The grid Dimensions options are used to establish the boundary coordinates and the number of nodes to be created in the grid model. These settings are available in all program windows where grid models are created.
- Based on Project Dimensions: Choose this option if the grid dimensions are to be taken from the current Grid & Model Dimensions settings.
This is generally a good idea, particularly in projects where multiple models are going to be created and may need to undergo comparison, mathematical, and filtering operations (in which all models must be dimensioned the same).
- Project Dimensions: You'll see the current project dimensions displayed here. Click here for more information.
- Variable: Based on Range of Input Data: Choose this option if the grid dimensions are to be established based on the current data being modeled.
This could be an option for modeling a subset of the entire project or for testing the effect of different node densities without having to reset the entire project's dimensions settings.
- Average Minimum Distance Between Control Points: Choose this option to set grid dimension defaults based the average minimum distance between control points or boreholes.
- Scalar: If you choose Average Minimum Distance and enter a scaler of "0.5" the grid node spacing will default to one-half (0.5) the average control point distance, delivering an average of 2 nodes between control points. If you enter a scaler of "0.1" the grid node spacing will default to one-tenth (0.1) the average control point distance, resulting in an average of 10 nodes between control points.
This works well for densely-spaced data. This will create very coarse grid models with sparse data. The boundary defaults will correspond to the outermost control point locations.
- Manually Specify Number of Nodes: Choose this option to set grid dimension defaults based on a constant value you enter. For example, if you enter 50, the grid will have 50 nodes from north to south and 50 nodes from east to west. The boundary defaults will correspond to the outermost control point locations.
- The number of nodes you declare will be modified if the map area is not square. In trying to keep node spacing as close to equal as possible along both axes, the program will reduce the number of nodes created along the area's short axis. If you request Confirm Dimensions, below, you will have the opportunity to view and confirm the program-recommended node spacing prior to model generation.
- The more nodes you specify, the denser the model. The more computations the program needs to do, the longer the time required to create the model. Denser is not always better. You might create less-dense models on trial runs.
- Current: Choose this option to have grid dimensions set to the same boundary coordinates and spacing as were used in the last gridding session - the program will not scan the source data to compute new boundaries and spacing. This can be handy if you are creating successive grid models and you want them all to have the exact same boundary coordinates and node spacing and you don't wish to use the fixed Output Dimensions.
- Confirm Dimensions: Check this box if you wish to review the dimensions settings prior to generating the grid model. If activated, the program will display a confirmation window after you've established all of the menu settings and have clicked the Continue button to proceed.
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