My problem is not `sliver polygons' i am familiar with them. My problem is
that i can create a succesfull polygonal topology and `audit geometry' after
it is created and i will still have very very small gaps in my drawing, all
represented by a red `X' and red lines.
My data is not corrupt i guarantee that, i can recreate this scenario after
wblocking only the topology layers into a new drawing, thus ensuring a clean
drawing.
seems to be a bug to me.
"Marion Pietsch (Autodesk)" wrote in
message news:3BCAC633.C4B1D2EA@autodesk.com...
> All,
>
> just some comments on sliver polygons...
>
> A topology is a highly sensitive thing and you might complain about the
amount
> of time cleaning takes, but the cleaner a drawing is the more accurate is
your
> data. And isn't that what you're aiming for?
>
> 'Sliver polygons' is one of the most common (error) message when creating
> polygon topologies, but nobody seems to care about that warning, because
Map
> still creates the topology. I consider this a defect 😉 because
apparently the
> understanding is missing what that means and how to deal with it. Find
below
> some explanation and suggestions.
> Looking at the other GIS programs I know, they don't work a lot different
and
> require approximately the same amount of time for cleaning, if not more
> depending on the available cleaning tools. Not all programs will give you
the
> change to create a topology when slivers exist.
>
> What is a sliver polygon?
> Basically, a sliver polygon is a polygon with a very small area or with a
lot
> smaller area than its perimeter and often results from not proper
digitizing,
> vectorizing scanned data or similar data creation processes, or from
having
> duplicates (for instance having the same boundaries, which are supposed to
be
> identical, on different layers, but in fact they are not identical).
> Another very common sliver polygon is a street network consisting of
polygons,
> not lines.
>
> How to handle sliver polygons?
> You should always, ALWAYS remove sliver polygons before (re-)creating
topology,
> otherwise you might run into problems like the described ones (topology
might be
> complete, but is not longer correct and all what results from that).
> Doing overlays, thematics or statistics on the parcel numbers and areas or
other
> analysis you wouldn't want to have these 'non-existing' miniature parcels
> counted and listed anyway, would you?
>
> Use Map's Cleanup tools!
> Map's Cleanup functions will help you cleaning the drawing, and not only
when
> experiencing sliver polygons. Also other untidinesses can be resolved. In
any
> case I recommend to have a look at Map's on-line help for details on the
cleanup
> order and other important cleanup information before starting the cleaning
> process.
>
> A street network requires different treatment, because you don't want to
delete
> the streets. These streets are only considered sliver polygons, because
the area
> is a lot smaller than the perimeter. Here are some suggestions how to
handle
> them:
> - Split the drawing into severals (using the 'Boundary Break' command) and
> attach them to a current work session. Doing this will split the street
polygon
> at least into a few ones.
> - Another solution is to split the streets manually into several polygons
in the
> current drawing.
> - And, another option would be to use a grid that splits the polygon/s
> automatically along the grid lines.
> Depending on the drawing structure you can use again the Cleanup or the
Dissolve
> command to unit the separated street segments later on again, if needed.
>
> Marion Pietsch
> WW Support & Services
> Autodesk GIS Product Support
>
>
> mike hathaway wrote:
>
> > Jadranko, that is the EXACT problem i am having, i do not have those
> > specific errors in my log file but i do have many others. I will send a
> > copy of a file to Autodesk and see what they determine. This is a very
> > annoying and time consuming problem.
> >
> > "Jadranko Stjepanovic" wrote in message
> > news:86EFFDBEC3DF67530F95A387129DCC90@in.WebX.maYIadrTaRb...
> > > Mark,
> > >
> > > I had similar problem in some of my projects, and it is not described
in
> > > TS33603 as you suggested. TS33603 describes the problem which arises
when
> > > you are saving back topology objects to the source drawings. I
experienced
> > > described problem while working on a single dwg file, without any
source
> > > dwgs attached.
> > > Map successfully created topology, but placed several red marks in few
> > > spots.
> > > I audited topology immediately after it was created, and Map reported
it
> > as
> > > "incorrect and complete". If I remembered it correctly, marks were
placed
> > > over the long and narrow polygons (rivers for example), and I used
> > geodetic
> > > coordinates with seven decimal places left of decimal point.
> > > I'm not quit sure, but I think Map created acadmap.log file with these
> > > problems reported:
> > >
> > > AutoCAD Map Warning : 2003 - Sliver polygon.
> > > AutoCAD Map Error : 2005 - Some links could be lost.
> > >
> > > Mike, do you have something like that in your acadmap.log ?
> > >
> > > This problem caused me a lot of trouble, so I'm very interested in
solving
> > > it.
> > >
> > > Thanks in advance,
> > > Jadranko
> > >
> > >
> > > Mark Christian wrote in message
> > > news:B1EF4F1C1314C8674480C2FD5F29B068@in.WebX.maYIadrTaRb...
> > > > Hello Mike,
> > > >
> > > > The message you are receiving is an audit message that is displayed
in
> > Map
> > > > 2000 and Map 2000i.
> > > >
> > > > Please see http://support.autodesk.com/getDoc.asp?id=TS33603
> > > >
> > > > The message is rather confusing and should probably read "the source
and
> > > > current topologies are inconsistent".
> > > >
> > > > Regards,
> > > >
> > > > Mark Christian
> > > > GIS Product Support
> > > > Autodesk, Inc.
> > > > "mike hathaway" wrote in message
> > > > news:63A09C17D8CDB47312572BC88A606F98@in.WebX.maYIadrTaRb...
> > > > > Using Map 4, Ldd2i, WIN 98, all Service packs installed
> > > > >
> > > > > I am creating a polygonal topology of thousands of parcels of land
in
> > > > > indiviual section drawings.
> > > > >
> > > > > The problem i am having is this. After I create a successful
> > polygonal
> > > > > topology and the Audit Geometry it says topology is incorrect and
> > > complete
> > > > > and highlights the various gaps with Red lines and Xs.
> > > > >
> > > > > How can this be? I spend about an hour or so in each section
cleaning
> > > up
> > > > > all the gaps during the creation of the topology. Now once i
finish
> > it
> > > > and
> > > > > it is successful i still have small gaps.
> > > > >
> > > > > WHY? How can the topology be successful yet still have gaps.
THIS
> > > SEEMS
> > > > > LIKE A BUG TO ME and has caused us many $$$ in files turned back
from
> > > our
> > > > > client due to incorrect topology that was successfully created,
yet
> > > > > incorrect!
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
>
![Autodesk Design & Make Report](https://forums.autodesk.com/t5/image/serverpage/image-id/1350519iCB55845EBFC43016/image-size/large?v=v2&px=999" "Autodesk Design & Make Report")
