Sorry Jacques.,
I would stick with my original comments that if you are getting slivers
from combining adjacent polygons in the same table, then there are
definitately problems in the data that need fixing. These errors are a
result of common boundaries not matching exactly. Building a coverage from
linework as ARC does avoids this issue as the same lines are used for
adjacent polys. There are products for MapInfo that do the same thing
(eg. GIS ToolBox from ERSIS, that contains the program that Melanie was
describing is but one).
That does not solve the problem that she has, a coverage that has slivers.
In general, I agree with your comments about grids, and have been using
that technique for 6 years now. This has been mainly because I've been
waiting for a raster module that integrates with MapInfo. I thought that
VM was the answer, and while its good, until it has some of the analytical
tools that you can use for databases (e.g. look-up tables, categorisation
using referential tables, analysis using sql queries between joined
tables), I will continue to just use it to display the results I have got
from the gridcell type approach.
This brings up two points
1. a tool to get rid of slivers from a table
2. raster analysis tools
1. I have written a tool that buffers a polygon and cuts it bak using the
surrounding polygons, thereby getting rid of those slivers, but it only
works for a selected polygon. I would be happy to give this code to anyone
willing to develop a program that first created the bounding polygon (the
current extents of the existing coverage), and the progressed through the
table buffering and cutting, and then trimmed the edges off using the
original bounding polygon.
2. And to Jacques, I have some MapBasic code to polygonise a regular grid
that is pretty neat (not as neat as the equivalent in VM). If you would
like to complement your grid cell program, then I will provide the code to
you to incorporate.
Robert Crossley
Trinity Software
10 Trinity Street
Parramatta Park
CAIRNS 4870
email: [EMAIL PROTECTED]
web: www.trinitysoftware.com.au
ftp: ftp.trinitysoftware.com.au
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