Data Tree window
Use
the File menu to create a new, or open either a 1D and 2D model
data file. The data file for 1D and 2D model have extensions .oia
and .oib, respectively, and they
are saved as a normal text file. Rather than creating a new model file
from scratch, it is often easier to open a data file, make the necessary
changes and save the file as another file name. Once the file is created
or loaded, the Data Tree will display the model parameters and their values
as a tree format with expandable 
and collapsible 
branches. Users have two options to change the value of a model parameter.
The first is to make direct changes in the Data Edit window, and the second
is to select the value of the model parameter, and to double-click or
hit the Enter key. For the second option, a dialog box will appear
and prompt for user input.
Data Tree uses several symbols to denote the type value a model parameter requires. The symbols used are:
denotes a float-type, e.g., 0.15, 1.0, 2.2, 3.5, etc.
denotes an integer, e.g., 0, 1, 2, 3, etc.
denotes a file pathname, e.g., "c:/model/data/weather99.dat".
denotes a string, e.g., "maize".
denotes a one-dimensional series of float-type values.
denotes a two-dimensional series of float-type values, or pairs of (x,
y) values.
In addition, certain
tree branches can be deleted and inserted. These tree branches are denoted
by the grey symbols 
and 
.
To delete a tree branch, select the tree branch that has the symbol
or ,
and hit the Delete button, or choose the Delete command
from the Data menu. Likewise, to insert a tree branch, select the
desired location and press the Insert button, or choose the Insert
command from the Data menu. Note only certain tree branches allow
insertions and deletions, such as the Intercrop tree branch where users
can insert Crop tree branches. Insertion and deletion are explained more
in detail in this section.
Whenever the model is modified in any way (e.g., modifications of parameter values, or insertions or deletions of tree branches), x-model will always save the data from the Data Tree into a file and reload the model data file before a Run command is executed. Because of these two file operations, there will be a slight delay before any Run command is executed. Users can determine if the model has been modified by the INIT flag on the statusbar (see statusbar at the bottom of Fig. 1). If INIT flag does not appear on the statusbar the model is unchanged. Also note that when a model is first created or first loaded from a file the model is considered modified as well.