Generate Z Values
The Grid file must cover the X and Y range of the data points in the Output file. Points outside the Grid file range will not have Z values calculated.
Grid
File
Double-click to select the name of the Grid file you created in the Contours function.
Interpolation algorithm
Interpolation algorithms can be applied to improve the precision of the generated Z values in the grid. There are 3 options:
| Algorithm | Description |
|---|---|
| Nearest Neighbour | Selects the value of the nearest point. |
| Bilinear | Performs a linear interpolation on a 1-by-1 grid around the point, first in one direction, and then the other. |
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A Bilinear interpolation will generate Z values that closely match the height of the grid when it is displayed in 3D Shaded mode. |
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| Bicubic | Uses cubic splines to interpolate a 4-by-4 grid around the point. This algorithm will produce a better result than Bilinear, at the expense of processing speed. If one of the Bicubic nodes is undefined or lies on the boundary, the function will attempt to apply the Bilinear algorithm, or failing that, Nearest Neighbour. |
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Under some circumstances a Bicubic interpolation can overshoot the original data and this may cause data artefacts. Always validate Bicubic interpolation results before using them elsewhere in the application. |
Output
File
Enter the name of the Output file and apply a filter if necessary.
East and North and Z fields
Specify the names of the fields in which Easting, Northing, and Z coordinates will be stored in the Ooutput file. The Z field will be created if it does not exist.
Overwrite existing Z values
Select the Overwrite existing Z values option in order to replace existing Z values in the Output file. If the Overwrite check box is unchecked then the function will only overwrite values where the existing Z value is blank.
Forms
Click the Forms button to select and open a saved form set, or if a form set has been loaded, save the current form set.
Run
Finally, click the Run button to run the function.