View source for VM Create Grid

<ol>
=Introduction=
This is an excellent way of visualising check files such as the _zpt_check.mif that is written by TUFLOW.  This check file is outputted after all elevation data and topography modifiers (breaklines, z zhapes etc) have been processed.  This method can also be applied to other data, such as survey data to create a DEM.

=Method=
<li>From the menu items select ''Vertical Mapper >> Create Grid >> Interpolation''.</li>
<li>Select an interpolation method, see the MapInfo documentation for more details.  For creating a DEM from a _zpt_check file I use ''Triangulation with smoothing''.</li>
[[File:VM grid interpolation1.png|frame|none|Select Method for Grid Interpolation]]
<li>Select the table and column for the data you want to grid.</li>
File:VM grid interpolation2.png|none|frame|Select Data to Interpolate]]
<li>Set the grid interpolation parameter, this depends on the method selected above, for triangulation of a zpt_check file, set the ''Maximum Triangle Side Length'' to be just less than your largest cell size (this ensures that you don't get triangulation across gaps in data).<li>
[[File:VM grid interpolation3.png|none|frame|Set Triangulation Options]]
<br>
Depending on the number of points the interpolation could take a few minutes.<br>
<li>Follow the prompts and set a cell size and name for the output grid.  If using triangulation I set a ''Linear Solution''.</li>
[[File:VM grid interpolation4.png|none|frame|Set Cell Size and Output Name]]
A grid should now be processed and displayed, to enable relief shading see this <u>[[VM_Grid_Manager#Relief_Shading | page]]</u>.
[[File:VM grid interp zpt chk.png|frame|none|Final DEM (of the _zpt_check.mif for TUFLOW tutorial module 1)]]