Datamine Discover KB - Create Grid

I cannot select my data field/column for gridding

kbadmin — Mon, 19 Jan 2009 23:55:51 GMT

Occurrence

When I open my table in Surfaces>Create Grid, I cannot select some of my fields to grid.

Solution

The create grid tool only supports numeric fields types for gridding.
If you have numerical data in a Char field, you will need to change this under Table>Maintenance>Structure into a numeric field type, such as Float.

Note: if you character field contains any character entries such a '<0.05' or 'BDL', these will be lost upon conversion to a numeric field. Use Discover's Data Utilities>Select by Group to evaluate the contents of your character fields prior to conversion, and if necessary the Data Utilities>Text Search and Replace tool.

What does the Breaklines option in the Gridding tool do?

Josh Knight — Tue, 17 Jun 2008 05:24:34 GMT

The breakline feature in the Gridding tool allows the easy introduction of interpretive data points into the gridding process, without modifying the original dataset. Users can then enhance terrain trends such as ridge lines, valleys and rivers that are not well sampled in the data. For example, a fault trend can be added by placing two sub-parallel breaklines with different elevations in a data gap where you have inferred the fault location.

By incorporating break lines into the gridding procedure you can ensure that the output grid conforms to certain slope requirements in critical areas.

To load break line data, access the Breakline Advanced Options dialog from the Breaklines button on the Input property page.

The breaklines dialog allows you to browse to and select an input MapInfo Professional .TAB file. Only one input file can be selected. To identify the lines it is necessary to select a LINE field from the .TAB file. All vertices from all features with the same LINE identifier are considered to be a single break line. This means points can be grouped into polylines but it also means that polylines need to have a unique LINE identifier if they are to be considered unique lines. Also, select the Z field. It is assumed that the Z data are compatible with the data field you have selected to grid on the Input property page.

The break line information is then incorporated into the input data and is automatically used in all available gridding algorithms.

What do the �Near� and �Far� parameters of the �Clip to input area� section of the Gridding Tool > Output tab represent?

Josh Knight — Mon, 21 May 2007 06:17:00 GMT

The “Clip to input area” will clip a grid back to the area covered by the input data. You would only
use this when you create a grid using data which is in an irregular shape (i.e. not square) and the
gridding method (eg. triangulation) has interpolated over large empty gaps.

When you enter a Near or Far value the grid over the empty spaces is clipped back to the extents
of the data. If you enter a high Near number, areas closer to the grid will be clipped back to the
input data extents while retaining the interpolated areas over large gaps. Alternatively, a high Far
number should remove the interpolated gridded areas over the large gaps along with any extreme
outlying data points back to the extents of the input grid.