iMOD User Manual version 4.4 (html)

11.3Tutorial 3: Map Analyse

This tutorial gives a brief introduction to several options to visualize and analyse the content of IDF (raster) files. See for more detailed references Section 7.1 (Cross-Section Tool), Section 7.2 (Timeseries Tool) and Section 7.3 (3D Tool).


This is what you will do:

Required Data

For this tutorial you need the following iMOD Data Files (IDF):

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

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


Let us start by creating a cross-section that visualizes the subsoil system as described by the data stored in the folder SUBSOILSYSTEM.

All files will appear in the iMOD Manager, they will be ordered similar to the order in which they appeared in the Windows Open File window. Whenever the Cross-Section Tool is used to visualize the subsoil system it is important that IDF-files are arranged such that internal values are higher for IDF-files that appear higher in the list. Let us change the order of the files in the iMOD Manager.

Now we should arrange files for TOP_SLD{i}_M and BOT_SLD{i}_M properly: layer 1 on top and layer 6 below.

It is important to place the IDF-files in the right order and to put together the top and bottom of each layer. Also, you can arrange files simultaneously by selecting them. It is faster to select multiple files and move them downwards to move the file underneath upwards.

Let us now make a cross section of the subsoil.

iMOD will display an empty graphical canvas, called the iMOD Cross-Section CHILD window, since no cross-section has defined yet. Let’s start drawing the location of the cross-section.

Whenever you move your mouse in the iMOD Cross-Section CHILD window, you’ll notice a circle on the line of the cross-section that directs to the current location in the cross-section. Once a cross-section has been drawn, you can adjust/manipulate it, let’s do that.

Let’s change the configuration of the cross-section, so our aquitards will be filled by different colours and our aquifers will become yellow.


Figure 11.23: Example of a vertical cross-section with single colour per aquitard (green) and aquifer (yellow).

Since this can be quite laborious, iMOD facilitates several display configurations that configure the table assuming the IDF-files are ordered in a particular manner (see Section 7.3.1). For this set of IDF files you might use the one below.

As you might observe, the cross-section gives a clear image of the subsurface. Moreover, the settings we just applied in the steps Item 27. until Item 42. are stored internally. Whenever you leave the Cross-Section Tool and re-enter it, these settings remain intact, except for the coordinates of the cross-section. Whenever you would like to re-use the same coordinates save them in the Miscellaneous tab on the Cross-Section Properties window, or alternatively save the last drawn cross-sections as a Demo-IMF (see section Section 7.1 for more information on this).

Let us try it.

Let’s us include some boreholes in the cross-section of the subsoil.

Observe that all settings are still intact and a vertical dashed line is drawn at the intermediate points. Moreover, all boreholes that are within a close range to the cross-sectional line, are projected perpendicular on the cross-section.

We need to tell iMOD to use a different colour legend for plotting the boreholes, just like we did in Section 11.1.

iMOD will redraw the cross-section using this renewed legend and will use this legend during your iMOD session.


Figure 11.24: Example of interactively generating a vertical cross-section of a 3D subsurface including boreholes.

Note: Boreholes within a user-specified horizontal distance from the cross-section are projected on the vertical cross-section; this specified distance is visualised by the thickness of the trajectory of the cross-section (red line) in the ’Draw Cross-section’ window. While drawing the trajectory of the cross-section in the ’Draw Cross-section’ window, the vertical cross-section through the subsurface is updated in the ’Cross-Section CHILD’ window simultaneously; when dragging an existing trajectory, the cross-section is updated as soon as the left mouse button is released.

3D Tool

The next step is to analyse these data in the 3D tool.


Figure 11.25: 3D Tool view of the subsurface and borehole data used in the previous 2D cross-section exercise.

iMOD offers the ability to select boreholes upon their length, whether they are within a predefined polygon and/or whether they agree with a specified query. Let’s make a query to display boreholes that intersect the third aquitard only described by the TOP_SDL3_M.IDF in the list of IDF files no the IDFs tab on the 3-D Tool window.

This window can be used to define all kind of selection criterion to exclude wells and/or part of wells. It can be defined for each of existing IPF files which are listed on the IPFs tab on 3D Tool window. For now, we configure this window to exclude boreholes that do not intersect our third aquitard.

The window should look as follows:


Figure 11.26: Example of the 3D IPF Settings window.

Let’s see what happened if we accept this query.

If you did it alright, the following image should appear in which it can be seen that only boreholes show up that actually intersect the interface [TOP_SDL3_M.IDF].


Figure 11.27: Example of the resulting selection of boreholes using a single clause.

Alternatively, it might be interesting to show from this set of boreholes, only those parts that contains the lithology [LOAM] and are below the TOP_SDL3_M.IDF interface, so we modify our existing clause and add another clause to our query.

The result will look as the example below. You only see the boreholes below [TOP_SDL3_M.IDF] and those parts that contains [L] (which is loam). All parts of each borehole that doesn’t match the query, are displayed in a white colour, as specified.


Figure 11.28: Example of the resulting selection of boreholes from two clauses.

Okay, let reset the query and continue with this tutorial with other cool stuff.

Let’s do something different. Let’s experiment with the fence-diagrams and clipping planes functionalities. First we switch to a full 3-D solid model.

In this mode, you’re able to actually draw a line on the 3D graphical canvas. If you move your mouse into that area, a red vertical line appear and a red dot. The red dot is the actual position of your mouse on the 3D image (actually the TOP_SDL3_M.IDF) and the x-,y- and z-coordinates are presented in the window status bar.

Well, that’s no too bad. Try to add another fence-diagram, the following figure shows what the result might be.


Figure 11.29: 3D Tool view of the subsurface and borehole data after drawing a fence diagram interactively.

Note: The colours in the fence diagram are the colours assigned to the individual IDF files; you can modify each of them individually via the IDF’s tab.

Remember that these cross-section file can be (re) used by the Solid Tool (see Tutorial 5, Section 11.5). Let’s apply some clipping planes.

Observe that once the clipping is active the subsurface model is torn open and it is possible to look into it. To avoid that it is possible to fill those openings with a solid colour. This is called capping.

For each entry in the 3D Tool, it is possible to exclude clipping. Let us do that for the lower part of our geological model.

That’s pretty fancy, so we can exclude the boreholes from the clipping as well.


Figure 11.30: 3D Tool view of the subsurface and borehole data after drawing a fence diagram interactively.

Note: iMOD uses a technique to count how many time pixels are drawn in order to decide whether that position need to be capped. If the number of IDF files is uneven, this might cause some undesired interferences. Also if you activate more than one clipping plane in combination with capping. Try that to see what happens.

Okay, that is enough in 3D, let’s go back.

Timeseries Let’s draw some time series interactively. In iMOD you need to open just one IDF-file that contains specific information about a date in its name notation, such as *_20101231_* to express the 31\({}^{th}\) of December 2010. Without having to open other files for other dates, iMOD searches for equivalent files, instead. Just as easy!

Observe that the current IDF has a non-equidistant network.

You could have specified a selection of the available IDF-files to decrease the initialisation time of iMOD to allocate the files. iMOD will read/open all available IDF-files from the same folder as the IDF-files that you’ve opened in step Item 116.. This could take several seconds, watch the progress in the status bar. Once this has finished the Draw Timeseries window will be displayed.


Figure 11.31: Screen shot of the ’Draw Timeseries’- and ’Timeseries Tool’-windows while hovering with the mouse over a map of a series of IDF-files.

Since iMOD will draw a time serie that can be computed within one second only, you might notice that not the entire time serie will be plotted within a single second. This can be seen in the progress bar on the bottom of the Draw Timeseries window. Whenever this might happen, you can left-click your mouse button to ”force“ iMOD to finalize the time serie completely.

As soon as the hovering has stopped you can examine the entire drawn time serie. Experiment with the variety of options on this window and within the different tabs. See section Section 7.2.1 for more detailed description of the available functionalities.

Alternatively, it is possible to create a 2D sequence of images and gather them into a ”movie“ file, see section Section 7.5 for more information in this and all the options. It is necessary to extend your IMOD_INIT.PRF file (see section Section 9.1) with the following keywords (which might have a different value in your particular case):

Example of a content of an iMOD_INIT.PRF file.

FFMPEG “D:\OSS\THIRD_PARTY_SOFTWARE\ffmpeg-3.3.1-win64-static\bin\ffmpeg.exe”
FFPLAY “d:\OSS\THIRD_PARTY_SOFTWARE\ffmpeg-3.3.1-win64-static\bin\ffplay.exe”
VLCPLAYER “C:\Program Files \(x86\)\VideoLAN\VLC\vlc.exe”

So, let’s create a simple movie of our hydraulic heads in 2D space.

Comparable to the Timeseries Tool you could skip particular time step in the sequence to reduce the number of images in the movie and/or to speed up the determination of the movie. It might be taking some time to generate all the images but it depends also the in the configuration. You should remember that you can create a movie that interchanges more IDF files per time step in combination with other that keep constantly. In that manner you can combine a dynamic sequence of drawdown in time with a static map that shows highlights in the area of interest, e.g. wet or dry areas or particular land-use categories. Also the combination with overlays and/or topographical images is possible. However, we keep it simple for now, but please feel free to experiment with this tool after finishing this tutorial.


Figure 11.32: Screen shot of the settings on the ’Available Dates’-window.

iMOD generate 294 images of the time series and saves these images in the folder \IMOD_USER \MOVIES \TEST as IMAGE{i}.BMP, where \(i\) is 1 up to 294. After that iMOD uses the program specified by FFMPEG to gather these images into an AVI file in the same folder called IMOD.AVI. This file can be played in iMOD as it will the AVI-player as specified at the keyword FFPLAY or VLCPLAYER.


Figure 11.33: Screen shot of the ’Play Existing Movie Files’-window.


Figure 11.34: Screen shot of the movie player as specified at the keyword VLCPLAYER.

At this stage, you can use all functionalities on the VLCPLAYER and examine the movie. If you believe the movie is showing the images to fast, try to apply different settings for Framerates or alternatively specify the Duration of each image.

That’s all folks for now! Enjoy this tutorial a bit more, or let’s create our first groundwater flow model in the next tutorial.