iMOD User Manual version 4.4 (html)

11.1Tutorial 1: Map Display

This tutorial gives a brief introduction to several display options for IDF (rasters) and IPF (points) files. See for more detailed references Chapter 6 and subsections.


This is what you will do:

Required Data

For this tutorial you need the following files: Airphoto bitmap, shapefile (GEN), iMOD Data Files (IDF), iMOD Point Files (IPF) and TXT-files to which the IPF-files are directing:

All these files are located in the folder:{installfolder} \TUTORIALS \TUT_MAP_DISPLAY.

Note: {installfolder} refers to the full path of the directory you installed iMOD in (e.g. D:\iMOD). Note: If you are a left-handed person and you converted your mouse button settings, ’left mouse button’ should be ’right mouse button’ and vice versa in these tutorials.

Getting Started

The IMOD_INIT.PRF is the only file that iMOD needs at the initial startup. If it does not exist, iMOD will create one. The file contains several keywords that are needed by a variety of functionalities in iMOD, however, the keyword USER is the only one that is obligatory. In the coming up tutorial you’ll notice that the content of the IMOD_INIT.PRF file will change. Let us examine the current content.

This displays the Preferences window. On default the keyword [USER] is selected and the path that is assigned to that keyword is displayed underneath the list box. Probably it shows the folder{installfolder} \IMOD_USER. Several folders will be created in the USER folder. Those folders might be used by iMOD for different purposes, moreover, during your iMOD sessions new folders could be created. However, the most important thing you need to remember about the USER folder is that it stores data created by iMOD, e.g. temporary files, model results and drawings. In this case you might interpret a USER folder as a project folder as well, e.g. USER D: \IMOD \PROJECT_X.

Okay, let us continue with iMOD.

An empty graphical window will appear with default axes and a scale bar. The initial position of the graphical window is (-10,-10) by (10,10). It is possible to turn off the axes and scale bar, so:

Show a background images and shapes One of the first things one would like to display is an image of the underlying topography. Let’s do that.


Figure 11.1: Example of showing a topographical map.

Besides displaying underlying topography more often background Shape files (polygons or lines) are available. You can think of administrative boundaries (country, state, city) or geohydrological boundaries (rivers, polders, drainage system). iMOD uses the GEN files format for storing shape file information (more on the GEN format in Section 9.11). Let’s add a background GEN file.


Figure 11.2: Example of imported and coloured GEN file as Overlay.

Display of an IDF-file

An IDF-file stores rasterized data, let us open an IDF-file:

Observe that the loaded IDF-file emerges in the iMOD Manager. iMOD will not adjust the zoom level automatically to display the entire IDF.

Note: Please remember that a right-click of the mouse button is necessary to stop moving the map around (  pictures/h6-h71/image946.png ).


Figure 11.3: Example of a 2D IDF-view.

Adjust the legend

Each IDF-file that has been loaded into the iMOD Manager will be displayed by a legend with values that decline linearly between the maximum and minimum values of the IDF-file. A legend is connected to the IDF internally and can be changed easily.

By selecting the percentile option, iMOD will compute classes for a legend based on the distribution of the IDF values, like a duration curve. Since the option Current Zoom Level has been chosen, the legend will be computed for those values that are inside the current zoom level only.

Adjusting a legend like this automatically, is extremely useful whenever the content of an IDF-file needs to be explored. However, legends can be constructed manually and/or loaded from disk.

In this way it is easy to change the colour range of the legend.


Figure 11.4: Example of a two-coloured legend.

Let’s use more colours in the legend.

iMOD distinguishes two types of legends:

Reopen the Legend window (step Item 30.) again and let us create a legend with 10 classes:

Let’s look at another way of adjusting the legend, more convenient actually.

iMOD will try to adjust the number of classes such that a legend is created with nicely legend classes, automatically. Select the Take classes as-is option whenever you do not want iMOD to create nice, round classes. Or, alternatively when you do want to have more control on the legends, select the option Fixed Interval and specify the interval, minimal and maximal values for the legend classes.

Let us plot a legend on the map

Select the canvas window with your left-mouse button and observe how the cursor changes when the mouse is moved to the boundary of the legend, this grey rectangle is the “legend-box”.

The text size of the legend will be adjusted automatically to fit the boundary box of the legend. Change the width or height of the legend box in case the label text is not readable.

Let us open some more IDF-files.

Whenever more than one IDF-file is selected in the iMOD Manager the Legend button will become inactive. However, the following method can be used to adjust all legends simultaneously.


Figure 11.5: Example of the ’Synchronize legend by:’ window.

Some of the IDF files show white spots as the current legend does not cover all IDF files properly. You can change a legend also to match all selected IDF files.

All IDF files will have a similar legend but the legend classes cover the content of all selected IDF filis.

Display of an IPF file

An IPF file stores pointwise information, such as boreholes and/or observation wells. Let us open such a file.

An IPF file is an iMOD-Point-File and see Section 9.7 for more detailed information about the content of these IPF files. The IPF file that we’ve just opened in iMOD does contain the following information:

Be aware of the fact that all of these attributes do not have any direct meaning in iMOD or whatsoever. In the next steps we will show how these attributes can be used in iMOD.

All points will be plotted as grey dots initially, however, it is easy to change that.

iMOD will use the first column of the IPF file (label is X-CRD) for the X coordinate (X-Coordinate:) and the second column (label is Y-CRD) for the Y coordinate (Y-Coordinate:). On default, the Z coordinate will be assigned to the first column, too, which is incorrect.

iMOD is able to position points in 3D and/or in cross-sections when this Z-Coordinate: is assigned properly.

iMOD will increase the symbol to scale each point linearly for values for the chosen label [I_USED]. This feature can be useful to emphasize specific points on a map. The method can varied, we leave it now at [True Value], see Section 6.8 for more information on this.

All points will be coloured as cyan (light-blue) in this manner, however, a legend can be used to colour the points as well, so:

iMOD will create a legend initially, based on the minimum and maximum values of the label [Z_END]. The legend functionalities as described by step Item 30.-Item 39. can be applied to IPF files too.

iMOD colours all points by their values for the label [Z_END] and scale all for values of [I_USED]. Values that are 0.0 got a size of 1.0 and those that are 1.0 got a size of 5.0. If any other values are in between, those will be scaled linear in between.


Figure 11.6: Example of display of points with different scaled markers.

Let us adjust the zoom level such that we enter coordinates that are the centre of the current zoom level.

As we used Zoom (m) as [500.0], the zoom level will have a minimum width and/or height of about 2 x 500 meter. Let us measure that.

The Measurement tool can be used to identify distances between objects on the map, use the left mouse button to include more points during the measuring of the distance.

Since we’ve zoomed in, let us place some labels to the points to see the actual values for [Z_END].

Notice that some labels will overlap other labels. iMOD does not support (yet) any advanced labelling to avoid overlapping. Use the zoom functionalities to avoid overlapping.


Figure 11.7: Example of plotted labels using the ’Labels’ button of the IPF Configure window.

Let’s turn off all labeling again and examine our data set in 3-D.

By default the colouring used to display the boreholes is different than used in this dataset, so we will load the proper legend file used for displaying the lithology of the boreholes.

iMOD will reload the IPF file and displays the boreholes according to the legend read from the DLF file. See Section 9.18 for more detailed information about a DLF file.

The 3D Tool is simulated by OpenGL libraries and is very powerful; however, the display of borehole data can take a while to load since all boreholes are stored in individual text files that need to be processed sequentially. The associated IO consumes most of the time.


Figure 11.8: Example of a 3D-display of boreholes.

Let us reshape the representation of the boreholes. As you can notice each borehole represents a lithology as displayed in the Legend for Boreholes table. This legend can be created inside and/or outside iMOD; however, the last column expresses the width that will be used to present the corresponding lithology. So, [Clay] is displayed by a smaller width (with=0.25) than [Sand] that has a width of 1.0.


Figure 11.9: Example of using different thickness’s when displaying lithology of boreholes in 3D.

Alternatively we can change the 3D representation of the borehole.

Often the number of boreholes is large and therefore we would like to concentrate on those with a particular bore depth. Let us select only those with a penetration depth of more than 30 meter.

The Point Information tab gives an overview of the basic point characteristics of the selected borehole. The Borehole Information tab displays the specific drill information (including Lithology and sand-fraction) for each individual layer. Repeat this procedure for different boreholes by selecting the Map Value button again.

Let us combine in 3D the boreholes with the top and bottom IDF’s we’ve loaded into iMOD previously.

You’ll notice that prior to the 3D tool the 3D IDF Settings dialog appears. In this dialog the appearance of the IDF-files can be configured. For example, an IDF can be represented by planes (quads between mids of gridcells giving a smooth surface) and/or cubes (representing the gridcells as flat surfaces, like Lego-blocks). However, any adjustments in this dialog can be made while in the 3D environment as well, so let us accept the dialog as it is.


Figure 11.10: Example of 3D image of a set of planes and boreholes; display depends on options chosen in the 3D IDF Settings-window.

You’ll see the graphical representation of the surface for the different IDF’s. Another way to do that is by means of a cross-section (Section 11.3). Since the IDF-files represent a clay-body, it is nice to draw them as solids.

Each row defines how that particular IDF will be displayed. To make a solid of two IDF-files you should combine an IDF with another one. The next image shows how the settings should be configured. For example we combined the IDF-file Formation-KR_TOP.IDF (top of the KR-formation) with Formation-KR_BOT.IDF (bottom of the KR-formation) by selecting that file from the dropbox in the third column. Also we changed to Off the Type in the second column of the Formation-KR_BOT.IDF-file. Similarly we adjusted this for the NAWO formation.


Figure 11.11: Example of a 3D IDF Settings window for displaying pairs of IDF’s as solids.


Figure 11.12: Example of 3D-image of displaying pairs of IDF’s as solids.

Another thing that can be done in 3-D is to create our own set of boreholes. This be especially helpful for getting familiar with the geology at a particular spot. Let’s make some “artificial” boreholes.

It is not necessary to deselect existing IPF files before adding artificial boreholes, however for reasons of illustration it is more clear to turn them off for now.

The following window appears in which you can specify how those artificial wells need to be defined. We will create them manually.


Figure 11.13: Example of the Create An Artificial Well window.


Figure 11.14: Creating artificial well on the 3-D graphical canvas interactively.

iMOD will generate a set of boreholes in the commonly known IPF file structure (see Section 9.7) and they will be added to the IPFs tab on the 3-D Tool window.

You can see the create boreholes through the geology. iMOD add a colour legend to the boreholes automatically. Pretty nice, isn’t it?


Figure 11.15: Results of the artificial wells.

Okay let’s do something else now.

Let us open another IPF file.

All observation points are displayed by a grey circular dot, however, these points have timeseries associated. Let us look at these associated timeseries.

By default any “ \” string will be deleted from the ID field, so the ID-string will shorten whenever it will be displayed on the graphical canvas.

Observe the results. You might want to change the number of labels by repeating steps Item 116. to Item 118. again.


Figure 11.16: Pop-up window with ’Select For’ option when right-clicking on canvas when IPF Analyse window is active.

iMOD finds any point that satisfies this search string. Notice that the wildcard is necessary at the first portion of the search string, since all label IDs start with “observation \”. As a result 6 points will be selected and displayed in the table on the IPF Analyse window. Let us display the associated time series.

Two windows are displayed; Table of Associated Files Content and IPF Analyse Figure. Whenever one time series is selected in the Select one/more to plot list, a table is presented with the actual values for the time series on the Table of Associated Files Content window, let’s do that


Figure 11.17: Example of plotted as figure and table using the button ’IPF Figure’ from the window IPF Analyse.

Let us look at another way of adding/deleting points from the selection table.

Additionally to the display options of timeseries in the IPF Analyse Figure window, let us plot timeseries on the map.


Figure 11.18: Example of plotted timeseries next to selected points using the option ’Simple’ from the Graph dropdown menu in the Setting tab of IPF Analyse.

For those points in the selection table on the Attributes tab, their associated timeseries will be plotted on the map. Each time another point is added or deleted the display is updated.

Whenever a small crossed-out rectangle is displayed, it means that the associated timeseries for that point is missing.

Whenever the IPF Analyse window is closed, timeseries cannot be plotted on the map anymore.

Save /Open a Display Configuration

The entire configuration of legends and settings for the files that are loaded in the iMOD Manager can be saved on disk. Whenever iMOD will be restarted, this file can be loaded to recover the iMOD session again.

The filename entered will be saved in the {USER} \IMFILES folder on default, however, another location can be entered too. For reasons of efficiency and transferability, it is advisable to store these IMF files in that particular folder.

Let us quit iMOD now.

Let us restart iMOD.

As expected, the original iMOD session has been restored.