Steve,
I'm not sure what is happening with your data, but CLEAN does do an
OVERLAY_NODES as its first step. So, you are effectively doing
OVERLAY_NODES twice. My reply was accurate.
Derek Snyder
MapInfo Corporation
"Wallace, Steve"
<[EMAIL PROTECTED]
com> To
[EMAIL PROTECTED]
08/04/2004 03:22 cc
PM [EMAIL PROTECTED],
Neil Gibson
<[EMAIL PROTECTED]>
Subject
RE: MI-L Objects> Check regions,
and objects> clean problem
Derek,
In this case, I don't think your reply is accurate. I just took a
Florida-wide table that I know has been edited several times and ran
"Objects > Clean" on it with both Overlap and Gap removal turned on, and
the
Maximum Gap Area set at 0.01 square miles (6.5 acres). When I ran Clean,
TWO
objects disappeared.
After rolling back the changes, performing an Object > Overlay Nodes
command, and THEN running Clean, only ONE polygon disappeared. The latter
case being only half as unacceptable an outcome as the first.
While I don't know how the software is engineered, I do know how it
performs.
-- Steve
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Wednesday, August 04, 2004 02:59 PM
To: Wallace, Steve
Cc: [EMAIL PROTECTED]; Neil Gibson
Subject: RE: MI-L Objects> Check regions, and objects> clean problem
Steve,
In this case, I don't think your advice will do anything. The Clean
operation actually does an OVERLAY_NODES operation as part of the
processing. So doing this extra step will do nothing.
The Clean operation should be designed so that if one object is completely
within another, then the smaller object should survive the clean operation
and a hole should be punched into the larger object. There is a chance
that
something is going wrong with this, and the smaller object is not surviving
the process, which could eliminate the row. If there are 2 objects that
exactly overlap and cover excatly the same space, one will be eliminated in
the overlap elimination process. But, baring this, it is hard to say what
may be happening without further investigation.
Derek Snyder
MapInfo Corporation
Mail List:
[EMAIL PROTECTED]
From: on 08/04/2004 11:10 AM AST
To: Neil Gibson <[EMAIL PROTECTED]>,
[EMAIL PROTECTED]
cc:
Subject: RE: MI-L Objects> Check regions, and objects> clean problem
Here's a little trick that might help you with most of the errors.
1) Make layer editable
2) Select all objects
3) Set as target
4) Select all objects (again)
5) Execute OBJECT > OVERLAY_NODES from the menu
This has the effect of deleting any duplicate identical nodes in your
objects. Often times those overlaps are what cause the problem. Also, this
WILL NOT change actual shape of your objects, like clean may. If you have
many spatial errors in a polygon (self-intersecting lines, gaps, overlaps,
etc), even Overlay Nodes can cause a record to vanish, so inspect your
resulting data.
Hope this helps,
-- Steve
-----Original Message-----
From: Neil Gibson [mailto:[EMAIL PROTECTED]
Sent: Wednesday, August 04, 2004 10:52 AM
To: [EMAIL PROTECTED]
Subject: MI-L Objects> Check regions, and objects> clean problem
Hi. I am having a bit of trouble with MapInfo 7, build 26, and was
wondering
if any of you could help? When i run the objects> check regions, I get 322
overlays and gaps from 11525 rows. However, when I try objects> clean, it
wipes half of the rows off from the map. Is there any way of removing
these
overlays and gaps without ruining my map?
Cheers
Neil
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