iMOD User Manual version 4.4 (html)

4.2Create a GEN-file

A GEN in iMOD is a BINARY file format (see Section 9.11) that contains coordinates in double precision as well as label information. It replaces the old ASCII GEN format in combination with a DAT file. iMOD can read the old ASCII GEN file, however, the functionality of having a GEN and DAT file has become obsolete. There is an option to import the old ASCII GEN and DAT file and convert it into the new BINARY format via File, the option Import and than the option Import ESRI GEN file.

Select the main option Edit and then choose the option Create Features and then the option GENs to display the Create GENs window. Create GENs window.



Draw Polygon
Click this button to start drawing a polygon on the canvas, see Section 4.3 for more details on drawing polygons. First you need to select the type of shape you want to draw from the Select window:

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This window shows the available type of topology to supported by the binary GEN file format.


Click this option to define startpoints for a single point


Click this option to define a rectangle.


Click this option to define a polygon.


Click this option to define startpoints on a circle


Click this option to define a line.


Click this button to start drawing a line that intersects current lines/ polygons or rectangles to split the intersected segments accordingly into separate lines.


Open File
Click this button to open a *.GEN file, this can be an ASCII GEN file or a BINARY GEN file. iMOD will not read in associated DAT files from the old ASCII GEN files. If needed, those need to be converted to a BINARY format priorly via File, option Import and than the option Import ESRI GEN file. iMOD recognizes whether the GEN file is the old ASCII or new BINARY format, automatically.


Save File
Click this button to save the polygons to an ASCII or BINARY *.GEN-file (see Section 9.9). iMOD will save the names for the individual features in the *.GEN too. Those will be read whenever those files are read in iMOD again whenever the button Open File is selected.


Delete Polygon
Click this button to delete the selected polygons from the list. This action can not be undone, however, you will be asked first whether you are sure to delete the polygons.


Rename Shape
Click this button to rename the selected shape, the Input window will appear:

Example of the Input window

target="_blank" >pictures/h1-h3/image107.png

You can enter a different name for the current selected polygon. Click the button OK to accept your entry, or click Cancel to leave the name unchanged. In both cases you will return to the Create GENs window again.


Click this button to adjust the zoomlevel to the selected shapes.


Click this button to open theAttributes Values window:

Example of the Attributes Values window


This window shows the attribute values of the selected shapes.


Insert attribute
Add an attribute to the shapes.


The following options are available

Give an Attribute name
Enter the name of the current attribute. There is maximum of 11 characters to specify this label

Width of Attribute
Enter the width of the attribute in characters, numbers will be saved as characters as well. Via the Rename Attribute option it is possible to change the width of the attribute, however, bear in mind that decreasing a width afterwards, might remove data as well.


Remove attribute
Remove the selected attribute.


Rename Attribute
Change the name of the selected attribute, see the description at Insert Attribute.

Use following
column for gridding /interpolation:

Check the box and select the attribute name from the pull down list in case interpolation is to be done for an attribute different from the SHAPEID.


Make the changes in the shapes.


Select in Polygon
Click this button to create a polygon for which all polygons, lines and/or poins will be selected that are within the polygon. Start drawing the polygon by clicking your left mouse button at the first point of the polygon, click left for each additional polygon point and stop drawing by clicking your right mouse button. After that iMOD will select all topologies within the polygon.

Help ...

Click this button to start the iMOD Help Functionality (if available in the selected *.PRF file).

Close ...

Click this button to close the Create GENs window, you will be asked to save your shapes first.

Note: The functionalities mentioned above appear throughout iMOD in different windows. The behavior for each of those is similar as explained above.