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iMOD User Manual version 5.2 (html)


8.9IPEST-FUNCTIONS


8.9.1CREATEPILOTPOINTS-Function

Use this function to generate a set of pilot points for iPEST, these can be used during an iPEST optimization. The function uses the geohydrology of the model to group pilot points in between different model layers.

FUNCTION=

CREATEPILOTPOINTS

IPF=
(optional)

Specify IPF=1 to use a Delauney Triangulation to compute the optimal distribution of Pilot Points. A Delauney Triangulation performs a triangulation of point for which each circumcircle of each triangle does not contain any other points that the points of the corresponding triangle. By default IPF=0.


Specify the following keyword whenever IPF=1

IPFOBS=

Specify the IPF file to be used to compute the triangulation, e.g. IPFOBS=D:\OBS\OBS_GWF.IPF.

IPFMES=
(optional)

Specify the IPF file to be used to remove points that are within the points from this speicified IPF file, e.g. IPFMES=D:\MES\MEASURE.IPF.

IPFPPS=

Specify the IPF file to be used to compute the triangulation, e.g. IPFPPS=D:\PPOINTS\PILOT_POINTS.IPF.

IDF=
(optional)

Specify an IDF file for which its NodataValue is used to exclude points from the IPFOBS, e.g. IDF=D:\THICKNESS\THK_L1.IDF.

DCLUSTER=
(optional)

Specify the distance for which points from the IPF file specified at IPFOBS are clustered before the triangulation, e.g. DCLUSTER=1000 meter. Points here within a distance of 1000 meter are clustered at the midpoint of the selected points within the cluster.

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 minimal and maximal values for the rectangle for the entered IPFOBS are used to determine the extent of the triangulation.

NBORDER=
(optional)

Specify the number of points along the borders of the rectangle used for the triangulation, e.g. NBORDER=2. The higher NBORDER, the more detail of the triangulation appears along the border. By default NBORDER=1and need to be at least 1. If NBORDER=2 a point is positioned in the mid of each side of the rectangle.

PPTYPE=
(optional)

Specify the type of distribution for the pilotpoints, select from the following:

  • • 0 Select this value to position the pilot points at the original (and clustered) points;

  • • 1 Select this value to position the pilot points at the Delauney location (circumcenter) points. As a consequence, those points might be outside the corresponding triangle and/or close to others as the figure below displays. Using this type is not recommended though;

  • • 2 Select this value to position the pilot points at the incenter points of each triangle;

  • • 3 Select this value to position the pilot points at the midpoints of each triangle, this option is the default value and mostly recommended.


Delauney triangulation and the layout of pilotpoints for different values of PPTYPE.


pictures/Ch-imod-batch/pilotpoints.png

ILAYER=
(optional)

Specify the layer number to be used in the PRJ file. By default ILAYER=1.

IGROUP=
(optional)

Specify the layer number to be used in the PRJ file. By default IGROUP=1.

PTYPE=
(optional)

Specify the parameter type (see section 10.19) to be used in the PRJ file. By default PTYPE=KH.


Specify the following keyword whenever IPF=0

DX=

Specify the distance in between pilot points in meters, e.g. DX=100.0.

NLAY=

Specify the number of model layers, e.g. NLAY=10.

BND_L{i}=

Specify an IDF with the active areas of the model for the \(i^{\rm th}\) model layer, e.g. BND_L5=d:\DATA\BND.IDF. Values of \(\le 0.0\) are discarded. Repeat this keyword for NLAY times. It is also possible to specify a constant value as e.g. BND_L5=1.

IQ3D=
(optional)

Select whether the model is QUASI-3D (IQ3D=1) or 3D (IQ3D=0). By default IQ3D=1 and a quasi 3D model is assumed.

IAQUIFER=
(optional)

Select whether the Pilot Points need to be defined for an aquifer, define IAQUIFER=1 in that case, by default IAQUIFER=0. In case IQ3D=0, IAQUIFER=1 and this cannot be modified.

IAQUITARD=
(optional)

Select whether the Pilot Points need to be defined for an aquifer, define IAQUITARD=1 in that case, by default IAQUITARD=0. In case IQ3D=0, IAQUIFER=0 and this cannot be modified.

IVCW=
(optional)

Specify IVCW=1 to generate pilot points for the parameters KD (if IAQUIFER=1) or for VC (if IAQUITARD=1). By default IVCW=0 and parameters KH (if IAQUIFER=1) or for KV (if IAQUITARD=1) are created.

VCW_L{i}=

Specify an IDF for the vertical resistance in between model layer \(i\) and \(+1\), e.g. VCW_L5=d:\DATA\VCW_L5.IDF. Repeat this keyword for NLAY-1 times. This keyword is only necessary in case IVCW=1. It is also possible to specify a constant value as e.g. VCW_L5=100.

TOP_L{i}=

Specify an IDF for the upper elevation of model layer \(i\), e.g. TOP_L7=d:\DATA\TOP_L7.IDF. Repeat this keyword for NLAY times. This keyword is only necessary in case IVCW=0. It is also possible to specify a constant value as e.g. TOP_L7=-23.032.

BOT_L{i}=

Specify an IDF for the lower elevation of model layer \(i\), e.g. BOT_L7=d:\DATA\BOT_L7.IDF. Repeat this keyword for NLAY times. This keyword is only necessary in case IVCW=0. It is also possible to specify a constant value as BOT_L7==120.32.

KVV_L{i}=

Specify an IDF for the vertical permeability in between model layer \(i\) and \(+1\), e.g. KVV_L5=d:\DATA\KVV_L5.IDF. Repeat this keyword for NLAY-1 times. This keyword is only necessary in case IVCW=0. It is also possible to specify a constant value as KVV_L5=0.01.

KHV_L{i}=

Specify an IDF for the horizontal permeability for model layer \(i\), e.g. KHV_L5=d:\DATA\KHV_L5.IDF. Repeat this keyword for NLAY times. This keyword is only necessary in case IQ3D=0. It is also possible to specify a constant value as KHV_L5=25.0.

KVA_L{i}=

Specify an IDF for the vertical anisotropy for model layer \(i\), e.g. KVA_L5=d:\DATA\KVA_L5.IDF. Repeat this keyword for NLAY times. This keyword is only necessary in case IQ3D=0. It is also possible to specify a constant value as KVA_L5=0.3.

MINC=
(optional)

Specify the minimal vertical resistance in order to assign a (new) pilot point at that location, e.g. MINC=100 to specify that the resistance need to be minimal 100 days in order to assign a (new) pilot point. If not, a pilot point for that location is created but it belongs the same group as the pilot point in the previous model layer.

MASK=

Specify the name of a mask file, e.g. MASK=d:\MASK.IDF. Values in the MASK file that are equal to zero or its NodataValue will be inactivated in the PilotPoints. During an optimization, those remain 1.0.

OUTPUTFOLDER=

Specify the name of the output folder. Here the IPF files (PILOTPOINT_{PARAMETER}_L{LAYER}.IPF) and the PILOTPOINT.PRJ file will be saved. The IPF files contains the values from the TOP_L- and BOT_L-files as well. The can be inspected in the iMOD 3-D Tool. IN the case IVCW=1, the TOP and BOT values are the negative model layers. The PRJ file describes the section within the PST section in a PRJ file. It lists all the parameters and IPF files. The header of the file need to be modified before submitting it into a complete PRJ file, e.g. OUTPUTFOLDER=d:\IPESTOUT.

Example

FUNCTION=CREATEPILOTPOINTS
IAQUIFER=1
IVCW=1
MINC=50.0
DX=1500.0
NLAY=2
BND_L1=D:\DATA\BND_L1.IDF
BND_L2=1
VCW_L1=D:\DATA\VCW_L1.IDF
OUTPUTFOLDER=D:\OUTIPEST


8.9.2CREATEIZONE-Function

Use this function to calculate zones and corresponding fractions per model layer based on geologic formations, these IDF files can be used during an iPEST optimization.

FUNCTION=

CREATEIZONE

OFOLDER=

Give an output folder name to store all the zones per model layer, e.g. OFOLDER=D:\iPEST \IPEST_FRACTIONS. iMOD creates next to these zone-IDF files, two files PARAM.TXT and ZONES.TXT. The first can be used to insert in a RUN- and/or PRJ file in the parameter section, the other can be added to the zone-section.

PFOLDER=

Give a folder name that contains the fraction per model layers per geological formations, e.g. PFOLDER=D:\iPEST \GEO_FRACTIONS; there are the result of the function IPFSPOTIFY, see section section 8.5.2.

NLAY=

Enter the number of model layers, e.g. NLAY=6. These need to be at least equal to the number of model layers used in the IPFSPOTIFY function, see section section 8.5.2.

MINF=

Minimum fraction to assign a parameter to a zone, e.g. MINF=0.05 which mean a fraction of 0.05 (5%) which a fraction need to be before it adds to a zone.

IZONEOFFSET=

Enter the offset number of zones, e.g. IZONEOFFSET=0, which means that the numbering of zones start at 0, and the first will be 1.

IGROUPOFFSET=

Enter the offset number of groups, e.g. IGROUPOFFSET=10, which means that the number of groups starts at 10 and the first new group is 11.

NFORMATIONS=

Enter the number of formations, these need to be the number of formations found from the IPFSPOTIFY function, see section section 8.5.2.

FORMATION{i}=

Enter the IDF file name for the i\({}^{th}\) formation, e.g. FORMATION1=HLC.IDF iMOD will look for fraction grids with this name within each folder (PFOLDER) for the entered number of model layers.

TPARAMETER=

Enter the name of the parameter to be optimized, e.g. TPARAMETER=KH. Any of the iPEST parameters can be defined from section section 10.19.

Example

FUNCTION=CREATEIZONE
OFOLDER=D:\IPEST_FRACTIONS
PFOLDER=D:\GEOLOGY_FRACTIONS
NLAY=2
MINF=0.05
IZONEOFFSET=0
IGROUPOFFSET=0
NFORMATIONS=2
FORMATION1=HLC.IDF
FORMATION2=BEZ1.IDF
TPARAMETER=KH

The example above will generate the PARAM.TXT and ZONES.TXT that can be inserted in an existing RUN- and/or PRJ-file for iPEST. Besides, it creates per model layer the zones (including the fractions) per formation.