Hi Mike,
If MapInfo Pro calculates the centroid, it's always inside the polygon(s).
It might use the MBR mid point as 1st choice, but it'll move it inside the
polygon if it has to. Try draw a "moon shaped" polygon to verify this.
But you can "work around" that by exporting your table to MIF, change the
"center" coordinates, and re-import. If a REGION in MIF has a centroid
(center clause), it'll import that without error-checking it. Which off
course will corrupt your data in some respects. Only if a "center" clause
is absent, will MI Pro calculate one for you during import.
You can use that to rectify your data. I.e.: export to MIF, remove all
"center" clauses, and re-import. That's should get the data back on track.
Best regards
Lars Nielsen
**********************************************************
Lars Nielsen [EMAIL PROTECTED]
Senior Programmer, MapXtreme iGIS Specialist
Kampsax/MapInfo, Odense http://www.mapinfo.dk
Authorized MapInfo Distributor in Denmark & Norway
Address: Rugaardsvej 55, DK-5000 Odense C
Telephone: +45 6313-5000 Facsimile +45 6313-5090
**********************************************************
C & K Townsend
<[EMAIL PROTECTED]> Til: Steve Wallace
<[EMAIL PROTECTED]>
Sendt af: cc: Mike Hankins
<[EMAIL PROTECTED]>,
[EMAIL PROTECTED]
[EMAIL PROTECTED]
onsmag.com Vedr.: Re: MI-L Centroids of
objects
30-03-01 09:02
Besvar venligst til C & K
Townsend
Mike
I'm a little inexperienced but I believe that Mapinfo creates a centroid
by using something called a minimum bounding rectangle(MBR). In this
scenario it is quite possible for Mapinfo to return a centroid position
outside of the polygon in question. I know of no way around this.
Regards
Craig Townsend
Guyra Shire Council
NSW AUSTRALIA
Steve Wallace wrote:
>
> Sounds like you have some spatial errors in this table. I've never seen a
> centroid outside an object. Even if you try and move a centroid outside
an
> object by hand, MapInfo will give you an error.
>
> Use MapCheck (for older MapInfo versions), or Objects > Check Regions (in
> newer) to see if there are any problems with these regions.
>
> To re-cast all the centroids in a table, you can make the layer editable,
> select all regions, convert all to polylines, then convert all back to
> regions.
>
> Steve Wallace
>
> ----- Original Message -----
> From: "Mike Hankins" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Thursday, March 29, 2001 12:01 PM
> Subject: MI-L Centroids of objects
>
> > Hello,
> > I ran into a problem while updating a column. The wrong
territory
> > value was being assigned to the object and I have figured it out that
the
> > centroid is outside of the polygon. Is there a way to check a file to
see
> > if the centroid of a object is outside of the polygon for that object?
I
> > will have over 50 tables with as many as 3000 polygons in each table.
Is
> > there a way to update the columns without using a centroid based
solution?
> >
> > Thanks to All,
> >
> > Mike Hankins
> > COUNTRY Insurance and Finacial Services
> >
> >
> >
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