Thanks to all who responded.
Sum follows:
1) After you draw the first boundary, you can use the node snap ('S'
key to
turn on and off) to trace the common boundary line when drawing the next
polygon.
Hint: If you want to trace over a big piece of boundary (especially if it's
complicated), click the first point with snap on, hold down CTRL and click
further down the line. The points in between will be automatically traced.
If you've already drawn the polys and you want to correct them, select the
worst of the two adjoining polys, click the Node Edit button, and drag the
nodes over the good poly so they overlap. Then select Objects>Set Target.
Select the good poly and pick Objects>Erase. That will "cut" your bad poly
to exactly match the good one.
2) Mapinfo has no topology program within it. I am aware that recently
a
topological add-on has been released by mapinfo. Its around $2000 AUD. I
purchased a product called CartaLinx from the IDRISI mob @ Clark Uni for
around
$500 USD. I recall that they have a fully functional demo version on their
www
site. This demo may be enough to do your small job. I wouldn't advise buying
it
except if you plan using it for small jobs. When I loaded one of my datasets
into it, it took "hours" to do a job that ESRIs Data Automation Kit (around
$2000 AUD) took less than a minute to do. I ended up buying DAK as because
cartalinx didn't work on larger datasets. Beware though, DAK is an old DOS
program souped up to work in Windows. It lacks some of the windows
functionality
we've come to be used to, but if you're really only wanting to CLEAN & BUILD
topology, its a real winner.
3) There are a number of ways that you can create polygons so that you
do not
have this problem.
Method one is to have snap switched on if you are heads up digitising
existing polygons. To set snap tolerance Options / Preferences / Map
Window. This is a bit laborious if you have more than a few polygons to
create.
The next method is to copy the line nodes from the layer with the existing
polygon boundaries on to your new layer. To do this, ensure the layer with
the polygons or boundary lines to copy, is set to editable. Select a polygon
or polyline, select reshape button, then use shift click or alt click to
select the nodes you require. Hit Ctrl C (copy) then go to layer control
make your new layer editable. Hit Ctrl V (paste). Continue to do this until
you have created your new schools boundary based on the original table
polygons.
Method three; If you are creating your school boundaries from scratch you
can create the first polygon then each additional is purposely created to
overlap the first polygon. Then you use Objects / Set Target / Erase or
Split.
You will probably find that you will need to use a combination of all three
of the above to achieve the result you want.
Thanks to all. I am still working on it to figure out the "best" way to
deal with the issue.
Fran Peck
Peoria Unified School District
6330 W Thunderbird Rd
Glendale, AZ 85306
Voice: 623-486-6099
Fax: 623-486-6111
Email: [EMAIL PROTECTED]
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