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iMOD User Manual version 5.2 (html)


8.2IDF-FUNCTIONS


8.2.1IDFCALC-Function

The IDFCALC function can be used to carry out simple arithmetical operations on maximal two different IDF-files to create a new IDF-file. See for more information section 6.7.3.

FUNCTION=

IDFCALC

FUNC=

Enter the function, e.g. C=A-B or C=ABS(A-3.0*B), or C=A, see section 6.7.3 for more information. Whenever the symbol “/” is used, apply quotes, thus “C=A/B”.

ABC{i}=

Enter the i\({}^{th}\) out of NREPEAT IDF-filenames that corresponds with “A”, “B” and “C” in the function FUNC.

AC{i}=

Enter the i\({}^{th}\) out of NREPEAT IDF-filename that corresponds with “A” and “C” in the function FUNC.

BC{i}=

Enter the i\({}^{th}\) out of NREPEAT IDF-filename that corresponds with “B” and “C” in the function FUNC.

NREPEAT=

Specify the number of times the function FUNC need to be carried out.

SOURCEDIRA=

Enter a folder that contains all the IDF-files associated to the “A” in FUNC. Apply this keyword whenever NREPEAT is absent.

SOURCEDIRB=

Enter a folder that contains all the IDF-files associated to the “B” in FUNC. Apply this keyword whenever NREPEAT is absent.

SOURCEDIRC=

Enter a folder that contains all the IDF-files associated to the “C” in FUNC. Apply this keyword whenever NREPEAT is absent.

USENODATA=

Enter USENODATA=1 to use cells that have NoDataValues. By default, USENODATA=0, so those cells that have NoDataValue will be ignored.

NODATAVALUE

Enter the value for the NoDataValue to be used in the computation, e.g. NODATAVALUE=0.0. This keyword is compulsory whenever USENODATA=1.

GENFILE=

Enter the name of a GEN-file, e.g. GENFILE=D:\DATA\AREA.GEN. Any computation will be carried out inside the polygons of the GENFILE. On default, GENFILE=’ ’, which means that no genfile will be used.

IEQUI=

Enter IEQUI=0 to construct (if needed) a non-equidistant IDF-file that counts for all raster dimensions of the entered IDF-files, this is the default. Enter IEQUI=1 to force that the resulting IDF-files are produced with equidistant cellspaces, based on the smallest cell size occurring in the IDF-files “A” and/or “B”.

WINDOW=

Enter the coordinates of the window that need to be computed, solely. Enter coordinates of the lower-left corner first and then the coordinates of the upper-right corner, e.g. WINDOW=100000.0, 400000.0, 200000.0, 425000.0. When WINDOW= is absent, the entire dimensions of the first mentioned IDF-file will be used.

TRIM_VALUE=

Enter a value to be able to ignore all result values smaller than this specific absolute value after the calculation. This option gives values smaller than given/entered absolute value a NodataValue, e.g. C=A-B if C\(<0.1\) C=NodataValue.

Example 1

FUNCTION=IDFCALC
FUNC= “C=A/B”
NREPEAT=2
ABC1=D:\KD_L1.IDF D:\THICKNESS_L1.IDF D:\K_L1.IDF
ABC2=D:\KD_L4.IDF D:\THICKNESS_L4.IDF D:\K_L4.IDF

The above mentioned example will compute the permeability (k) by dividing the transmissivity (KD) by the thickness (THICKNESS) for modellayer 1 and modellayer 4, subsequently.

Example 2

FUNCTION=IDFCALC
FUNC= C=A-B
USENODATA=1
NODATAVALUE=0.0
IEQUI=1
GENFILE=D:\AREA.GEN
WINDOW=100000.0,350000.0,150000.0,450000.0
SOURCEDIRA=D:\MODEL\HEAD_*_L1.IDF
SOURCEDIRB=D:\SCENARIO\HEAD_*_L1.IDF
SOURCEDIRC=D:\EFFECT\DIFF_*_L1.IDF

The above mentioned example will compute the differences within the polygon(s) described by the AREA.GEN and within the given WINDOW. If any NoDataValues are found in the IDF-files, they will be treated as if they were NODATAVALUE=0.0. Any file that agrees with the filename HEAD_*_L1.IDF in two different folders, D:\MODEL and D:\SCENARIO will be subtracted and the results will be saved, as an equidistant IDF, in the folder D:\EFFECT. Suppose HEAD_20101231_L1.IDF is found in D:\MODEL (SOURCEDIRA), an identical filename is searched for in D:\SCENARIO (SOURCEDIRB). The yielding IDF will be DIFF_20101231_L1.IDF and will be written in D:\EFFECT.

Example 3: batch-array definition

setlocal EnableDelayedExpansion
set n=0
for %%a in (1.30 0.80 0.70 0.75 0.85 1.25 0.75 0.75 0.85 1.10 1.15 ) do (
set RCH_factor[!n!]=%%a
set /A n+=1
)

setlocal EnableDelayedExpansion
set n=0
for %%a in (1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001) do (
set year[!n!]=%%a
set /A n+=1
)

for /L %%i in (0,1,11) do (
echo FUNCTION=IDFCALC >calc_idf.ini
echo !RCH[%%i]!
echo FUNC= ”C=!RCH_factor[%%i]!*A” >>calc_idf.ini
echo SOURCEDIRA=d:\RCH_grids\RCH_averaged_1990-2001.idf >>calc_idf.ini
echo SOURCEDIRC=d:\RCH_grids\RCH_!year[%%i]!.idf >>calc_idf.ini newline This example uses multiple arrays to end up with one recharge grid per year based on a given recharge factor.


8.2.2IDFSCALE-Function

With this function it is possible to (re)scale IDF-files according to different methodologies, see section 6.7.3.

FUNCTION=

IDFSCALE

SCALESIZE=

Enter the cell size of the upscaled or downscaled IDF-file(s), e.g. SCALESIZE=100.0 meaning that the cellsize of the resulting IDF-file(s) will be 100 square meter uniformly.

The keyword SCLTYPE_UP and SCLTYPE_DOWN may be specified both because it is possible to execute upscaling and downscaling in one action on IDF’s containing different scales. In case SCLTYPE _UP and/or SCLTYPE_DOWN are not specified than default values are used, for SCLTYPE _UP: 2 and for SCLTYPE_DOWN: 1.

SCLTYPE_UP

Enter the scale type. Choose from the following:

  • • 1: boundary scaling (rule: minus values above positive values x above zero values);

  • • 2: arithmetic scaling (rule: sum n-values x within coarse cell, excluding the NoDataValues, and divide them by n);

  • • 3: geometric scaling (rule: take log()-function for n-values x within a coarse cell, excluding NoDataValues and zero values, sum them, divide them by n and take the exp() function);

  • • 4: sum (rule: sum n-values x, excluding NoDataValues);

  • • 5: sum conductance (rule: sum n-values times ratio values to calculate the average conductance over cells for upscaled cell.);

  • • 6: inverse (rule: take the inverse (x\({}^{-1}\)) of n-values x within a coarse cell, excluding NoDataValues and zero values and divide them by n;

  • • 7: most frequent occurrence (rule: take that value x that occurs mostly within a coarse cell, excluding NoDataValues);

  • • 8: sum inverse (rule: take the inverse (x\({}^{-1}\)) of n-values x within a coarse cell, excluding NoDataValues and zero values);

  • • 9: percentile (rule: take the value x that occurs for a given percentage within a coarse cell, excluding NoDataValues);

  • • 10: block value (rule: takes the center value of the cells that needs to be upscaled.);

  • • 11: Darcian method (rule: take the value x that occurs after a Darcian simulation of fine mesh with extent of the coarse cell, excluding NoDataValues);

  • • 12: homogenization (rule: take the value x that occurs after a Darcian simulation with periodic boundaries of fine mesh with extent of the coarse cell, excluding NoDataValues);

  • • 13: global-local method (rule: take the value x that occurs after a Darcian simulation with realistic boundary conditions of fine mesh with extent of the coarse cell, excluding NoDataValues);

  • • 14: 3D simulations (rule: Calculates with a 3-D numerical model the Darcian flows to determine the upscaled permeability model per cell;

  • • 15: zonation (rule: Calculates an upscaled value as the most frequent value for the integer values within the coarse grid cell, and the fraction as the averaged fraction, while ignoring those cells that do not coincide with the upscaled integer value (e.g. \(x_1\)=1.5; \(x_2\)=2.25 and \(x_3\)=1.4, means that the most frequent integer is 1, and the average fraction for 1 is (0.5+0.4+0.0)/3=0.3, so the final value is 1.3).

SCLTYPE_DOWN=

Enter the scale type. Choose from the following:

  • • 1: interpolation (rule: produces a good guess for al finer gridcells by a linear interpolation based on the coarse gridcells, excluding the NoDataValues);

  • • 2: gridvalues (rule: assign the value of the coarse gridcell to all finer gridcells).

SOURCEIDF

Enter the name of the IDF-file to be upscaled or downscaled, e.g. SOURCEIDF=D:\DATA\TRANSMISSIVITY.IDF.

OUTFILE

Enter the name of the upscaled or downscaled IDF-files, e.g. OUTFILE=D:\DATA\SCALED_TRANSMISSIVITY.IDF.

PERCENTILE=
(SCLTYPE_UP=9)

Enter a percentile, e.g. PERCENTILE=0.5 (0.0\(<\)PERCENTILE\(<\)1.0). This keyword is obliged whenever SCLTYPE=9.

WEIGHFACTOR=
(SCLTYPE_UP=1,3,4,5,6,9)

Enter a weight factor, e.g. WEIGHFACTOR=0.5. This keyword is optional in case SCLTYPE in {1,3,4,5,6,9}, the default value is WEIGHFACTOR=1.0.

BLOCK=
(SCLTYPE_DOWN=1)

Enter the size of the interpolation block, e.g. BLOCK=16. This keyword is optional for SCLTYPE_DOWN=1, meaning that a matrix of 4x4 will be used for the interpolation of each point. The default value is BLOCK=4 and other possible values are BLOCK in {4,16,36,64,100). In most situation good results are obtained with BLOCK=4.

WINDOW=
(optional)

Enter the coordinates of the window that need to be computed, solely. Enter coordinates of the lower-left corner first and then the coordinates of the upper-right corner, e.g. WINDOW=100000.0, 400000.0, 200000.0, 425000.0. When WINDOW= is absent, the entire dimensions of the first mentioned IDF-file will be used.


The following are keywords that are optional in case SCLTYPE=14, solely.

Illustration of the 3D simulations to determine the upscaled permeabilities.
pictures/h6-h71/scale14.png

SOURCEDIR=

Enter the name of the folder that contains IDF-files that need to be used for a 3D simulation, e.g. SOURCEDIR=D:\DATA\K*.IDF.

TOPTRIMIDF=

Enter the name of an IDF file that represents the top of the column to determine an upscaled permeability, e.g. TOPTRIMIDF=D:\DATA\TOP.IDF.

BOTTRIMIDF=

Enter the name of an IDF file that represents the bottom of the column to determine an upscaled permeability, e.g. BOTTRIMIDF=D:\DATA\BOT.IDF.

BUFFER=
(optional)

Enter the size of the buffer to be used for the Darcian simulation, BUFFER=5 (SCLTYPE in {9,10,11,12}). The default value is BUFFER=0.

ANI_X=
ANI_Z=
(optional)

Enter the horizontal (ANI_X) or vertical (ANI_Z) anisotropy, e.g. ANI_Z=0.3. This means that the permeability will be 3 time less permeable in vertical direction than in horizontal direction. Default value is ANI_X=ANI_Z=1.0.

DH_X=
DH_Y=
DH_Z=
(optional)

Enter the pressure for the x, y and z direction to be imposed on the system, e.g. DH_X=1.0. This means that the hydraulic pressure difference along the x direction is equal to meter. By default DH_X=DH_Y=DH_Z=0.0. These keyword are not used whenever QRATE is specified.

ILGROUP=
(optional)

Enter a value for the amount of layers that will be taken into account to find the representative top- and bottom at which a clay-layer starts and ends. Suppose, ILGROUP=2, the function searched for the layers \(i-2\) up to \(i+2\). If the average k-value for this 3-D box is less or equal KMIN, the clay-body start- or ends. BY default ILGROUP=1.

KMIN= (optional)
Enter a value that represents the minimal K-value. This value accounts for the upper- and lower-boundaries of the clay-layer within the voxels. This is optional and its default value is KMIN=1.0 m/day.

FILLNODATA=
(optional)

Enter FILLNODATA=1 to substitute for those cells that contain NoDataValues their values with MAX_K. By default FILLNODATA=0.

MAX_K= (optional)
Specify the permeability to be used to substitute cells with NoDataValues. The default value is MAX_K=250 m/day.

QRATE=
(optional)

Enter the strength of a extraction well positioned in the lower most model layer, e.g. QRATE=-100 m\({}^{3}\)/day. By default QRATE=0.0, however, in those case where QRATE\(<\)\(>\)0.0, DH_X, DH_Y and DH_Z will be ignored.

AQFR_KD= (optional)
Enter the transmissivity to be used to the lower-most model layer in the simulation which contains an extraction. This keyword is necessary only in combination with QRATE. The default value is 250 m\(^2\)/day.

HCLOSE=
(optional)

Enter the closure criterion for hydraulic heads (meter). By default HCLOSE is MAX(DH_X,DH_Y,DH_Z)/1000.0 which is appropriate for most simulations.

RCLOSE=
(optional)

Enter the closure criterion for hydraulic heads (meter). By default RCLOSE is defined as CS\(^2\)/100.0 where CS is the cell size of the input file IDF files.

Example 1

FUNCTION=IDFSCALE
SCLTYPE_UP=1
SCALESIZE=250.0
SOURCEIDF=D:\DATA\BOUNDARY_L1.IDF
OUTFILE=D:\DATA\BOUNDARY_L1_250.IDF

This example shows how to upscale an IDF-file with boundary conditions.

Example 2

FUNCTION=IDFSCALE
SCLTYPE_DOWN=1
SCALESIZE=5.0
SOURCEIDF=D:\DATA\HEAD_STEADY-STATE_L1.IDF
OUTFILE=D:\DATA\HEAD_STEADY-STATE_L1_5X5.IDF

This example shows how to downscale an IDF-file with computed heads.

Example 3

FUNCTION=IDFSCALE
SCLTYPE_UP=3
SCALESIZE=500.0
WINDOW=100000.0,425000.0,150000.0,500000.0
SOURCEIDF=D:\DATA\HEAD_STEADY-STATE_L1.IDF
OUTFILE=D:\DATA\HEAD_STEADY-STATE_L1_500.IDF

This example shows how to upscale transmissivity for a specific window.

Example 4

FUNCTION=IDFSCALE
SCLTYPE_UP=14
SCALESIZE=100.0
SOURCEDIR=D:\GEOTOP\SEL*.IDF
OUTFILE=D:\GEOTOP\VERTICAL_C.IDF
BUFFER=5
ANI_X=3.0
DH_Z=1.0
DH_X=0.0
DH_Y=0.0

This examples show an example how to upscale permeability with a 3D Darcian simulation. The result will be vertical resistances.


8.2.3IDFMEAN-Function

The IDFMEAN function can be used to compute a new IDF-file with the mean value (or minimum, maximum value) of different IDF-files. It is not necessary to have exactly similar IDF-files (see section 6.7.3).

FUNCTION=

IDFMEAN

NDIR=

Enter the number of folders to be processed repeatedly, e.g. NDIR=10.

SOURCEDIR{i}=

Enter the folder and wildcard for all files that need to be used, e.g. SOURCEDIR1=C:\DATA\DEM\VERSION*.IDF. Repeat SOURCEDIR{i} for NDIR times.
iMOD supports the selection of original model output files that meets the unique definition of output files: {Topic name}_YYYYMMDD_L{layer number}, e.g. SOURCEDIR1=C:\DATA\BDGFLF*.IDF. Do not include year, month, day or layer before or after the wildcard *. This option is activated whenever ILAYER is specified.

CFUNC=

Specify the name of the function to be applied. Choose out of:
MEAN, to compute mean values (equal weighed);
MIN to compute the minimum values;
MAX to compute the maximum values.
SUM to compute the sum of the values per grid cell;
PERC to compute the median value (50 percentile).
The default is CFUNC=MEAN.

PERCVALUE=
(optional)

Specify a percentile whenever CFUNC=PERC, e.g. PERCVALUE=50.0 for median values.

ILAYER=
(optional)

Enter the layer numbers for the IDF-files to be averaged on one line, e.g. ILAYER=1,3,5,6,10.

SDATE= (optional)
Enter the starting date (yyyymmdd) for which IDF-files are used, e.g. SDATE=19980201. This keyword is obligate whenever ILAYER is specified.

EDATE= (optional)
Enter the ending date (yyyymmdd) for which IDF-files are used, e.g. EDATE=20111231. This keyword is obligate whenever ILAYER is specified.

IYEAR= (optional)
Specify particular year (within SDATE and EDATE) to be used exclusively, e.g. 2001,2003,2005. IYEAR is filled in for all years in-between SYEAR and EYEAR.

NPERIOD= (optional)
Enter a number of periods to be defined to use IDF-file within these periods solely, e.g. NPERIOD=2. NPERIOD=0 by default.

PERIOD{i}= (optional)
Enter a period i (ddmm-ddmm), e.g. PERIOD1=1503-3110 to express the period 15\({}^{th}\) of March until the 31\({}^{th}\) of October. This keyword is obligate whenever NPERIOD is specified.

ISEL=
(optional)

Enter a code for the area to be processed:
ISEL=1 will compute the entire region
ISEL=2 will compute within given polygons;
ISEL=3 will compute for those cells in the given IDF-file that are not equal to the NoDataValue of that IDF-file.

GENFNAME=
Enter a GEN-filename for polygon(s) for which mean values need to be computed. This keyword is obliged whenever ISEL=2.

IDFNAME=

Enter an IDF-file for which mean values will be computed for those cell in the IDF-file that are not equal to the NoDataValue of that IDF-file. This keyword is compulsory whenever ISEL=3

OUTFILE=

Enter the name of an output file to overrule the default folder and file names (see the examples below), e.g. OUTFILE= D:\PROCESSING\SELECTION1.IDF.
The second output file for this function, containing the number of used cells in the calculation, will be named SELECTION1_COUNT.IDF.
In case CFUNC=MIN or MAX and the source files have the model result file format (ILAYER, SDATE and EDATE are obligate), the second output file gets the string ”_DATE” attached to the OUTFILE name.

Example 1

FUNCTION=IDFMEAN
NDIR=1
SOURCEDIR1=C:\DATA\DEM\VERSION*.IDF

This example shows the minimum configuration of this function. It yields 2 IDF files in the folder C:\DATA\DEM\:

Example 2

FUNCTION=IDFMEAN
ILAYER=6
SDATE=19980714
EDATE=20110728
NDIR=1
SOURCEDIR1=C:\DATA\BDGFLF*.IDF

This example shows the mimimum configuration of this function and yield the MEAN values (default) for all BDGFLF*.IDF-files in the folder C:\DATA that are assigned to layer 6 (function searches for L6.IDF), and are within the periode 14\({}^{th}\) of July 1998 and 28\({}^{th}\) of July 2011.

The output file will be:

The latter shows the number of occurrences for each raster cell.

Example 3

FUNCTION=IDFMEAN
ILAYER=1,3
SDATE=19980101
EDATE=20000101
IYEAR=1999
NPERIOD=1
PERIOD1=1503-3110
ISEL=2
CFUNC=MAX
GENFILE=D:\DATA\AREA.GEN
NDIR=1
SOURCEDIR1=D:\DATA\HEAD*.IDF

This example shows a more extended configuration and will yield maximum values for all IDF-files inside the folder D:\DATA that meet the requirement HEAD*.IDF. Furthermore, they contain the key combination L1.IDF where “1” is defined by ILAY=1. The date expression should be within the time domain of the 1\({}^{th}\) of Januari 1998 (SDATE) and 31\({}^{th}\) of December 2000 (EDATE), within the year 1999 (IYEAR) and within the period between the 15\({}^{th}\) of March and the 31\({}^{th}\) of October (PERIOD1). Finally the mean values is computed within the polygon(s) described by the polygon AREA.GEN, solely. The output file will be:

The latter shows the date (yyyymmdd) on which raster cell maximal values appeared.


8.2.4IDFCONSISTENCY-Function

Use this function to make IDF-files consistent, meaning that the first IDF is always higher or equal to the second, which is higher or equal to the top of the IDF underneath, and so on. IDF files can represent anything, however, this tool is especially handy for consistencies applied on top- and bottom elevation of model layers.

FUNCTION=

IDFCONSISTENCY

NLAY=

Enter the number of model layers, e.g. NLAY=6.

TOP_L{i}=

Enter the IDF for the i\({}^{th}\) modellayer that represents the top of modellayer i, e.g. TOP_L1=D:\INPUT\TOP_L1.IDF. Constant value may be entered as well, e.g. TOP_L1=10.0.

BOT_L{i}=

Enter the IDF for the i\({}^{th}\) modellayer that represents the bottom of modellayer i, e.g. BOT_L1=D:\INPUT\BOT_L1.IDF. Constant value may be entered as well, e.g. BOT_L2=-43.12.

OUTPUTFOLDER=

Enter the foldername in which the adjusted IDF-files will be saved, e.g. OUTPUTFOLDER=D:\RESULT. Whenever a file is entered by a constant value, e.g. TOP_L1=23.32, a file will be created called TOP_L1.IDF that represents the (corrected) value.

ICLEAN=

Enter an option for the cleaning of the IDF files. The following options for ICLEAN are available:

  • 0
    By default ICLEAN=0 which mean that only consistency corrections are applied for cells not equal to their NodataValues;

  • 1
    Whenever ICLEAN=1 the procedure removes all data in all files whenever at least a single NodataValue is found among them at that specific location;

  • 2
    Whenever ICLEAN=2 it removes all data whenever at least a NodataValue is found for the first and second idf file at that specific location;

  • 3
    Whenever ICLEAN=3, it filled in NodataValues with values from the first NodataValue from underlying IDF files.

WINDOW=

Enter the coordinates of the window that needs to be computed. Enter coordinates of the lower-left corner first and then the coordinates of the upper-right corner, e.g. WINDOW=100000.0, 400000.0, 200000.0, 425000.0. When WINDOW= is absent, the entered IDF-files by TOP_L{i} and BOT_L{i} need to be equally in their dimensions. Otherwise they will be upscaled (mean) or downscaled (interpolation) to the entered CELLSIZE.

CELLSIZE=

Enter the cell size (meter) for the IDF-files that will be created, e.g. CELL_SIZE=25.0.

MINLAY_THICKNESS=

Enter the minimum layer thickness to be applied for the permeable layers in the model. Only the layers between the TOP and BOT of the same layer are taken into account, e.g. MINLAY_THICKNESS=0.10; in case the layer thickness of the second modellayer (THICKNESS_L2=TOP_L2-BOT_L2) is smaller then 0.10 m the TOP_L2 will be corrected, so the thickness of layer 2 becomes 0.10 m.

MINLTZERO_OPT

Enter this option when it is preferred to apply the given minimal layer thickness (defined with “MINLAY_THICKNESS”) also to layers that have a thickness of 0.0 m. By default this option is set to 0, which means that layers with a layer thickness equal to zero will not be corrected.

Example

FUNCTION= IDFCONSISTENCY
NLAY=2
WINDOW=120000.0,298000.0,240000.0,430000.0
CELLSIZE=100.0
TOP_L1=D:\MODEL\TOP_L1.IDF
TOP_L2=D:\MODEL\TOP_L2.IDF
BOT_L1=D:\MODEL\BOT_L1.IDF
BOT_L2=D:\MODEL\BOT_L2.IDF
OUTPUTFOLDER=D:\OUTPUT

This example corrects the top and bottom IDF-files specified by the TOP_L{i} and BOT_L{i} keywords in a top-bottom consistent manner and scales the IDF-files to the specified WINDOW and CELL_SIZE.


8.2.5IDFSTAT-Function

The IDFSTAT function can be used to perform some elementary statistical analyses on the content of IDF-files. You can use the IDF Info functionality in iMOD, alternatively (see section 6.3).

FUNCTION=

IDFSTAT

SOURCEDIR=

Enter the name of a folder that contains a specific set of IDF-file(s), e.g. {installfolder}:\DATA\RESULTS\HEAD*.IDF. All IDF-files that agree, will be included in the analysis.

IFORMAT
(optional)

Select the type of output desired, e.g. IFORMAT=1. Default value is IFORMAT=0. See for the differences in output format at the description of OUTFILE.

OUTFILE=

Specify a filename for the resulting statistical analysis, e.g. {installfolder}\DATA\RESULTS\RESULT.CSV. A result of this can look as (IFORMAT=0):

1,AHN.IDF
2,AHN_FILTERED.IDF
3,AHN_SCALED.IDF
File, Population, Mean, Variance, P( 0), …, P(100)
1, 585917, 9.2359428, 0.0248852, -6.8000002, …, 4.0799999
2, 40000, 1.9279687, 0.0015057, -0.1490000, …, 2.9757273
3, 147912, 9.2729473, 0.0498930, -6.7449999, …, 335.730011

All percentiles will be computed between 0 and 100 by steps of 5.

The output format can also look as (IFORMAT=1):

File, Population, Mean, Variance, Min, Max, Median
AHN_1 , 585917, 9.2359428, 0.0248852, -6.8000002, 4.0799999, -0.324343
AHN_2, 40000, 1.9279687, 0.0015057, -0.1490000, 2.9757273, 1.35984
AHN_3, 147912, 9.2729473, 0.0498930, -6.7449999, 335.730011, 87.32234

Example 1

FUNCTION=IDFSTAT
SOURCEDIR=D:\DATA\AHN*.IDF
OUTFILE=D:\DATA\STAT.CSV

This examples illustrated how to get the statistics of all IDF-files inside the folder D:\DATA that agree with the wildcard AHN*.IDF; results will be written in the file D:\DATA\STAT.CSV.


8.2.6IDFMERGE-Function

The MERGE function can be used to merge different IDF-files into a new IDF-file. If these IDF-files might overlap, an interpolation between the overlapping IDF-files will be carried out.

FUNCTION=

IDFMERGE

NMERGE=

Enter the number of IDF-files that need to be merged, e.g. NMERGE=6.

SOURCEIDF{i}=

Enter the i\({}^{th}\) IDF-file, e.g. SOURCEIDF1=D:\SUBMODEL1\HEAD_L1.IDF, SOURCEIDF2= D:\SUBMODEL2\HEAD_L1.IDF. Repeat this keyword NMERGE-times. Whenever NMERGE is absent, the keyword SOURCEDIR will be used.

SOURCEDIR=

Enter the source folder and part of the filename that need to be merged, e.g. D:\DATA\HEAD*L1.IDF to merge all files that corresponds to this wildcard. This keyword SOURCEDIR is used whenever the keyword NMERGE is absent.

TARGETIDF=

Specify a filename for the resulting IDF-file, e.g.
{installfolder}\TOTAL\HEAD_L1.IDF.

WINDOW=

Specify a window in which the entered IDF-files (SOURCEIDF{i}, SOURCEDIR) will be merged only. Enter coordinates of the lower-left corner first and then the coordinates of the upper-right corner, e.g. WINDOW=100000.0, 400000.0, 200000.0, 425000.0. When WINDOW= is absent, the total dimension of all selected IDF-files in the SOURCEDIR will be used.

MASKIDF=

Enter an IDF-file that needs to be mask areas (those with values equal to the NoDataValue in the MASKIDF) in the merged results, e.g. D:\MASK\AREA.IDF.

Example 1

FUNCTION=IDFMERGE
NMERGE=2
SOURCEIDF1=D:\MODEL1\HEAD_L1.IDF
SOURCEIDF2=D:\MODEL2\HEAD_L1.IDF
TARGETIDF=D:\RESULT\HEAD_L1.IDF

This example merges two IDF-files, HEAD_L1.IDF and HEAD_L1.IDF from two different folders, into a single one D:\RESULTS\HEAD_L1.IDF.

Example 2

FUNCTION=IDFMERGE
MASKIDF=D:\MASK\AREA.IDF
WINDOW=120000.0,425000.0,165000.0,465000.0
SOURCEDIR=D:\DATA\HEAD*_L1.IDF
TARGETIDF=D:\DATA\HEAD_MERGED_L1.IDF

This example merges all IDF-files in the folder D:\DATA that agree with the filename HEAD*_L1.IDF, such as HEAD_A1_L1.IDF, HEAD_A2_L1.IDF. The merged results will be “clipped” for the given extent by WINDOW and will be “masked” out by the given NoDataValues in the MASKIDF. Finally the results will be saved in HEAD_MERGED_L1.IDF.


8.2.7IDFTRACE-Function

Use this function to make a spatial IDF file with unique zone numbers of non-connecting areas of a given IDF file.

FUNCTION=

IDFTRACE

IDF_IN=

You can enter the IDF file with the areas, e.g. IDF_IN=D:\DATA\LAKES.IDF. All values greates than 0.0 will be processed.

IDF_OUT=

You can enter the output IDF file with areas numbered uniquely, e.g. IDF_OUT=D:\DATA\LAKES_ID.IDF.

MINT=
(optional)

Enter the minimal size of the aggregated areas to be numbered, e.g. MINT=10. By default MINT=0 and all locations with values greater than 0.0 will be used to create a numbered zone, if you enter MINT=10, only areas that are aggregated to be more than 10 locations will be numbered.

Example

FUNCTION=IDFTRACE
IDF_IN=D:\DATA\LAKE.IDF
IDF_OUT=D:\DATA\LAKE_ID.IDF
MINT=10

This example creates an IDF file that can be used by the Lake package for the identification of indivual lakes, larger than 10 gridcells from the entered IDF file at IDF_IN.


8.2.8CREATEIDF-Function

The CREATEIDF function can be used to create IDF-files out of ESRI ASC File Formats, see section 9.14. Be aware of the fact that you can open more of these ASC files in the iMOD Manager, alternatively (see section 5.4).
This function includes the option to make IDF files with a VOXEL representation. See section 6.3 for an example. (There is no option yet to transform an existing IDF into a VOXEL IDF. In that case, create an ASC file first)

FUNCTION=

CREATEIDF

SOURCEDIR=

Enter the name of a folder that contains a specific set of ASC file(s), e.g. {installfolder}\DATA\RESULTS\HEAD*_L*.ASC.
All ASC files that agree will be converted to IDF-files.
It is compulsory to fill in a complete path rather than a relative path.

TOPWC=
(optional)

Enter the wildcard that specifies the part of the filename that represents the top elevation of the data, e.g. SEL_*.ASC. In this case, iMOD will search for the absolute top elevation to be defined at the location of the asterix, e.g. SEL_0.40.ASC will yield the value 0.40.

BOTEL=

Enter the relative bottom of the elevation to be added to the top elevation, e.g. BOTEL=-0.50 will yield an absolute bottom elevation of 0.40-0.50=-0.10.

ADD=
(optional)

Enter a value to add to the top and the bottom elevation (TOP and BOT), e.g. ADD=3.0, TOP=TOP+3.0.

MULT=
(optional)

Enter a value to multiply with the top and the bottom elevation (TOP and BOT), e.g MULT=3.0, TOP=TOP*3.0.

Example 1

FUNCTION=CREATEIDF
SOURCEDIR=D:\DATA\TOP*.ASC

The above mentioned example transforms all ESRI ASCII gridfiles that agree with the wildcard TOP*.ASC into the IDF format. The yielding files will have identical names with the extension .IDF, and will be placed in the same folder as their ASCII files, so TOP1.ASC becomes TOP1.IDF.
Files will be overwritten without questioning!

Example 2

FUNCTION=CREATEIDF
SOURCEDIR=D:\DATA\SEL*.ASC
TOPWC=SEL_*.ASC
BOTEL=-0.5

The following example translates all ESRI ASCII gridfiles that agree with the wildcard SEL*.ASC. into SEL*.IDF-files. Moreover, a top elevation (TOPWC) will be extracted from the filename at the position of the wildcard, so the function tries to read a real value at the position of the asterix, suppose the filename is SEL_0.25.ASC, the value finally read is 0.25. It will be used to enter the TOP elevation inside the IDF (see section 9.5 for the syntax of IDF-files). The bottom elevation will be equal to the top elevation (0.25 in this example) plus the given value BOTEL, in this case -0.5, thus bottom elevation is 0.25+-0.5=-0.25.


8.2.9CREATEASC-Function

The CREATEASC function can be used to create ESRI ASC files out of IDF File, see section 9.14. This function will always replace ’****" with a NODATA value.

FUNCTION=

CREATEASC

SOURCEDIR=

Enter the name of a folder that contains a specific set of IDF file(s), e.g. {installfolder}\DATA\RESULTS\HEAD*_L*.IDF. All IDF files that agree will be converted to ASC-files.

Example 1

FUNCTION=CREATEASC
SOURCEDIR=D:\DATA\TOP*.IDF

The above mentioned example transforms all IDF gridfiles that agree with the wildcard TOP*.IDF into the ESRI ASCII format. The yielding files will have identical names with the extension .ASC, and will be placed in the same folder as their IDF files, so TOP1.IDF becomes TOP1.ASC.

Files will be overwritten without questioning!


8.2.10XYZTOIDF-Function

Use this function to create an IDF from a plain data file(s) or IPF file(s) that contain x,y,z data at least. The column (“z”) can contain any type of (real) data. Also use this function to generate a 3D model of the subsoil via indicator-interpolation of various thressholds (lithology and permeability).

FUNCTION=

XYZTOIDF

IDFFILE
(optional)

Enter the name of an IDF-file that need to be created, e.g. IDFFILE=D:\DATA\XYZ.IDF. This keyword is necessary for all entries of GRIDFUNC except GRIDFUNC=VARIOGRAM. Whenever ASSF_IDEPTH=1 or ASSF_IDEPTH=2 (both used for a voxel-interpolation), the output file here specified is used to construct several output files. Suppose IDFFILE=D:\OUTPUT \INT.IDF, the following files will be created:
  • • INT_{THRESHOLD_1}_T{LEVEL}.IDF
    this file describes the probability (0-1) of the occurrence for the lithology specified by the keyword THRESHOLD_1 at LEVEL as specified in ASSF_TOP or INT_L1.IDF. For each THRESHOLD and LEVEL such a file is saved;

  • • INT_T{LEVEL}_L.IDF
    this file describes the main lithology at the level LEVEL;

  • • INT_T{LEVEL}_K.IDF
    this file describes the permeability assigned to the voxel at the level LEVEL;

  • • INT_T{LEVEL}_A.IDF
    this file describes the vertical anisotropy of the voxel at the level LEVEL;

  • • INT_T{LEVEL}_F.IDF
    this file describes the total fraction filled in for the voxel, this should be  1 or otherwise a keyword is missing;

WINDOW=
(optional)

Enter the coordinates of the window that needs to be computed. Enter coordinates of the lower-left corner first and then the coordinates of the upper-right corner, e.g. WINDOW=100000.0, 400000.0, 200000.0, 425000.0. When WINDOW= is absent, the entire XYZFILE or IPFFILE will be gridded for its maximum extent.

CS=
(optional)

Enter the cell size (meter) of the IDFFILE to be created, e.g. CS=100.0. This keyword is not necessary whenever IDFFILE_IN is specified.

NODATA=
(optional)

Enter a NoDataValue for those data points that need to be excluded from the gridding, e.g. NODATA=0.0 to exclude data points equal to zero. By default, NODATA=-999.99.

ILOG=
(optional)

Enter ILOG=1 to perform a log transformation for the data points that need to be gridded. By default, ILOG=0. For ASSF_IDEPTH=4, this parameter is ILOG=1 and cannot be changed to avoid negative thickness.

IDFFILE_IN=
(optional)

Enter the name of an IDF-file for which data points that are equal to its NoDataValue will be interpolated.

MASKIDF=
(optional)

Enter an IDF-file that will be needed to specify what locations will be interpolated, it functions as a mask. It temporarily blanks out the IDF-file given by IDFFILE_IN before the interpolation and resets the original value in the blanked-out area after the interpolation.

XYZFILE=

Enter the name of a plain text file that contains x,y,z data, e.g. XYZFILE=D:\DATA\XYZ.TXT. The format of the file should be: 1st line: header; next lines: x, y, z-data.

IPFFILE=

Enter the name of an IPF file that contains x,y,z data, e.g. IPFFILE=D:\DATA\POINTS.IPF.

IXCOL=
(optional)

Enter the column number of the IPF that contains the x-coordinates, e.g. IXCOL=1 (default value).

IYCOL=
(optional)

Enter the column number of the IPF that contains the y-coordinates, e.g. IYCOL=2 (default value).

IZCOL=
(optional)

Enter the column number of the IPF that contains the z-coordinates, e.g. IZCOL=3 (default value).

IWCOL=
(optional)

Enter the column number in the IPF file name specified at IPFFILE that denotes the column that represents the weighting value for each point in the interpolation, e.g. IWCOL=3. Default IWCOL=0 and no additional weighting is applied. The specified weighting multiplies the internal distance between corresponding points. Higher values for the weighting diminish the influence of points more in the interpolation.

IWFACTOR= (optional)
Enter the procedure to recompute weight values \(w^{\rm ’}\) internally from \(w\) specified by IWCOL. This keyword is optional whenever IWCOL \(>\) 0, the following are distinguished:

  • 1. Specify IWFACTOR=1 to recompute weight values as \(w^{\rm ’}=1.0+(3-\min (3,\log 10(w))\)


The following keywords are only read whenever the IPF file contains associated files and IZCOL is equal to the associated column in the IPF file.

ASSF_
COLUMN=

Enter the column number of the associated file of the given column IZCOL in the IPF, e.g. ASSF_COLUMN=2. In this manner, the gridding will take the values from associated files instead of those from the IPF file. This is only applied whenever the IZCOL is equal to the column in which associated files are listed in the IPF file. For ASSF_IDEPTH=0 and ASSF_IDEPTH=4 this variable is obsolete and by default equal to 1 (the first column is used).

ASSF_
IDEPTH=
(optional)

This parameter prescribes the type of associated and/or how to process it. The following options can be distinguished:

  • 0 This option allows to interpolate time series from the associated files;

  • 1 This option allows to interpolate values from the associated files within spatial constant interfaces, e.g. an upper and lower elevation;

  • 2 This option allows to interpolate values from the associated files within spatial variable interfaces;

  • 3 This option allows to interpolate elevations directly (1\(^{\rm st}\) column) from the associated files;

  • 4 This option allows to interpolate thickness between elevations (1\(^{\rm st}\) column) from the associated files. A thickness for the \(i^{\rm th}\) interval is computed as the difference in elevation between the \(i^{\rm th}\) elevation and the first after that with a value not equal to the nodatavalue of the 1\(^{\rm st}\) column.

Each category obligates a different set of additional optional keywords, described below.


Enter the following items whenever ASSF_IDEPTH=0

ASSF_
STARTDATE=

Enter the starting date from which values are picked from the associated files, e.g. ASSF_STARTDATE=20121231.

ASSF_
ENDDATE=

Enter the end date to which values are picked from the associated files, e.g. ASSF_ENDDATE=20160515.

ASSF_DDATE=

Enter the time interval for which subsequent gridding is carried out, e.g. ASSF_DDATE=14 which mean that each 14 days between the given ASSF_STARTDATE and ASSF_ENDDATE will be processed. Alternatively the following keywords can be applied:

  • D Daily;

  • W Weekly;

  • M Monthly;

  • Y Yearly;

  • T Twice a month, 14\(^{\rm th}\) and 28\(^{\rm th}\).


Enter the following items whenever ASSF_IDEPTH=1

ASSF_
TOP=

Enter the uppermost elevation of the first interface, e.g. ASSF_TOP=4.0.

ASSF_
BOT=

Enter the lowermost elevation of the last interface, e.g. ASSF_BOT=-40.0.

ASSF_
DZ(.)=

Enter the thickness of all interfaces, e.g. ASSF_DZ=5.0. This can be a list of values as well, e.g. ASSF_DZ=5.0,2.5,10.0. In this case the first interface has a thickness of 5.0 m, the second 2.5 m and the third 10.0 m, all the other remaining interfaces will have 10.0 m as well.

ASSF_
ZPLUS=

Enter the vertical offset to be applied to look beyond the current interface, e.g. ASSF_ZPLUS=0.5. In this case, the boreholes will be read for a length of DZ(\(i\)) \(\pm \) ASSF_ZPLUS.


Enter the following items whenever ASSF_IDEPTH=2

NLAY=

Enter the number of interfaces, e.g. NLAY=10. The interpolation of information will take place in between the interface \(i\) and \(i+1\).

INT_L{i}=

Enter the IDF file for each interface \(i\) up to NLAY, e.g. INT_L1=D:\DATA\INTERFACE_L1.IDF.


Enter the following items whenever ASSF_IDEPTH=3 or ASSF_IDEPTH=4

NLAY=

Enter the number of interfaces, e.g. NLAY=10. The interpolation of intervals will take place for interval 1 up to 10. If NLAY=-10, only the 10\(^{\rm th}\) interval is computed.


Enter the following items whenever ASSF_IDEPTH=1 or ASSF_IDEPTH=2

KSUM=
(optional)

Enter KSUM=1 to generate permeability value as a weighted sum of all individual permeability value within each vertical interval. By default KSUM=0 and the permeability is that permeability associated with the most common lithology.

TRIMTOP_IDF=
(optional)

Enter the name of an IDF file to be used to trim the interpolated values at the top, e.g. TRIMTOP_IDF=D:\DATA\DEM.IDF.

TRIMBOT_IDF=
(optional)

Enter the name of an IDF file to be used to trim the interpolated values at the bottom, e.g. TRIMBOT_IDF=D:\DATA\BEDROCK.IDF.

TRIMCONF_IDF=
(optional)

Enter how TRIMTOP_IDF and/or TRIMBOT_IDF need to be treated. If TRIMCONF_IDF=1 (default), the trimmed area blocks a point whenever this area need to be crossed over, to reach the point. If TRIMCONF_IDF=0, the blocked area does not have an influence on the interpolation and will be used solely to convert portion into Nodata that are discarded due to the values of TRIMTOP_IDF and/or TRIMBOT_IDF.

INDICATOR=
(optional)

Enter INDICATOR=1 (by default INDICATOR=0) to use an indicator interpolation. Whenever this function is used, a value is assigned to a point whenever it meets a given threshold (see NTHRESHOLD). In that case it gets score of 1.0, this is corrected for the penetration length of this in the current interval. After interpolation it yields a probability of occurrence, a fraction between 0.0 and 1.0. Use INDICATOR=-1 to skip the interpolation and recompute the probability of occurrence and permeability from the existing files, in case INDICATOR=1 is applied first.

NTHRESHOLD=

Enter the number of thresholds to be used in the indicator interpolation, e.g. NTHRESHOLD=2.

THRESHOLD{i}=
Enter for each threshold the appropriate name, e.g. THRESHOLD1=SAND. Use quotation marks for thresholds with spaces, e.g. THRESHOLD{i}=“SILTY SAND”. Enter NTHRESHOLD number of thresholds. iMOD will generate a probability map for each threshold for each interval. It also generates a map per interface of the most-common threshold per grid cell.

KH_THRESHOLD{i}=
Enter for each threshold the horizontal permeability, e.g. KH_THRESHOLD1=35.0. Enter NTHRESHOLD number of horizontal permeability values. iMOD will generate a horizontal permeability map for each threshold for each interval. It also generates a total, averaged horizontal permeability map per interface as the weighted sum of all individual thresholds.

KV_THRESHOLD{i}=
Enter for each threshold the vertical permeability, e.g. KV_THRESHOLD1=10.0. Enter NTHRESHOLD number of vertical permeability values. iMOD will generate a vertical permeability map for each threshold for each interval. It also generates a total, averaged vertical permeability map per interface as the weighted sum of all individual thresholds.

GENFILE=
(optional)

Enter the name of a Gen-file that contains the data x,y,z data, e.g. GENFILE=D:\DATA\DATA.GEN.

IZCOL=
(optional)

Enter the column number in the GEN file that contains the z-coordinates, e.g. IZCOL=3 (default value).

SOURCEDIR=
(optional)

Enter the folder and wildcard that corresponds to the source files, e.g. D:\DATA\REGION*.XYZ, REGION*.IPF. Keywords that denote the source of the files, such as XYZFILE, IPFFILE, IDFFILE_IN, GENFILE are obsolete in that case.

TARGETDIR=
(optional)

Enter the folder to which the IDFFILEs will be saved that correspond to the XYZFILEs or IPFFILEs found in the SOURCEDIR, e.g. TARGETDIR=D:\DATA\IDFS, the results will be called D:\DATA\IDFS\REGION*.IDF whenever SOURCEDIR=D:\DATA\REGION*.XYZ. This keyword is compulsory whenever the optional keyword SOURCEDIR is applied.

GRIDFUNC=

Enter the grid function to be used:

MIN

Computes the minimum of all data points inside a grid cell;

MAX

Computes the maximum of all data points inside a grid cell;

MEAN

Computes the mean of all data points inside a grid cell;

PERC

Computes the percentile of all data points inside a grid cell.

PERCENTILE=
Enter the percentile (\(>\)=0 PERCENTILE \(<\)=100.0) whenever GRIDFUNC=PERC, e.g. PERCENTILE=25.0. A percentile value will be interpolated linearly, whenever the entered PERCENTILE falls in-between two values. Entering PERCENTILE=0.0 or PERCENTILE=100.0 will yield the same results as with GRIDFUNC=MIN and GRIDFUNC=MAX, respectively, however, the latter functions are faster than the function GRIDFUNC=PERC. Entered values beyond 0.0 and above 100.0, will be trimmed to 0.0 and 100.0, automatically.

BIVAR

takes a bivariate interpolation

SKRIGING
OKRIGING

takes a Kriging interpolation, SKRIGING stands for Simple Kriging (assuming a constant mean over the entire domain); OKRIGING stands for Ordinary Kriging (assuming a constant mean in the neighborhood of each estimation point). Choose one of both at one time.

COINCIDENT= (optional)
Enter the minimal distance of points to coincide. By default COINCIDENT=0.1 \(\times \) CS.

RANGE(.)=
Enter the range that defines a neighbourhood within which all data points are related to one another, e.g. RANGE=1000 meter. It is possible to specify multiply values for RANGE whenever ASSF_IDEPTH=2 for each interface, e.g RANGE=1000.0,500.0,7500. If the number of entered values for RANGE is less than the number of interfaces (NLAY) to be computed, the last entered values for RANGE will be re-used for the remaining interfaces. The semivariance will become approximately equal to the variance of the whole surface itself (SILL).

SILL=
Enter the distance at which the semivariance approaches a flat region. SILL is referred as the range or span of the regionalized variable, e.g. SILL=2500. This parameter resemblances a variance. The magnitude of the semivariance between points depends on the distance between the points. A smaller distance yields a smaller semivariance and a larger distance results in a larger semivariance.

NUGGET=
Enter the offset of the semivariogram, e.g. NUGGET= 10.0.

KTYPE=
Enter the type of the Kriging model to be used to compute the value at X\({}_{i}\), choose from:

  • 1. Linear Model
    X\({}_{i}\)=DIST\({}_{i}\)*(SILL-NUGGET)/RANGE

  • 2. Spherical Model
    DIST\({}_{i}\)\(<\)=RANGE:
    X\({}_{i}\)=SILL*(1.5*(DIST\({}_{i}\)/RANGE))-(0.5*(DIST\({}^{3}\)/RANGE\({}^{3}\)))
    DIST\({}_{i}\)\(>\)RANGE:
    X\({}_{i}\)=SILL

  • 3. Exponential Model
    X\({}_{i}\)=SILL*(1.0-EXP(-DIST\({}^{3}\)\({}_{i}\)/RANGE))

STDEVIDF=
Enter the name for the standard deviation computed. The output file here specified is used to construct several output files. The names of the output files are created using both the keyword IDFFILE and keyword STDEVIDF. Suppose STDEVIDF=D:\OUTPUT\VAR.IDF and IDFFILE=D:\OUTPUT\INT.IDF, the following files will be created: INT_VAR_{THRESHOLD_1}_T{LEVEL}.IDF.

PNTSEARCH= (optional)
Specify PNTSEARCH=1 to allow to search for points within the distance specified by RANGE the minimum number of points used for the interpolation. Default MINP=10 (or less whenever the dataset contains less points).


Enter the following optional keywords only whenever PNTSEARCH=1.

IQUADRANT= (optional)
Select IQUADRANT=1 to force an equal distribution of point from the four quadrants around an point to be estimated. This keyword can be entered only whenever PNTSEARCH=1. By default IQUADRANT=0.

MAXPNT= (optional)
Enter the maximal number of interpolation points needed for the interpolation, e.g. whenever MAXPNT=50, iMOD will take maximal 50 nearest points in the Kriging interpolation. Whenever the keyword IQUADRANT=1, the entered MAXPNT value is valid for each quadrant, so whenever MAXPNT=10 and IQUADRANT=1, the total number of points will be maximal MAXPNT=10 \(\times \) 4 = 40. Default value is MAXPNT=0 which means that all points are used that agree the constraints.


Enter the following optional keywords only whenever PNTSEARCH=1 and IQUADRANT=0.

ZONE_IDF= (optional)
Specify an IDF file with zones that force the Kriging interpolation to take point into the computation that are within a similar zone, e.g. ZONE_IDF=D:\ZONES.IDF. This is equivalent to the NBLNFILE option which acts from GEN files instead. Note A cell with NodataValue discards an interpolation at that location.

ELLIPS_ANGLE1 / ELLIPS_ANGLE2 / ELLIPS_ANGLE3=
Angles along the three-major axes of the Euclidean coordinate system.

ELLIPS_RANGE1 / ELLIPS_RANGE2 / ELLIPS_RANGE3=
Range (meters) of the ellipse along the three-major axes of the Euclidean coordinate system.

ELLIPS_LEN= (obsolete from v5.2)

ELLIPS_ANI= (obsolete from v5.2)

ELLIPS_RAT= (obsolete from v5.2)

VARIOGRAM

Creates a semivariogram, this yields no interpolation of the data, it generates a table filled in with a variogram. Whenever the WINDOW keyword is specified, a variogram will be computed for those data points that are within the bounds of the given WINDOW. The results will be written in the VARIOGRAM.TXT file, see coming pages for an example.

LAG-INTERVAL=
Enter the number of distances over which the VARIOGRAM will be computed, e.g. LAGINTERVAL=50 will yield fifty intervals equally distributed between zero and the maximum distance between point.

LAG-DISTANCE=
Specify the lag distance, e.g. LAGDISTANCE=50.0 to overrule the lag distance as computed by LAGINTERVAL.

PCG

takes a Preconditioned Conjugate Gradient interpolation

HCLOSE= (optional)
Enter a closure criterion for the PCG solver to terminate the interpolation, e.g. HCLOSE=0.001 (this is the default).

RCLOSE= (optional)
Enter a closure criterion for the PCG solver to terminate the interpolation, e.g. RCLOSE=1000.0 (this is the default).

NINNER= (optional)
Enter the number of inner iteration for the PCG solver, e.g. NINNER=50 (this is the default). Use large values for NINNER to speed up the interpolation since the problem to be solved is linear.

NBLNFILE=
(optional)

Specify the number of GEN-files that need to be taken into account in the grid-interpolation.

BLNFILE_{i}=

Give the name of a specific GEN-file containing x,y-data of the faults that need to be taken into account in the grid-interpolation. Repeat this keyword for NBLNFILE times.

FCTBLNFILE_{i}=
(optional)

Enter the multiplication factor for each BLNFILE for which the points will be moved further away if they are on both sides of a fault cq. line in the GEN file. Repeat this keyword for NBLNFILE times.

IBLNTYPE=
(optional)

Specify the type of BLNFILE which denotes how iMOD will use the BLNFILE.
  • IBLNTYPE=0 (default)
    In this configuration iMOD treats the entries in the GEN file as break line. Points that can be “seen” without intersecting a line from the GEN will be applied in the corresponding interpolation.

  • IBLNTYPE=1
    In this configuration iMOD treats the entries in the GEN file as polygons. Points within the same polygon will be used in the corresponding interpolation.

Example 1

FUNCTION=XYZTOIDF
XYZFILE=D:\DATA\28BN.XYZ
IDFFILE=D:\DATA\28BN.IDF
CS=5.0
GRIDFUNC=MEAN

Above an example is given how to rasterize, for a 5x5 resolution (CS=5.0), the content of an XYZ file by means of its mean values (GRIDFUNC=MEAN) inside the individual rastercells. The default NoDataValue of -999.99 will be assigned to those rastercells that doesn’t have any points inside, moreover, data points that have this particular value will be left out.

Example 2

FUNCTION=XYZTOIDF
SOURCEDIR=D:\DATA\*.XYZ
TARGETDIR=D:\DATA\IDF
IDFFILE=D:\DATA\28BN.IDF
CS=25.0
GRIDFUNC=PERC
PERCENTILE=5.0
NODATA=0.0

Example above shows how to rasterize, for a 25x25 resolution (CS=25.0), the content of all *.XYZ files in the folder D:\DATA, by means of its 5.0 percentile values (PERCENTILE=5.0; GRIDFUNC=PERC) inside the individual rastercells. A NoDataValue of 0.0 will be assigned to those rastercells that doesn’t have any points inside, moreover, data points that have this particular value will be left out.

Example of Bivariant interpolation:

pictures/h6-h71/image927.png

Example of PCG interpolation:

pictures/h6-h71/image928.png

Example of MEAN sampling:

pictures/h6-h71/image929.png

Example of Kriging interpolation (linear model):

pictures/h6-h71/image930.png

Example of a Variogram:

pictures/h6-h71/image931.png

From the above presented variogram, the SILL would be 30 and the corresponding RANGE approximately 1000m, at that distance the SILL value flattens. The NUGGET is zero in this example.

Example of the different models to be used in the Kriging interpolation:

pictures/h6-h71/image932.png