When you choose a string column for grouping, all unique values in that column is auto-populated. You can then select some or all of these populated values. Each unique value becomes a field in the MRR output or individual file in other output format.
Gridding or interpolation is always performed on the cell values. If you have your data in TAB file, you can open Browse window to see the columns in your input data source. First of all you will select those column on which you want to perform interpolation. After you have selected the column for interpolation, you can show result of interpolation by way of grouping. Grouping is done on rest of the columns in the file.
Grouping Input Data Based on String Column
On the Raster tab, in the Interpolate group, click Create Raster Multi-file or Create Raster. The Create Raster dialog box opens.
In the Select Columns drop-down list, select the column on which you want to perform interpolation.
button against the
Group field and then select the column for grouping. -
Select Columns - Select a column from your tabular data source. This field is auto-populated if you have selected columns on the main dialog box. You can change the column from the drop-down list.
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Available Items - This list shows all the unique values available for selection from the selected column. Use Add or Remove buttons to select items from this list.
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Selected Items - This list shows all the selected values. By default, all unique values are selected.
While generating output from grouping, choose MRR format if you want a single file containing all individual groups as bands of a field. If you choose .grd or other file format, individual files are created for each group.
At any point of time, you can click OK to go back to the main window to select other options and complete the gridding process.