The accuracy of a model is increased when the orthogonality of a grid is optimized. A perfect grid would have all cells perpendicular to the boundary lines. This is very difficult to achieve and thus for most EFDC models an orthogonality of under 3o is recommended. The orthogonalization tool is used to reduce the orthogonal deviation of a grid.
To view the orthogonal deviation of a grid, LMC on the grid layer in the Layer Control then RMC on that grid layer to show RMC's options, select Show Properties/Orthogonal Deviation as shown in Figure 1. In addition, the orthogonal deviation of a grid can be viewed from the Grid menu as shown in Figure 2.
Figure 1 View orthogonal deviation of a grid from RMC's option.
Figure 2 View orthogonal deviation of a grid from Grid menu.
Figure 3 Orthogonal deviation of a grid.
There are two options for orthogonalizing grid: Othogonalize entire grid and Othogonalize grid block as described below:
Othogonalize entire grid
- Select the grid layer in the Layer Control by LMC
- From Grid menu, select Orthogonalize Grid or the user can click on the Orthogonalize grid button from the main toolbar as shown in Figure 4. As a result, the entire grid will be orthogonalized immediately.
Figure 5 shows orthogonality change of the grid after applying Orthogonalize Grid. If the user keeps using the option, an informing message will appear when the orthogonality reaches a limitation as shown in Figure 6, click OK button to exit the form.
Figure 4 Orthogonalize grid.
Figure 5 Grid image after applying "Orthogonalize Grid"
Figure 6 Message informs the orthogonality reaches a limitation.
Othogonalize grid block
- Select the grid layer in the Layer Control by LMC
- From main toolbar, select the Select object button then select a grid node, hold Shift key and select the second grid node. The grid block will be highlighted as shown Figure 7.
- Next, from Grid menu, select Orthogonalize Grid or the user can click on the Orthogonalize grid button from the main toolbar. In the other hand, the user also can select Orthogonalize Grid Block from RMC's options as shown in Figure 8. As a result, the grid block will be orthogonalized immediately. Figure 9 shows orthogonality change of the grid after applying Orthogonalize Grid for a grid block.
Figure 7 Select a grid block.
Figure 8 Select Orthogonalize Grid Block option.
Figure 9 Grid image after applying "Orthogonalize Grid Block"