WIMOVAC Central Graphing Module

When the start button (Figure 7iv) on the model dialog is selected wimovac executes the program code that contains a symbolic representation of the model system under investigation. If the model code requires more than a few seconds in order to finish a progress bar is shown. Upon completion of a simulation run wimovac loads the graphing module as a child window and transfers over the results of the simulation to the graph. The graphing module is central to results handling in wimovac and provides an automatically formatted graph, with labelling and scaling performed from information gathered from the model dialog at the start of the simulation run.

The graphing module generally defaults to a simple line graph of the results but using the appearance-gallery menu option (Figure 12iv) on the graph form or by selecting one of the graph toolbar buttons a number of graph types can be chosen (Figure 11ii). These include 2D and 3D pie, line and area charts in addition to gantt, log, scatter, polar, bubble, candle stick, box whisker, time series and tape charts. The graphing module also offers a number of curve fitting functions as standard including 1-9^th order polynomial fitting, logarithmic, power, exponential and inverse curve fits.

The graphing module offers only limited scope to modify the font selection and sizes used to label output graphs and so is not intended to provide a replacement for packages designed to produce publication quality graphs, but rather to provide an easily interpreted visual representation of the simulation results. In order to facilitate communication between the graphing module and other packages wimovac incorporates a menu option that allows a copy of the simulation results to be passed to other applications via the Windows clipboard (Figure 12ii).

The results may be passed in either a columnar, tab-delimited format suitable for use within a spreadsheet or as a graphical image. Wimovac supports both standard and device independent bitmaps and offers the option to use the scaleable Windows metafile format (Figure 12ii).

Figure 11. Wimovac central graph control. i) Context sensitive graph control properties panel displayed when a button on the toolbar (v) is selected. ii) Selecting buttons on the control panel modifies graph properties. iii). Tab control used to give access to multiple controls in a small screen area. iv). Graph control showing 3D surface results from the optimum conditions for assimilation module. v) Graph control toolbar gives access to the control panel. Includes tooltipsÔ which explain the button function when the cursor is positioned over the button for a few seconds. vi) Graph output is labeled and includes left (vii), bottom (viii) and legend (vi) information where appropriate.

The graphing module is also able to create an ASCII data file of simulation results. By default this is a tab delimited columnar file that can be conveniently read by both MS-DOS and Windows based spreadsheet and graphics programs (Figure 12ii). The information in each column is determined by user selection of options on the module dialog form. Titles are introduced to the top of the file to indicate the nature of the data in the file and to each individual column to indicate the contents of a given column. In addition to this wimovac is able to save a graphical image of the graph to disk in either bitmap or metafile image.

Figure 12. Graph control menu structure displayed on the parent window menu line.

The graphing module is capable of printing in either landscape or portrait mode in either monochrome, dithered colour, or full colour to any Windows supported printer. A Windows common printer dialog procedure built into wimovac makes it possible to select printer and output characteristics prior to printing (Figure 12i). It is possible to view the exact numerical data represented in a graph by selecting the Data menu followed by the View data table option or by using the copy data option on the edit menu to transfer the data to a spreadsheet program (Figure 12iii).

Under normal conditions the graphing module plots only the results selected in the model dialog. If after reviewing the results further parameters need to be plotted, for the same simulation conditions, the model must be run again. This approach is simple but would be undesirable with long simulation runs. The graphing module is augmented however by an optional simulation results datafile which can be initialised by a switch in the parameter database. The results datafile is created as the vegetation model runs and contains an output of all model parameters at every simulated time interval. Clicking on the Select datasets menu option (Figure 12iii) displays a dialog which allows any model output to be plotted against any other output or set of outputs without having to re-run the model.

Figure 13. The select datasets dialog in wimovac. i) X axis parameter category selector. The context sensitive list (ii) displays an appropriate list of parameters for the selected parameter category. iii) By default the results are plotted as a non continuous XY scatter graph, checking this box plots the results as a continuous line graph. iv) Y axis parameter category selector. v) Y axis parameters to be plotted. Multiple choices may be selected by dragging with the mouse or depressing the CTRL key whilst making selections. Dialog selections shown will plot the assimilation rate in the top 5 canopy layers against simulation time.

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Last modified: August 19, 1997