by octant.
Restriction of number of samples by key field.
Estimation by zone, with separate parameters for each zone.
Wide selection of variogram model types for both normal and lognormal kriging.
Automatic transformation of data if the &PROTO model is a rotated model.
Unfolding option available for all estimation types.
Optimization of sample searching to improve processing speed.
Parent cell estimation.
Selective update of a partial model.

If the input &PROTO model contains cells and sub-cells then values are interpolated into the existing cell structure. If &PROTO is empty then cells and sub-cells are created if there are sufficient samples within the search volume.

ESTIMA requires a search volume to be defined. This is the volume, centered on the cell being estimated, which contains the samples to be used for grade estimation. In fact more than one search volume may be defined, so that different grades can have different search volumes. The parameters describing the search volume(s) are supplied using the Search Volume Parameter file &SRCPARM.

Note: ESTIMA parameter files can be imported and transformed for use in COKRIG using the Advanced Estimation console's Parameters panel).

ESTIMA also requires a set of estimation parameters to be defined for each grade to be estimated. These parameters are also supplied to ESTIMA using a file - in this case the Estimation Parameter file. It will include items such as the estimation method, the search volume reference number and for example the power, if Inverse Power of Distance is selected.

Note: Search volume parameter files exported from the Advanced Estimation console cannot be used as an input to the ESTIMA process, or the ESTIMATE screen.

ESTIMA estimation methods include Nearest Neighbor, Inverse Power of Distance, and Sichel's t Estimator. MOD also includes Ordinary Kriging with a single structure spherical model variogram. The additional options in EGS are a choice of variogram models, lognormal kriging and Simple Kriging. Please consult your local Datamine office if you would like further information on these modules.

Note: When COKRIG or ESTIMA run Dynamic Anisotropy and less than 3 angles are used, the process replaces the missing angles with angles from the selected search or variogram.

ESTIMA and COKRIG

Key differences between ESTIMA and COKRIG:

In COKRIG, the octant method is not directly supported but can be approximated using the sector method with 4 sectors and a horizontal split.
Power and De Wijsian variogram models are not supported in COKRIG.
There is no option to reset negative kriging weights to zero in COKRIG.

Advantages of COKRIG over ESTIMA:

Multivariate geostatistics!
Optimized for parallel processing – speed increase approximately by a factor of the number of (virtual) cores on the computer.
Significant speed improvements when using large or multiple search volumes.
More flexible search volume parameters – segments/more than 2 additional search volumes.

The main differences between the variogram models for COKRIG and ESTIMA are:

A variogram model set number (VSETNUM) is used instead of a variogram reference number (VREFNUM)
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.

Variogram models from either COKRIG or ESTIMA can be specified when using COKRIG/Advanced Estimation.

Input Files

Name	I/O Status	Required	Type	Description
PROTO	Input	Yes	Block_Model_File	Input model prototype. This is a standard block model file containing the 13 compulsory fields. It may also contain the rotated model fields. If it includes cells then it must be sorted on IJK.
IN	Input	Yes	Table	Input sample data. This must contain X,Y and Z fields and at least one grade field.
SRCPARM	Input	Yes	Undefined	Search volume parameter file. This contains 24 compulsory fields defining the search volume and the number of samples needed for grade estimation. More than one search volume may be defined. All fields are numeric: SREFNUM Search volume reference number. SMETHOD Search volume shape. 1 = 3D rectangle 2 = ellipsoid. SDIST1 Max search distance in direction 1. SDIST2 Max search distance in direction 2. SDIST3 Max search distance in direction 3. SANGLE1 First rotation angle for search vol. SANGLE2 Second rotation angle. SANGLE3 Third rotation angle. SAXIS1 Axis for 1st rotation (1=X,2=Y,3=Z). SAXIS2 Axis for 2nd rotation (1=X,2=Y,3=Z). SAXIS3 Axis for 3rd rotation (1=X,2=Y,3=Z). MINNUM1 Min number of samples, 1st search vol. MAXNUM1 Max number of samples, 1st search vol. SVOLFAC2 Axis multiplying factor,2nd search vol. MINNUM2 Min number of samples, 2nd search vol. MAXNUM2 Max number of samples, 2nd search vol. SVOLFAC3 Axis multiplying factor,3rd search vol. MINNUM3 Min number of samples, 3rd search vol. MAXNUM3 Max number of samples, 3rd search vol. OCTMETH Octant method flag. 0 = no octant search, 1 = use octants. MINOCT Minimum number of octants to be filled. MINPEROC Minimum number of samples in an octant. MAXPEROC Maximum number of samples in an octant. MAXKEY Maximum number of samples with the same key value within an octant SANGL1_F Name of field in the input prototype model file that contains the first rotation angle for dynamic anisotropy. SANGL2_F Name of field in the input prototype model file that contains the second rotation angle for dynamic anisotropy. SANGL3_F Name of field in the input prototype model file that contains the third rotation angle for dynamic anisotropy.
ESTPARM	Input	Yes	Undefined	Estimation parameter file. Each record in the file describes an estimation method and its associated parameters. The fields are dependent on the estimation methods selected. All fields are optional except for VALUE_IN and SREFNUM. General fields: VALUE_IN 2A4 Field to be estimated. SREFNUM N Search volume reference number. VALUE_OU 2A4 Field to be created in MODEL (Default is VALUE_IN). {ZONE1_F} A/N 1st field for zonal estimation. The actual name of the field is given by ZONE1_F on command line eg ZONE1_F(ROCK). {ZONE2_F} A/N 2nd field for zonal estimation. NUMSAM_F 2A4 Field to be created in MODEL for the number of samples. SVOL_F 2A4 Field to be created in MODEL for dynamic search volume number. V VAR_F 2A4 Field to be created in MODEL for variance of estimate. MINDIS_F 2A4 Field to be created in MODEL for distance to nearest sample. IMETHOD N Estimation method. 1 = Nearest neighbour (NN). 2 = Inverse power of dist (IPD). 3 = Ordinary kriging (OK). 4 = Simple kriging (SK). 5 = Sichel's t estimator. 6 = Ordinary macro kriging. 7 = Simple macro kriging. 8 = Circular IPD, for estimating angles. 9 = Correlation factor method. 101 = F-value 102 = Lagrange Multiplier Fields for IPD and NN: ANISO N Anisotropy method: 0 = No anisotropy. 1 = Use search vol anisotropy. 2 = Use ANANGLEn. ANANGLE1 N Anisotropy angle 1. ANANGLE2 N Anisotropy angle 2. ANANGLE3 N Anisotropy angle 3. ANDIST1 N Anisotropy distance 1. ANDIST2 N Anisotropy distance 2. ANDIST3 N Anisotropy distance 3. POWER N Power of distance for weighting. ADDCON N Constant added to distance. Fields for kriging: VREFNUM N Variogram model reference number. VANGL1_FName of field in input prototype model MODEL used to define the first variogram rotation angle for dynamic anisotropy. VANGL2_F Name of field in input prototype model MODEL used to define the second variogram rotation angle for dynamic anisotropy. VANGL3_F Name of field in input prototype model MODEL used to define the third variogram rotation angle for dynamic anisotropy. LOG N Lognormal variogram flag. 0 = Normal kriging. 1 = Lognormal kriging. KRIGNEGW N Treatment of -ve weights: 0 = -ve weights kept and used. 1 = Ignore samples with -ve weights KRIGVARS N Treatment of variance > sill: 0 = Write variance to MODEL. 1 = Set variance to sill. Fields for lognormal kriging: GENCASE N Calculation method: 0 = Rendu's method. 1 = General case. DEPMEAN N Deposit mean [If 0 then use kriged estimate]. Fields for general case: TOL N Tolerance for convergence. MAXITER N Maximum number of iterations. Fields for simple kriging: LOCALMNP N Method for calculation of local mean: 1 = use field defined in PROTO 2 = use mean within search vol. LOCALM_F 2A4 Name of local mean field in PROTO; used if LOCALMNP=1
VMODPARM	Input	No	Variogram - Model	Variogram model parameter file. Each record in this file defines a variogram model type and its parameters. Only the VREFNUM field is compulsory. VREFNUM Model variogram reference number. VANGLE1 Variogram anisotropy angle 1. VANGLE2 Variogram anisotropy angle 2. VANGLE3 Variogram anisotropy angle 3. VAXIS1 Model variogram rotation axis 1. VAXIS2 Model variogram rotation axis 2. VAXIS3 Model variogram rotation axis 3. NUGGET Nugget variance. ST1 Variogram model type for structure 1. 1 = Spherical. 2 = Power [eg 1 - linear]. 3 = Exponential. 4 = Gaussian. 5 = De Wijsian. ST1PAR1 1st parameter of structure 1 [Range 1 for spherical model]. ST1PAR2 2nd parameter of structure 1 [Range 2 for spherical model]. ST1PAR3 3rd parameter of structure 1 [Range 3 for spherical model]. ST1PAR4 4th parameter of structure 1 [C variance for spherical model]. STn Variogram model type for structure n. STnPARp pth parameter for structure n, where n<=9.
STRING	Input	No	String	Input string file holding the boundary strings which define the stratified unit[s] for unfolding. 7 fields are compulsory: SECTION , BOUNDARY , PVALUE , XP , YP , ZP and PTN. 3 optional fields are WSTAG , BSTAG and TAG. The file must be sorted on SECTION , BOUNDARY PTN , with SECTION being the primary keyfield. It is assumed that the section numbering system is such that sorting on SECTION will ensure that physically adjacent sections are adjacent in the STRING file.

Output Files

Name	I/O Status	Required	Type	Description
MODEL	Output	Yes	Block Model File	Output model containing estimated grades, variance etc.
SAMPOUT	Output	No	Undefined	Output sample file containing details of weights for each sample for each cell estimated.

Fields

Name	Description	Source	Required	Type	Default
X	X coordinate of sample data in IN file. If not specified, then X is assumed. If the unfolding option is used, then the X coordinate must be set to the unfolded UCSA coordinate.	IN	No	Numeric	Undefined
Y	Y coordinate of sample data in IN file. If not specified, then Y is assumed. If the unfolding option is used, then the Y coordinate must be set to the unfolded UCSB coordinate.	IN	No	Numeric	Undefined
Z	Z coordinate of sample data in IN file. If not specified, then Z is assumed. If the unfolding option is used, then the Z coordinate must be set to the unfolded UCSC coordinate.	IN	No	Numeric	Undefined
ZONE1_F	First field for zonal control. A maximum of 202 zone combinations is permitted.	IN	No	Any	Undefined
ZONE2_F	Second field for zonal control. A maximum of 202 zone combinations is permitted.	IN	No	Any	Undefined
KEY	Key field used to specify the field limiting the number of samples for estimation. The field must exist in the IN file.	IN	No	Numeric	Undefined
LENGTH_F	Field used for length weighting in IPD. The field must exist in the IN file.	IN	No	Numeric	Undefined
DENS_F	Field used for density weighting in IPD. The field must exist in the IN file.	IN	No	Numeric	Undefined
SECTION	The name of the numeric field in the STRING file holding the section identifier; used if the unfolding option is required. The default field name is SECTION.	STRING	No	Numeric	SECTION
BOUNDARY	The name of the numeric field in the STRING file holding the boundary identifier; used if the unfolding option is required. The default field name is BOUNDARY.	STRING	No	Numeric	BOUNDARY
WSTAG	Within Section TAG; used if the unfolding option is required. This is a numeric field in the STRING file, defining the stratigraphical links between hangingwall and footwall points on strings within the same section. A value of 0 or - means that the point is not linked. The default field name is WSTAG.	STRING	No	Numeric	Undefined
BSTAG	Between Section TAG; used if the unfolding option is required. This is a numeric field in the STRING file, defining the stratigraphical links between 2 points on strings on adjacent sections with the same BOUNDARY. A value of 0 or - means that the point is not linked. The default field name is BSTAG.	STRING	No	Numeric	Undefined
TAG	A numeric tag field in the STRING file; used if the unfolding option is requires. It defines both the stratigraphical links between points on strings within the same section, and between points on adjacent sections with the same BOUNDARY. A value of 0 or - means that the point is not linked. The default field name is TAG.	STRING	No	Numeric	Undefined

Parameters

Name

Description

Required

Default

Range

Values

DISCMETH

Cell discretisation method:

Option	Description
1	- use XPOINTS , YPOINTS , ZPOINTS to define the number of points in the X,Y,Z directions
2	- use XDSPACE , YDSPACE , ZDSPACE to define the distance between points. The default is method (1).

1,2

XPOINTS

Number of discretisation points in X. (1)

Undefined

YPOINTS

Number of discretisation points in Y. (1)

Undefined

ZPOINTS

Number of discretisation points in Z. (1)

Undefined

XDSPACE

Distance between discretisation points in X if DISCMETH=2. The default gives just one point.

Undefined

YDSPACE

Distance between discretisation points in Y if DISCMETH=2. The default gives just one point.

Undefined

ZDSPACE

Distance between discretisation points in Z if DISCMETH=2. The default gives just one point.

Undefined

PARENT

Flag to control parent cell estimation:

Option	Description
0	- Estimate into individual subcells.
1	- Represent parent cell by a full 3D matrix of points.
2	- Represent parent cell by a 3D matrix of points, but select only points lying within subcells. The default is (0).

0,2

0,1,2

DYANKR

Flag to select whether the variogram model rotation angles should use the dynamic anisotropy option:

Option	Description
0	- Do not use dynamic anisotropy. Use angles VANGLEn as defined in the variogram model parameter file VMODPARM.
1	- If the search volume uses dynamic anisotropy, then the variogram model uses the same set of angles.
2	- Use dynamic anisotropy, but with a different set of angles from the search volume. The names of the corresponding fields are specified by fields VANGLn_F in the estimation parameter file ESTPARM.

0,2

MINDISC

Minimum number of discretisation points. Only used if PARENT=2. The default is (1).

Undefined

COPYVAL

Flag controlling copying of values from PROTO to MODEL if there is insufficient data to estimate them:

Option	Description
0	- Assign absent data value[s] in MODEL.
1	- Copy from PROTO to MODEL. The default is (0).

0,1

FVALTYPE

Flag for cell approximation for F values:

Option	Description
0	- The exact dimensions of the cell are used
1	- Each cell is approximated by one of a discrete number of cell sizes. The default is (1).

1,2

FSTEP

Step size for cell approximation. This is only used if FVALTYPE=2.

Undefined

XMIN

Minimum X value for model updating. The default is the X model origin.

Undefined

XMAX

Maximum X value for model updating. The default is the maximum X value for PROTO.

Undefined

YMIN

Minimum Y value for model updating. The default is the Y model origin.

Undefined

YMAX

Maximum Y value for model updating. The default is the maximum Y value for PROTO.

Undefined

ZMIN

Minimum Z value for model updating. The default is the Z model origin.

Undefined

ZMAX

Maximum Z value for model updating. The default is the maximum Z value for PROTO.

Undefined

XSUBCELL

Number of subcells per parent cell in X if PROTO is empty. The default is (1).

Undefined

YSUBCELL

Number of subcells per parent cell in Y if PROTO is empty. The default is (1).

Undefined

ZSUBCELL

Number of subcells per parent cell in Z if PROTO is empty. The default is (1).

Undefined

ALLWGTS

Flag controlling which samples are written to the sample output file if IMETHOD=9 [correlation factor method].

Option	Description
0	- Only samples with non-zero weights are written to the sample output file.
1	- All samples in the search volume including those with zero weights are written to the sample output file.

0,1

LINKMODE

The method by which links between strings are created; used if the unfolding option is required.

Option	Description
0	- Within section links are defined by the WSTAG field, or by the TAG field if WSTAG does not exist. Between section links are defined by the BSTAG field, or by the TAG field if BSTAG does not exist.
1	Within section links are defined automatically. Between section links are defined by the BSTAG field, or by the TAG field if BSTAG does not exist.
2	- Within section links are defined by the WSTAG field, or by the TAG field if WSTAG does not exist. Between section links are defined automatically.
3	- Within section links are defined automatically. Between section links are defined automatically. For simple structures it is not essential to define tag points on the strings; using the default value (3) ensures that automatic linking will be applied both within and between sections.

0,3

0,1,2,3

UCSAMODE

The type of UCSA coordinate; used if the unfolding option is required. Default (2).

Option	Description
1	- Coordinates are normalised.
2	- Coordinates are adjusted.
3	- Coordinates are true length.
4	- Coordinates are world X value.
5	- Coordinates are world Y value.
6	- Coordinates are world Z value.

1,6

1,2,3,4,5,6

UCSBMODE

The type of UCSB coordinate; used if the unfolding option is required. Default (3).

Option	Description
1	- Coordinates are normalised.
2	- Coordinates are adjusted.
3	- Coordinates are true length.
4	- Coordinates are world X value.
5	- coordinates are world Y value.
6	- coordinates are world Z value.

1,6

1,2,3,4,5,6

UCSCMODE

The type of UCSC coordinate; used if the unfolding option is required. Default (2).

Option	Description
1	- Coordinates are normalised.
2	- Coordinates are adjusted.
3	- Coordinates are true length.
4	- Coordinates are world X value.
5	- Coordinates are world Y value.
6	- Coordinates are world Z value.

1,6

1,2,3,4,5,6

PLANE

The plane of the structural interpretations defined in the STRING file; used if the unfolding option is required. Default (1).

Option	Description
1	- Vertical sectional interpretation.
2	- Interpretation in plan.

1,2

HANGID

The value of the field BOUNDARY in the STRING file that defines the hangingwall of the unit, used if the unfolding option is required. It will be used if the UNITDEF file is not defined.

Undefined

FOOTID

The value of the field BOUNDARY in the STRING file that defines the footwall of the unit, used if the unfolding option is required. It will be used if the UNITDEF file is not defined.

Undefined

TOLRNC

Tolerance in the calculation of the UCSA coordinate expressed as a proportion of the UCSA width; used if the unfolding option is required. The default is (0).

Undefined

UCSALIMT

Flag to define the limits of the UCSA coordinate if UCSAMODE=1 or 2 and TOLRNC>0. The options below are defined in terms of the Normalized mode [UCSAMODE=1]. Default (1)

Option	Description
1	- UCSA values can be less than 0 and greater than 1
2	- UCSA values can be less than 0. Values calculated as greater than 1 are reset to 1
3	- UCSA values calculated as less than 0 are reset to 0. Values can be greater than 1
4	- UCSA values calculated as less than 0 are reset to 0. Values calculated as greater than 1 are reset to 1

1,4

1,2,3,4

ORGTAG

Tag number of points which define the origin surface from which the UCSB coordinate is measured. The default surface if ORGTAG is undefined (-) is created from the first points on each of the hangingwall and footwall strings.

Undefined

Display control:

Option	Description
0	Minimum output including progress message.
1	As 0 plus details of input parameters.
2	as 1 plus display of each cell value. The default is (0).

0,2

0,12

Example

!ESTIMA &PROTO (PROTOMOD),&IN (SAMPLES),&MODEL (MODEL1),

&SRCPARM (SRCPARM1),&ESTPARM (ESTPARM2)

,&VMODPARM (VMODELS),

*ZONE1_F (ROCK),

@XPOINTS=3, @YPOINTS=3, @ZPOINTS= 3