Paul,
I would recommend that you use the Distance Calculator tool. With this tool you
can find the nearest object in one table to each object in another table.
You would need MapInfo 8.0 to be able to do this though.
If you don't have MapInfo 8.0, I have nmade a tool called NearestObject that
can be found on Directionsmag.com under Tools.
Both tools will give you a result table containing an id from both table and a
line showing the distance. The Distance Calculator also updates a column with
the distance.
HTH,
Peter Horsbøll Møller
GIS Developer, MTM
Geographical Information IT
COWI A/S
Odensevej 95
DK-5260 Odense S.
Denmark
Tel +45 6311 4900
Direct +45 6311 4908
Mob +45 5156 1045
Fax +45 6311 4949
E-mail [EMAIL PROTECTED]
http://www.cowi.dk/gis
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Spencer Simpson
Sent: Friday, April 28, 2006 2:51 PM
To: [EMAIL PROTECTED]; 'Paul Donnelly'
Cc: mapinfo-l@lists.directionsmag.com
Subject: RE: [MI-L] Updating column with number of objects nearest apolyline...
Line-based Voronoi polygons would be nice, wouldn't they?
There's a way to approximate them by generating intermediate points but I'm not
sure the cure isn't worse than the disease...
Spencer
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Lars I.
Nielsen (GisPro)
Sent: Thursday, April 27, 2006 4:48 PM
To: Paul Donnelly
Cc: mapinfo-l@lists.directionsmag.com
Subject: Re: [MI-L] Updating column with number of objects nearest apolyline...
Hi Poul,
Would a feasible way not be to explode your polylines to node point objects,
and generate voronoi polygons around these points ? Preserving some sort of
polyline ID for each polygon.
That way you could find the points closest to any node, and sum the counts
using the polyline ID as aggregator.
Unless your polyline are really weird, it ought to give you a reasonable
result, or at least one that only counts single incident points once.
Best regards / Med venlig hilsen
Lars I. Nielsen
GisPro
Paul Donnelly wrote:
Hello all!
Was wondering if anyone can help me out with a little problem I need
help in solving? Basically, I have two MapInfo tables - One table containing
polylines representing road networks, and a second table containing point
objects representing the locations of road accidents.
I need a method of calculating the sum of accidents per road link.
Previously I had buffered the polylines and then simply used the 'update
column' function to sum up the number of objects within the buffer. The problem
with this though was that where two polylines meet at a junction there was an
overlap with the buffers and so when an accident point falls in this overlap it
is double counted within both overlapping buffers. With small sections of road
networks I simply edited the buffers to remove the overlap and then used the
update column method. The problem now is that I have a lot of road newtork data
and if I were to go round and remove each overlap for each individual section
I'd still be here this time next year!
So, ideally I need a method of assigning accident points to a single
road link which is nearest. Then I need to update a column within the link
table to count the number of accidents assigned to each particular road
section. Any help solving this problem would much appreciated!
Thanks in advance,
Paul Donnelly
Email: [EMAIL PROTECTED] mailto:[EMAIL PROTECTED]
**
This message contains information which is confidential and may also be
privileged. It is for the exclusive use of the intended recipient(s). If you
are not the intended recipient(s) please note that any form of distribution,
copying or use of this communication or the information in it is strictly
prohibited and may be unlawful. If you have received this communication in
error please return it to the sender and then delete the email and destroy any
copies of it. Thank you.
Hyder cannot guarantee that this message or any attachment is
virus-free or has not been intercepted or changed.
Any opinions or other information in this message that do not relate to
the official business of the Company are neither given nor endorsed
by it.
**
___
MapInfo-L mailing list
MapInfo-L@lists.directionsmag.com
http://www.directionsmag.com/mailman/listinfo/mapinfo-l
___
MapInfo-L mailing list
MapInfo-L@lists.directionsmag.com
http://www.directionsmag.com/mailman/listinfo/mapinfo-l
