Using the Forms Library package included with Geomview, a user interface was built to enable the user to make decisions regarding the display of an ECOPHYS tree (see figure to right). These decisions include selecting tree files to load, coloring leaves and roots based on attribute values, displaying or not displaying tree branches, roots, and/or the sunlight, and rendering two trees simultaneously for comparison purposes. Adding in the features provided by Geomview, this program provides a useful and effective way to visualize the data produced by the ECOPHYS model.

Overview of Program Features

Section 1 - Loading files
Files accepted by the visualization program are of the form *.eco. These files point the program to the three data files that hold the geometric data for that particular tree: the branches file, leaves file, and roots file. The visualization program reads in the tree information and processes it into data that Geomview can understand. This data is piped into Geomview by the program, which then displays the tree graphic.

To load a file, press either load button in Section 1 of the form. This will bring up a typical load window on which the user can browse through data files and choose one to load. Once a file has been loaded, it can be displayed at any time by pressing the "Update tree" button circled in the top right hand corner of the form. IMPORTANT: When the update button is pressed, it only updates the tree that is chosen in Section 5 of the form. So to display the file chosen for Tree 1, the "Tree 1" button must be pressed down. For more details, see Selecting trees below.

Section 2 - Leaf attributes
How the leaves are displayed for a tree is determined by the settings in Section 2 of the form. Five leaf attributes are implemented in the visualization program: gross photosynthate, percent shaded, LPI, ppfd-sun, and ppfd-shade. To choose an attribute to display, click on the "Type" field. Each time the field is clicked, the next choice in the list pops up. Once the end of the list is reached, it loops back to the beginning (a second option is to right-click on the choice field which causes a menu with all the options to appear). The "Min" and "Max" fields are the minimum and maximum value that are contained by the leaves for the selected leaf type (attribute). These values are automatically found for the loaded file when the leaf type is chosen (except for type normal). By changing these values, only the leaves with attribute values that fall within the new range are drawn. If these values are changed, the "Return" key must be pressed in order for the new values to take affect. **NOTE: the new minimum value must be larger than the original minimum value and the maximum smaller than the orginal maximum. The "Color" field selects the base color for the leaf coloring. Leaves that have the minimum value are colored black and those with the maximum are white. The leaves between are colored using darker shades of the chosen color for smaller values and lighter shades for larger ones. To change the minumum and maximum attribute values back to the original values for that tree, click on the "Reset" button. An example of a using red as the base color and gross psyn as the leaf type is rpsyn1-260-7.gif. **NOTE: when the leaf type is chosen as normal, the tree is always drawn with green leaves. Therefore, the "Min", "Max", and "Color" fields are disabled when "normal" is selected.

Section 3 - Root attributes
The visualization program allows roots to be colored according to root attributes in much the same way leaves are. At the present time, the user can select between three options: normal, double, diameter, order, and the rho angle. Choosing double causes the roots to be displayed with their diameters doubled. This is useful for taking pictures of a tree with its roots displayed, since the roots tend to look segmented when the window displaying the tree is small (see the Graphics page). The settings for root attributes are in Section 3 of the form and work exactly as the leaf attributes settings. Due to the large size of the root data files, the rendering of the roots takes a significantly longer amount of time than the other tree parts. It may be useful to display leaves as "normal" and not to display branches when using this option (see next section).

Section 4 - Other options
Branch options:
For large trees, a great amount of computation is required to render its branches. To further increase the speed and smoothness of rotations, translations, etc., the tree can be display with the branches hidden. The result is a non-cluttered, efficient way to view the position of the leaves. The branches are displayed by default. To turn them off, click on the top button in Section 4 of the form. Choosing "No branches" causes the tree to be displayed without branches, "Show branches" with branches. A tree with no branches is shown in rpsyn1-260-7.gif.

Roots option:
The root system for large trees is even more enormous and complex than the branches. This entails a large amount of computation. When only the above ground portion of the tree is needed, the roots can be removed. This cuts down computation time and allows for quicker and smoother transformations of the tree. By default, the program does not display the roots of the tree. To change this option, click on the middle button in Section 4 of the form. By choosing "Show roots" the tree will be rendered with roots, "No roots" excludes them.

Sunlight option:
It is sometimes useful to see which direction the sunlight is coming from in relation to a tree (for example, in comparing the same tree with leaves colored according to percent shaded). To select whether or not the sunlight is shown, click on the bottom button in section 4 of the form. The two choices, "Show sunlight" and "No sunlight", turn the sunlight option on and off, respectively.

Section 5 - Selecting trees
In order for comparisons to be made between trees generated by the ECOPHYS model, the visualization program allows two tree files to be displayed simultaneously. The files are loaded as described in Section 1. To make changes to the display settings, the button corresponding to that tree must be selected in Section 5 of the form. For instance, if the "Tree 1" button is selected, any changes made to the settings are only applied to tree 1. If the "Tree 2" button is then selected, the settings for tree 1 are automatically saved, and the settings for tree 2 will appear. It is important to remember that clicking on the update button will ONLY update the tree whose button is selected.