Simile can extract a 2-dimensional array of data from an image file, with each pixel in the image corresponding to a datapoint. The image can be in any format supported by the Tkimg package, which is to say, most of them.

If you have a .csv file with a 2-dimensional grid of data items, this can be loaded directly into a 2-dimensional array file parameter in Simile. For other 2-D formats that can be read into a spreadsheet, you can create the .csv file.

Once you have specified the data for all the file parameters, you can save that data in a scenario file (extension .spf, sometimes referred to as a parameter metafile). This file does not necessarily contain the actual data, it can contain references to the files that actually contain the data. It is in an XML format, allowing it to be examined and edited if required.

Ther normal way to use the file parameter system is to create and save references to data in other files. To do this, click the 'pencil' icon to the right of the data entry field. This brings up the table data dialogue, which allows you to specify the file containing the data, and how to get the data from the file.

Once this has been done, hovering over the entry field will produce a popup showing which file contains the actual data. Hitting the 'pencil' button again will show the reference information and allow it to be altered.

The File Parameters dialogue will contain entry fields for both fixed and variable parameters. Fixed parameters must be given a value; their captions in the dialogue will be shown in red until a correctly formatted value has been supplied. Variable parameters do not need a value, and can be left empty, so the value can be set by a slider while running the model. However, it is possible to enter a time series in the File Parameters dialogue, which will cause the variable parameter's value to be set at a series of specified time points while the model is running.

The simplest way to set a file parameter is to type its value straight into the entry box beside its caption in the file parameter dialogue. For single values, this is the only way to enter them initially. The tick button replaces the currently saved value with what has been typed in, while the cross button reverts the entry field to the saved value.

The Table Data dialogue is used to specify how to extract data from a file of any one of a number of formats so that it can be used in a Simile component. Its main use is for getting data for file parameters, but it also appears when creating a table function that is built into a component's equation.

There are four tabs in the dialogue, corresponding to the four varieties of supported data format. These are:

The File Parameter dialogue allows the modeller to specify where every parameter in the model gets its values from. It contains an entry box for each parameter, which displays the values associated with it, and when you hover over it it pops up information about where those values come from. Hovering over the parameter captions, listed to the left of the entry fields, displays the units and dimensions of the required data. Simple values can be typed in directly, while long lists can be loaded from data files.

Submodels with one instance per data record

It may be that you want to run your model with many different datasets, and these datasets each have different numbers of records which are supposed to correspond to instances of a submodel. Or perhaps you have nested submodels, where the membership of the inner submodel is different in each instance of the outer submodel, with the actual memberships being determined by the numbering of data records in a file.

Polygon diagram

This tool enables a dataset to be displayed as the colours of polygonal areas on a map. It can be used either where vector data for an actual map is available (either in the model, or in a separate file), or where an area is represented as some regular set of shapes whose vertices can be calculated by the model, e.g. hexagonal tiling.