iMOD supports several basic functionalities that manipulate IDF-files:
• IDF Value,
• IDF Export,
• IDF Calculator, use this tool to apply simple algebra, rescale the IDF and/or merge several IDF-file into a single one.
• IDF Edit, use this tool to select areas for which computations are carried out. These can be simple algebraic computations and/or smoothing and/or interpolation.
WHY?
IDF-files are raster files with (non)-equidistant rastersizes. Interactive inspection of the raster with the IDF Value option is a quick and easy way to check the raster values.
WHAT?
IDF Value allows you to view particular rastercell values for a single IDF-file, or multiple IDF-files. iMOD will read the IDF values underneath the current mouse position.
HOW?
In the Map tab of the iMOD Manager window, click the Map Value (
) button to open the Map Value window. Otherwise, use the shortcut F3 or right-click anywhere on the canvas to open the popup menu. Select the option IDF Options and then choose IDF Analyse. Or alternatively, select the menu option Map, choose the option IDF Options and then IDF Analyse.
Map Value Window:
Current Location |
This field shows the current location of the mouse on the canvas. Press the LEFT mouse button to freeze the current location. Restart inspection over the canvas by pressing the LEFT mouse button again. |
IDF |
This column in the table shows the IDF selected in the iMOD Manager and part of the inspection with MapValue. |
Values |
This column shows the value of the IDF (column 1) for the current location. Values that are greater than zero will be coloured red, less than zero become blue. |
Transf. |
This column shows the transformation that could take place, see for more information about this the syntax of the IDF-file and how to apply a transformation. |
Cell |
This column shows the column and row number of the selected IDF-files, e.g. Cell Indices=C32;R12 to represent column 32 and row 12 respectively. There is no need that the inspected IDF-files have identical dimension and/or raster discretization. Whenever the mouse is positioned outside the limits of the IDF, Cell Indices=Outside. In case the inspector works with a rectangle/polygon, the Cell Indices will show the minimum and maximum values for the column and row numbers that are within the rectangle/polygon, e.g. Cell Indices=C40-32;R32-54. |
Value Format: |
Choose the preferred value format from the dropdown menu. You can choose from: Real (e.g. 2.345), Integer (e.g. 002) and Scientific notation (0.2345E+01). |
Decimal places: |
Change this value to set the total amount of decimal values (values behind the point), the possible range is 0-15. |
Help … |
Click this button to start the iMOD Help Functionality. |
Close |
Click this button to close the MapValue window. Alternatively the MapValue window can be closed by clicking the RIGHT mouse button anywhere on the canvas. |
Note: All selected files in the iMOD Manager will be listed in the Map Value window, however, IPFs, IFFs, GENs and ISGs will be left out automatically. There is no need to deselect them before clicking the Map Value button. Whenever a MDF-file is selected, all IDF-files within the MDF-file will be displayed and also the MDF-filename.
Map Value window filled with items from a MDF-file:
Note: The menu options Move, Zoom In, Zoom Out, Zoom Full and Zoom Rectangle are available during the Map Value exercise.
Note: Click the left mouse button to stop hovering over the graphical display. It will freeze the values in the Map Value window. Start hovering again by clicking the left mouse button again, terminate the entire functionality by clicking the right mouse button.
On default, the Map Value window will operate as a point inspector, in other words, the value will be read for the current position of the mouse. Click the menu option Map, the option IDF Options and then the option IDF Analyse to display the following options to alter this:
• Plot No Location
Check this item whenever no rastercells of the selected IDF-file need to be displayed.
• Plot All Locations
Check this item whenever the rastercells of all selected IDF-files need to be displayed. Bear in mind that the performance will slow down whenever many IDF-files are included, and if IDF-files with non-equidistant rasters are included. Whenever this option is checked, all values in Map Value will be coloured differently.
Map Value window in Plot All Locations mode:
• Plot First Location Only
Check this item whenever the rastercells of the first IDF-file listed in the Map Value table, need to be displayed. This is the default.
• Points
Check this item whenever the values for the current location of the mouse need to be listed. This is the default.
• Rectangle
Check this item whenever the values need to be summed within a rectangle that you can draw. Use the left mouse button to locate the first position of the rectangle and the left/right mouse button to stop and close the Map Value window.
• Polygon
Check this item whenever the values need to be summed within a polygon that you can draw. Use the left mouse button to locate the first position of the polygon and continue to add more points (as desired) to complete the polygon. Use the right mouse button to stop and close the Map Value window.
• Circle
Check this item whenever the values need to be summed within a circle that you can draw. Use the left mouse button to locate the first position of the circle and expand the size of the circle while moving the mouse pointer away from the first position (centre of the circle). Click again on your left mouse button to stop and close the Map Value window.
WHY?
IDF-files have a specific format. The export to a format readable in other software applications makes it possible to use the IDF-files outside iMOD.
WHAT?
The IDF-files can be exported in several formats.
HOW?
Choose the option Map from the main menu, choose IDF Options and then IDF Export to display the following menu options:
• ESRI ASC Format
Check this option to export the IDF into an ESRI ASCII format. Bear in mind that this ESRI ASCII format does not support non-equidistant cell sizes. Therefore, the export will result always in an equidistant ASCII file, see section 9.14 for the exact syntax of an ESRI-ASCII file. Any ASCII file can be read in again in iMOD to convert is back to an IDF file, see section 6.1.
• NetCDF Format
Check this option to export the IDF into the NetCDF3 format. Any NetCDF file can be read in again in iMOD to convert is back to an IDF file, see section 6.1. This function is only available in the X32-bits version of iMOD.
For both export formats the following options are available:
• Export Total Extent
Click this option to export the current IDF for its total extent.
• Export Current Extent
Click this option to export the current IDF for the current extent of the graphical window.
• Export Given Extent
Click this option to export the current IDF for an extent to be entered.
WHY?
Arithmetic operations enable the creation of new IDF-files.
WHAT?
The IDF Calculator works with IDF-files as input and enables to:
• calculate a new IDF-file using an arithmetic expression on one or two IDF-files (the Algebra tab)
• change the rastersize of an IDF-file by upscaling or downscaling (the Scale/Size tab)
• merge a selected number of IDF-files into one IDF-files (the Special tab).
HOW?
The IDF Calculator can be displayed at any time from the iMOD Manager, click the Calculator button and/or use the Map option from the main menu (or the popup menu that displays whenever you click your right mouse button on the graphical window), choose IDF Options and then the option IDF Calculate. The following Map Operations window will be displayed.
Map Operation window, Algebra tab:
Map Operation window, Scale/Size tab:
Map Operation window, Special tab:
Function |
Select one of the following functions:
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IDF-files: |
Select more than one IDF-file to be merged. iMOD will calculate values for the overlapping areas based on the inverse distance to the extent border of the IDF-files. The weigh-factor for an IDF-file, increases whenever the point considered, lies further away from the extent border of the IDF-file. Exact in the middle between two IDF-files, the weigh-factors for both will become 0.5. |
Mask |
Select this option to include a mask that determines the area to be merged, e.g. a boundary of catchment area. This option is only available whenever Function=MERGE. |
Mask File: |
Enter the IDF-file of the mask. All data in the IDF, not equal to the NoDataValue will be used to identify the size of the mask. |
Open IDF-file |
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Result: |
Enter the name of the IDF-file to be created. |
Compute... |
Click this button to start the computation, it closes the Map Operations window afterwards. |
Help ... |
Click this button to start the iMOD Help Functionality. |
Close |
Click this button to close the Map Operations window. |
Note: It is allowed only to merge equidistant IDF-files (IEQ=0, see section 9.5).
WHY?
IDF-files are raster files with (non)-equidistant rastersizes. Normal GIS systems can not manipulate raster files in an easy way, moreover, it is difficult to edit individual raster cells.
WHAT?
The values of individual rastercells can be easily altered by selecting the rastercells and assigning a new value using the Calculate option. Also cell sizes of existing IDFs can be altered easily by grid refinement using upscaling and downscaling techniques.
IDF Edit allows you to select particular rastercells inside an IDF-file based on a maximum of two logical expressions that optionally operate inside a polygon. Logical expressions can be carried out sequentially. Once a selection has been made, different values can be assigned to them directly, or an interpolation and/or smoothing algorithm can be applied. A selection is carried out for mid points of rastercells for a particular IDF (Selection IDF). Those midpoints will be used also to perturb corresponding raster cells for IDF-files with different rastersizes and/or position. For these cases, it should be known that not all of the rastercells are affected by the alteration due to intermediate cells that are in-between midpoints of the Selection IDF.
Methodology of selecting and calculating with IDF Edit:
HOW?
To start IDF Edit select Map from the main menu, choose IDF Options and then IDF Edit. Alternatively, you can select the menu item from the popup menu that appears when you right-click your mouse in the graphical window. In both cases, you should select at least one IDF from the iMOD Manager, the IDF Edit window will appear.
IDF Edit window, Selection tab, (left) initial window, (right) after selection:
Shapes |
This groupbox contains several functionalities that are needed to draw and open polygons. The functionalities are explained in detail at section 4.2. | |
Use selected IDF |
Select one of the IDF-files listed in the dropdown menu. The content of the list is based on the list of IDF-files in the iMOD Manager. The dimensions of the file that you select will be used to display the selection. This file will be the Selection IDF. If you select a Selection IDF with cell sizes of 25 x 25 meter, the selection will be displayed on that dimension. It is only possible to change the Selection IDF if the current selection is cleared and/or is empty, click the Clear button to reset the selection and activate this dropdown menu again. | |
Select … |
Click this button to start the IDF Edit Select window. In this window it is possible to select specific cells onto the selected IDF. Example of the IDF Select window ![]() |
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IDF-file: |
Select one of the IDF-files listed in the dropdown menu. |
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Skip NoDataValue (…) |
Select this checkbox to “skip” the NoDataValues in the selection. On default this will be turned on, so cells with NoDataValues will not be selected, discarding their values. For the selected IDF-file, the current NoDataValue will be displayed between brackets. |
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Logic |
Select one of the logic variables out of the dropdown menu: |
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Value |
Enter the value to be evaluated, e.g. 11.230 or -5.400 |
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Include extra |
Select this checkbox to add an extra IDF to be evaluated for the selection. You can choose the keywords: |
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New |
Select this option to start a new selection. |
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Add to |
Select this option to add the results of the evaluation to the current selection set. |
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Delete from |
Select this option to delete the results of the evaluation from the current selection set. |
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Subset |
Select this option to take the result of the evaluation from the selection that is already in the selection set. |
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Select for Polygon |
Select this checkbox to apply the evaluation inside the current polygon(s) only. This option is active whenever a shape is selected in the IDF Edit window. |
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553 cells selected |
This shows the current number of selected cells 553 in the Selection IDF that consists of 19456 cells. |
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Clear … |
Click this button to clear the entire selection for the Selection IDF. This button is only available whenever cells are selected. You will be asked whether you are sure to continue. |
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Get Selection |
Select this button to get the selection. Each selection will be saved in the file: {USER}\TMP\{USERNAME}_TMPSELECTED{i}.DAT. |
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Undo |
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Zoom to Selection |
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Show Selection |
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Help ... |
Click this button to start the iMOD Help Functionality. |
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Close |
Click this button to close the IDF Edit window. |
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Trace … |
Click this button to start the IDF Edit Pipet window. The trace selection will select cells in the IDF on the basis of their value and their connection to the identified cell. In this way it is possible to select cells which are connected to each other in a particular manner. IDF Edit Pipet window: ![]() |
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Values should be |
Choose the selection condition from the pull down list. |
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Search |
Check one of the following options to specify how iMOD searches in 2D spatially. |
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Select |
Click this button to start the selection. The cursor will change in a pipette. Left click your mouse to select the cell from where you want to find the connecting cells which fulfil the selection condition. The IDF Edit Pipet window will close and the number of selected cells is indicated in the IDF Edit window. Click this button again if you like to start a new selection with new criteria and cell value (shown in the message bar at the bottom of your window IDF-value:{value}). |
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New |
Select this option to start a new selection. After a selection is made a new (clean) selection can only be started by clicking on the Select Location on Map … button. The selected cells will only than be deselected and a new selection can be made. |
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Add to |
Select this option to add the results of the evaluation to the current selection set. |
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Delete From |
Select this option to delete the results of the evaluation from the current selection set. |
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Subset |
Select this option to take the result of the evaluation from the selection that is already in the selection set. |
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Draw … |
Click this button to start the IDF Edit Draw window. Cells from the selected IDF can be selected or deselected interactively in the graphical window. IDF Edit Draw window ![]() |
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Add Cells |
Click this button to add cells to the selection. Use the left mouse button and drag the cells you want to select on the graphical window. Release the left mouse button to stop drawing and click the left mouse again to add more cells to the selection. |
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Remove Cells |
Click this button to remove current cells from the selection. Use the left mouse button to deselect cells from the current selection. Release the left mouse button to stop deselecting cells and click the right mouse button again to deselect more. |
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Clear … |
Click this button to clear the entire selection for the Selection IDF. You will be asked whether you are sure to continue. |
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16147 cells |
This shows the current number of selected cells (16147) in the SelectionIDF that consists of 22400 cells. |
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Help … |
Click this button to start the iMOD Help Functionality. |
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Close |
Click this button to close the IDF Edit Draw window. |
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Clear |
Click this button to clear the entire selection for the Selection IDF. This button is only available whenever cells are selected. You will be asked whether you are sure to continue. Question window: ![]() |
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Calculate … |
Click this button to start the IDF Edit Calculation window. This option is not active whenever nothing is selected. First the calculation method is defined in the upper part of the window, thereafter, the IDF on which the calculation is applied is selected in the lower part of the window. Note Whenever you click the Calculation button, the IDF-file will be adjusted and the new results will be saved directly in the IDF-file. You can use the Map Value option, to inspect the adjusted results, without leaving the IDF Edit
Calculation window. IDF Edit Calculation window ![]() |
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NoDataValue |
Select this option to apply NoDataValues |
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New Value |
Select this option to enter a new value. Choose one of the following options from the dropdown menu: |
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Copy Values |
Select this option to copy the values from the selected IDF-file in the dropdown menu. The IDF-files are those that are available in the menu on theiMOD Manager. |
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Smooth |
Select this option to smooth the values within the selection only. |
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Buffersize around (row/column): |
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Apply smoothing for following times: |
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Interpolate |
Select one of the following options to interpolate: |
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Properties |
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Table from: |
Select this option to open a table (Table Display) that shows the cell values in the selected cells for the IDF-file selected in the dropdown menu (right). |
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Display Table |
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Colour columns … |
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Column Width |
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Apply … |
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Close … |
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Available |
Select the IDF-file that need to be adjusted from the dropdown list. |
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Create a New |
Select this option to enter a different IDF file (not yet loaded in the iMOD Manager and/or to be created. |
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Save As |
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Calculate |
Select this button to execute the calculation and to adjust the values in the selected IDF-file. |
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UndoClick this button to undo the last calculation. Each calculation will be saved in the file: {USER}\TMP\{USERNAME}TMPCOMPUTED{i}.DAT. |
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Show Selection |
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Help … |
Click this button to start the iMOD Help Functionality. |
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Close … |
Click this button to close the IDF Edit Calculation window. If you have adjusted one/more files, you will be asked whether you are sure to leave the IDF Edit Calculation window. Changes can not be restored once you have agreed upon closing the IDF Edit Calculation window. |
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Show Selection Click this checkbox to display the selection. |
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Zoom Selection Click this button to adjust the zoomlevel to the selected cells. |
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Help … |
Click this button to start the iMOD Help Functionality. | |
Close |
Click this button to close the IDF Edit window. | |
IDF Edit window, GridRefinement tab:
Click this button to assign a new grid size. The Enter Value window will open. |
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Reshape selected IDF file |
Select the IDF file from the dropdown menu. |
Upscale algorithm |
Select the upscaling methodology from the dropdown menu; more detail about the available methodologies is given in section 6.7.3 |
Downscale |
Select the downscaling methodology from the dropdown menu; more detail about the available methodologies is given in section 6.7.3 |
Resize … |
Click this button to resize and save the IDF-file. |
Help … |
Click this button to start the iMOD Help Functionality. |
Close |
Click this button to close the IDF Edit window. |