When gridding a data set with numerous duplicate data points using the Modified Shepard's gridding method, sometimes the resulting grid contains unrealistic Z values that are far extrapolated from the z range in the data file (for example, values in the -268420 to 227897 range compared to a range of 3400 to 6600 in the data file). When this happens, the best solution is to apply a data filter during gridding. To do so:

1. In the Grid Data - Select Data dialog, click the Filter Data button.
2. Change the To Keep value in the Duplicate Data section to anything other than All.
3. Click OK.

Now you can proceed with setting the other gridding options as desired to create your grid, and the result should have a more appropriate z range.

Updated October 2021