ANISOANG Process

To access this process:

View the Find Command screen, select ANISOANG and click Run.

Enter "ANISOANG" into the Command Line and press <ENTER>.

See this process in the Command Table.

Process Overview

Note: This is a superprocess and running it may have an effect on other Datamine files in the project.

The processes ESTIMA and COKRIG include a dynamic anisotropy option that allows the rotation angles for the search ellipsoid to be defined individually for each cell in the model so that the search ellipsoid is aligned with the axes of mineralisation. This therefore requires the rotation angles to be interpolated into the model cells which in turn requires a set of angles as the input data file for interpolation.

Note: ANISOANG can work with both rotated and unrotated input data and can handle inputs of any rotation type.

See ANISOANG Workflow.

The ANISOANG process is designed to assist you to create a suitable input data file, and offers two methods for defining the dip and dip direction of the major axis of anisotropy:

Digitising strings in plan and section.
Calculating the angles from wireframe triangles.

If sections are used and are oriented in the dip direction then the output POINTS file will contain the true dip of the mineralisation. If sections are not oriented in the dip direction then the output POINTS file will include the apparent dip. The apparent dip should then be interpolated into the model and process APTOTRUE used to convert to the true dip.

Further information and examples are available in the Dynamic Anisotropy User Guide, and a worked example of ANISOANG.

Plan Strings

File PLANSTR contains strings digitised in a horizontal plan which can be used to define the strike, and the true dip direction is then calculated as 90o or 270o from strike. Alternatively the plan strings can represent the true dip direction, but this would not be the usual case. Parameter PLANMODE is used to define what the strings represent. The direction in which the strings are digitised is important. If the azimuth of a string segment, measured from point N to point N+1, is Ao and PLANMODE=1 or 2 then the true dip direction is calculated as A+90o or A+270o from strike. The XYZ coordinates of the mid-point of the string segment will be written to the output POINTS file together with the strike and true dip direction angles.

Section Strings

File SECTSTR contains strings digitised in vertical sections to define the dip. If parameter SECTMODE is set to 2 then the sections are oriented in the dip direction and so the dip will be the true dip of mineralisation and the orientation of the section line will be the true dip direction. Both these angle will be written to the output POINTS file together with the coordinates of the mid-point of the string segment. If SECTMODE is set to 1 then the sections are not oriented in the dip direction and so only the apparent dip can be calculated. In this case the sections must be parallel, so that they all have the same apparent dip direction. The apparent dip angle can then be interpolated into the model and process APTOTRUE used to convert from apparent to true dip. The direction in which the strings are digitised is important as the dip is measured for each string segment from point N to point N+1.

Wireframes

If parameter TRIPTS=1 the dip and dip direction of each triangle in the wireframe is calculated and written to the output POINTS file together with the coordinates of the centre of gravity of the triangle. The calculated angles are assumed to represent the true dip and true dip direction of the mineralisation. Calculating the angles from a wireframe is particularly suitable for narrow seams where the mineralisation follows the hangingwall and / or footwall, but is not so appropriate for massive deposits or narrow veins of irregular shape.

Input from wireframes and digitised strings can be used together. However in this case the string sections must be oriented in the dip direction so that true dip and true dip direction angles are calculated by both methods. All output is written to the single POINTS file.

ZONE Field

The ZONE field can be used to select a field in the wireframe triangle file which will be assigned to points in the output POINTS file. However this can only be used if the wireframe is a solid wireframe model. If parameter TRIPTS=1 and ZONE is specified then the wireframe will be used both to create points and to assign the ZONE field. If TRIPTS=0 then the wireframe will be used to assign the ZONE field to points derived from the plan and section strings, as done using the SELTRI process.

Attribute Fields

Attribute fields can be used to assign fields from the PLANSTR and SECTSTR files to the POINTS file. The attribute fields can then be used as Zone fields when the angles fields are estimated into the block model. The allows the estimates to be made in a single run of COKRIG or ESTIMA.

A set of up to 5 attribute fields can be defined for each point in the plan and section string files. If attributes are not defined then the orientation of each string segment is calculated and the angles are assigned to the mid-point of each segment and saved to file POINTS. If attributes are defined and the values of each attribute are the same at either end of a segment then the attribute values and angles are assigned to the mid-point of the segment. If one or more attributes do not have the same value at either end of the segment then the segment is split in half and the mid-point of each half segment is assigned the attributes of the nearer of the two segment ends. The half segment mid-points are also assigned the angle values.

The graphic below illustrates the assignment of attribute fields. Three strings from a SECTSTR file are coloured cyan. Each point in each string is annotated with numeric attribute value A1. Attribute values coloured brown are written to the POINTS file.

Two segments are displayed for the string on the right side of the graphic. The top and bottom of the first segment have A1 values of 1 so the top point will also have an A1 value of 1 (in brown). The second segment has an A1 value of 1 at the top and 2 at the bottom. As the A1 values are different the segment is split into two. The top half segment has an A1 value of 1 at its centre and the bottom half segment has an A1 value of 2 at its centre. The angles and attribute(s) of both points are written to the POINTS file.

The five symbolic fields PLNFLDi, i=1,5, will select attribute fields from the PLANSTR file. They will also select attribute fields with the same field name from the SECTSTR file. Similarly the five symbolic fields SCTFLDi, i=1,5, will select attribute fields from the SECTSTR file. They will also select attribute fields with the same field name from the PLANSTR file. It does not matter if an attribute field is selected twice.

Output Points File

The output POINTS file includes coordinate fields XPT, YPT and ZPT. It also includes a subset of four fields as shown in the table:

Field Description	True Dip Direction	True Dip	Apparent Dip Direction	Apparent Dip
Field Name	TRDIPDIR	TRDIP	APDIPDIR	APDIP
Wireframe	ü	ü	û	û
Plan	ü	û	û	û
Sections in dip direction	ü	ü	û	û
Sections not in dip direction	û	û	ü	ü

If parameter ADDSYMB=1 then a set of symbol fields are added. These have the reserved field names for displaying 3D symbols in a 3D window.

SYMBOL	Symbol code. The symbol is selected by parameter PLANSYMB for points created from plan strings, SECTSYMB for points created from section strings and WFSYMB for points created from wireframe triangles. Codes range from 201 to 267 which are shown in the graphic.
COLOUR	Colour of SYMBOL. This is defined by parameters PLANCOL, SECTCOL and TRICOL.
DIPDIRN	Field used to define the dip direction of the 3D SYMBOL. This is set equal to TRDIPDIR or APDIPDIR depending on whether true or apparent dips have been calculated.
SDIP	Field used to define the dip of the 3D SYMBOL. This field is set equal to TRDIP or APDIP depending on whether true or apparent dips have been calculated. For plans string data SDIP is set equal to 0 (horizontal).
SYMSIZE	Size of the symbol in mm as defined by parameter SYMSIZE.
DAANGLE 1/2/3	Additional fields provided if the ROTATION input is specified. Angles represent rotations around ZXZ.

If one or more Attribute fields have been defined then the following two fields will be included in the POINTS file:

PT_TYPE Point Type. This defines the source of the Point values:

PLAN_1 – single segment in PLANSTR file
PLAN_2 – first half segment in PLANSTR file
PLAN_3 – second half segment in PLANSTR file
SECT_1 – single segment in SECTSTR file
SECT_2 – first half segment in SECTSTR file
SECT_3 – second half segment in SECTSTR

COLOUR1 Colour field corresponding to PT_TYPE:

- 2 (PLAN_1), 3 (PLAN_2), 4 (PLAN_3), 5 (SECT_1), 6 (SECT_2), 7 (SECT_3)

Using Search Parameters or a Variogram Model as Inputs

If either a search volume parameters (SRCPARM) or variogram model (VMODEL) input are chosen (if both are selected, SRCPARM is used), an additional field is output - ANGLE3 which may be used in dynamic anisotropic calculations as a rotation around Z-X-Z (3-1-3).

If SRCPARM is specified, search distances must be listed in the input file in ascending order, for example, DIST1 > DIST2 > DIST3).
- If a search volume parameter file is specified, it must include a field SREFNUM which defines a unique reference number for each search volume. The SREFNUM parameter then defines which search volume will be used. If the SREFNUM parameter is set to absent data (the default), then the first search volume in the file will be used.
If VMODEL is specified, variogram ranges must be listed in ascending order.
- If a variogram model (VMODEL) is specified, then it must include a field VREFNUM which defines a unique reference number for each variogram model. The VMODEL parameter then defines which variogram model will be used. If the VREFNUM parameter is set to absent data (the default), then the first variogram model in the file will be used.

Minimum and Maximum Angles

If angles are derived from a wireframe then it is sometimes useful to specify minimum and maximum values for dip and dip direction. For example if the wireframe represents a seam and is endlinked then the triangles at either end can be eliminated. Similarly the triangles at the start and end of each section could be removed.

Input Files

Name	I/O Status	Required	Type	Description
PLANSTR	Input	No	String	Input strings, digitised in plan, defining the direction of the mineralisation.
SECTSTR	Input	No	String	Input strings, digitised in section, defining the dip and dip direction of the mineralisation.
WIRETR	Input	No	Wireframe Triangle	Input wireframe triangle file.
WIREPT	Input	No	Wireframe Points	Input wireframe points file.
SRCPARM	Input	No	Search Volume Parameters	Input search volume parameter file adding a dynamic ANGLE3 field when an input wireframe surface is used. Either a SRCPARM or VMODEL should be selected; if both are selected the SRCPARM will be used. This file must contain the fields SREFNUM, SANGLE1, SANGLE2, SANGLE3, SAXIS1, SAXIS2, SAXIS3, SDIST1, SDIST2, and SDIST3, which define the orientation and dimensions of the search volume. Search distances must be in descending order, with SDIST1 >= SDIST2 >= SDIST3.
VMODEL	Input	No	Variogram model	Input variogram model file for adding a dynamic ANGLE3 field when an input wireframe surface is used. Either a SRCPARM or VMODEL should be selected; if both are selected only the SRCPARM will be used and the VMODEL will be ignored. This file must contain the fields VREFNUM, VANGLE1, VANGLE2, VANGLE3, VAXIS1, VAXIS2, VAXIS3, ST1, ST1PAR1, ST1PAR2 and ST1PAR3 (for up to 10 structures) which define the orientation and dimensions of the variogram model. Variogram ranges must be in descending order.
ROTATION	Input	No	Variogram model or Search Parameter file	Input file (variogram model or search parameter) containing a rotation for aligning input wireframe. Including this option will output an additional three angles [DAANGLE1, DAANGLE2, DAANGLE3] rotated around the axes ZXZ (313) in the output points which may be used for Dynamic Anisotropy with the input search or variogram model rotation. This option will also output a rejected points containing points that fall outside the specifed THRESH1 and THRESH2

Output Files

Name	I/O Status	Required	Type	Description
POINTS	Output	Yes	Points	Output points file including fields SDIP, DIPDIRN, SYMBOL and SYMSIZE.

Fields

Name	Description	Source	Required	Type	Default
ZONE	Optional field in input wireframe triangle file used to identify individual solid models. The field will be assigned to points in the output POINTS file.	WIRETR	No	Any	Undefined
PLNFLD1 - 5	Attribute field in PLANSTR file to be added to POINTS file	PLANSTR	No	Any	Undefined
SCTFLD1 - 5	Attribute field in SECTSTR file to be added to POINTS file	SECTSTR	No	Any	Undefined

Parameters

Name	Description	Required	Default	Range	Values
TRIPTS	Flag to indicate whether the output points file should include points from triangles. Default 1. 0 = Do not create points from triangles. The wireframe is only used for assigning the ZONE field. 1 = Create points from triangles	No	1	0,1	0,1
PLANMODE	Flag to indicate how the dip direction is calculated from strings that have been digitised in plan. Default 1. 1 = String represents strike direction, and dip direction is 90 degrees to the direction of strike. 2 = String represents strike direction, and dip direction is 270 degrees to the direction of strike. 3 = String represents the dip direction.	No	1	1,3	1,2,3
SECTMODE	Flag to indicate whether sections are parallel to the dip direction, thus giving true dips. Default 1. 1 = Sections are not parallel to the dip direction, so apparent dips are calculated. 2 = Sections are parallel to the dip direction, so true dips are calculated.	No	1	1,2	,2
MINDIP	Minimum value (in degrees) of dip angle to be written to the output points file. If a value less than the minimum is calculated it will be rejected. Default -90.	No	-90	-90,90	Undefined
MAXDIP	Maximum value (in degrees) of dip angle to be written to the output points file. If a value greater than the maximum is calculated it will be rejected. Default +90.	No	90	-90,90	Undefined
MINDIRN	Minimum value (in degrees) of dip direction angle to be written to the output points file. If a value less than the minimum is calculated it will be rejected. Angles are calculated from minimum to maximum in a clockwise direction. Hence a minimum of 330o and a maximum of 20o will define a window of 50o. If MINDIRN is not defined, or set to absent, it will not be used. If MINDIRN is defined it must lie between 0o and 360o. Both MINDIRN and MAXDIRN must be specified in order for limits to be applied. The default is absent data, so limits will not be applied.	No	Undefined	0,360	Undefined
MAXDIRN	Maximum value (in degrees) of dip direction angle to be written to the output points file. If a value greater than the maximum is calculated it will be rejected. Angles are calculated from minimum to maximum in a clockwise direction. Hence a minimum of 330o and a maximum of 20o will define a window of 50o. If MAXDIRN is not defined, or set to absent, it will not be used. If MAXDIRN is defined it must lie between 0o and 360o. Both MINDIRN and MAXDIRN must be specified in order for limits to be applied. The default is absent data, so limits will not be applied.	No	Undefined	0,360	Undefined
ADDSYMB	Flag to indicate whether symbol fields SYMBOL, COLOUR, DIPDIRN, SDIP and SYMSIZE should be added to the output POINTS file. 0 = Do not add symbol fields to POINTS file. 1 = Add symbol fields to POINTS file.	No	0	0,1	0,,1
PLANSYMB	Symbol code to select symbol to be displayed for points derived from digitised plans. Valid values are 201-267. Symbols are shown in the Full Description.	No	216	201,276	Undefined
SECTSYMB	Symbol code to select symbol to be displayed for points derived from digitised sections. Valid values are 201-267. Symbols are shown in the Full Description.	No	216	201,276
WFSYMB	Symbol code to select symbol to be displayed for points derived from wireframe triangles. Valid values are 201-267. Symbols are shown in the Full Description.	No	224	201,276	Undefined
PLANCOL	Colour assigned to symbol to be displayed for points derived from digitised plans.	No	1	1,64	Undefined
SECTCOL	Colour assigned to symbol to be displayed for points derived from digitised sections.	No	2	1,64	Undefined
WFCOL	Colour assigned to symbol to be displayed for points derived from wireframe triangles.	No	3	1,64	Undefined
SYMSIZE	Symbol size in mm.	No	2	0,50	Undefined
SREFNUM	If a search volume parameter file (SRCPARM) is specified, then it must include a field SREFNUM which defines a unique reference number for each search volume. The SREFNUM parameter then defines which search volume will be used. If the SREFNUM parameter is set to absent data (the default), then the first search volume in the file will be used.	No	1	Undefined	Undefined
VREFNUM	If a variogram model (VMODEL) is specified, then it must include a field VREFNUM which defines a unique reference number for each variogram model. The VMODEL parameter then defines which variogram model will be used. If the VREFNUM parameter is set to absent data (the default), then the first variogram model in the file will be used.	No	1	Undefined	Undefined

Example

!ANISOANG &PLANSTR(_VSPLNST),&SECTSTR(_VSSECST),&POINTS(POINTS1),

@TRIPTS=1.0,@PLANMODE=2.0,@SECTMODE=1.0,@ADDSYMB=1.0,

@PLANSYMB=216.0,@SECTSYMB=216.0,@WFSYMB=224.0,@PLANCOL=1.0,

@SECTCOL=2.0,@WFCOL=3.0,@SYMSIZE=3.0

ANISOANG
... creating points from plan strings
... creating points from section strings
Dip direction of section strings (APDIPDIR) = 90
Angle creation complete
- Points file POINTS1 created with 403 records