The "problem" I submitted to the list was that when I was trying to position
exactly a MIG grid during its creation as a thematic map by adding to the
data 2 points representing the bounds I wanted, the resulting MIG would
contain one more row and column than necessary.

It "works as designed", simply it is poorly designed for my purpose. My
understanding of the way MI generates its MIG is that it takes the Xmin and
the Ymax of the point set as the upper left corner of the grid, and it
builds the grid from that point with the given cell width until all the
points are covered. If (Xmax - Xmin) and (Ymax - Ymin) are multiple of the
cell width, the point (Xmax, Ymin) becomes the upper left corner of the last
cell and not the lower right corner as I expected, and that explains why
there is then an "extra" column to the right and row to the bottom.

Vertical Mapper does not allow for exact positioning of the grid; it simply
sets the grid position as a multiple of the cell width. Of course, if you
define your cell map from the start with the proper coordinates to match
that requirement, you will have a good positioning of the WM grid relative
to your cell map.

Exact positioning without any constraint on data points or coordinates can
be found in Grid Analyser; that MI add-on can generate (version 4 at
www.terris.sk) MIG files with exact characteristics specified in a requester
and perfectly respected (xmin, xmax, ymin, ymax, cell width)

Thanks all who have pointed without necessarily knowing it towards the
"solution".

Jacques Paris
e-mail  [EMAIL PROTECTED]
MapBasic-MapInfo support  http://www.paris-pc-gis.com




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