Allan,
MapInfo/MapBasic 8.0 have a new feature that can do this calcualtion.
Nearest statement
Find the object in a table that is closest to a particular object. The result is a 2 point Polyline object representing the closest distance.
Syntax
Nearest [N | ALL] >From { Table fromtable | Variable fromvar }
To totable Into intotable
[Type { Spherical | Cartesian }]
[Ignore [Contains] [Min min_value] [Max max_value] Units unitname]
[Data clause]
This is the statement behind the improved DistanceCalculator in v8.0
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 Krisciunas, Allan
Sent: Wednesday, February 22, 2006 10:44 PM
To: mapinfo-l@lists.directionsmag.com
Subject: [MI-L] Nearest
How does MapInfo determine nearest map features? I have 2 road network layers, almost identical but offset slightly. I'm trying to write a query to fill a column in road layer A with the distance to the nearest equivalent arc in layer B. How?
Or an even simpler question: how can I find the distance between nearest points in the same layer?
I've looked at the SQL query function : SphericalDistance( num_x , num_y , num_x2 , num_y2 , str ) -- I assume that could be the lat/long of the nearest point to the one whose column I am trying to insert the distance value. But other than physically double-clicking the nearest neighbour, and hand-copying its lat/long values into a 2nd column, I can't determine how to get MapInfo to automatically generate these values.
I realise that this is a type of network analysis; so does that mean that I have to $$buy$$ another MapInfo product so I can do this work??
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