When you are gridding data, the gridding algorithm can calculate a Z range for the grid that extends beyond the Z range for the original data file. However, you have control over this using the Grid Z Limits section on the Output page of the Grid Data dialog.
You can allow the gridding method to determine the Z range in the grid, you can tell Surfer to match the Z range in the grid to the Z range in the data file, or you can enter a custom value for the grid Z range.
- Click Home | Grid Data | Grid Data.
- In the Grid Data - Select Data dialog, click Browse in the DataSet 1 field, select the data file to grid and click Open.
- Select the Gridding Method and the X, Y, and Z columns.
- Click Skip to End.
- On the Output page under the Grid Z Limits section, you can choose how you want Surfer to calculate the grid's Minimum and Maximum Z value. You can use different selections for the Minimum and Maximum (e.g. you can set Minimum to Custom and leave Maximum set to None). The options are:
- None. This allows the gridding method full control over calculating the Z minimum or maximum.
- Data min or Data max. This tells Surfer to use the minimum or maximum Z value in the data file as the maximum and minimum Z value in the resulting grid file.
- Custom. This allows you to specify a custom minimum or maximum Z value for the grid file. For example, if you know that there should be no negative values in the grid file, you can enter 0 as the Custom value for the Minimum.
- Click Finish and the grid is created with the Z range specified.
Updated October 2021