In mapbasic, how to determine if a table contains spatial objects
Nicholas G Lawrence
Hello all,
I am scripting a MabBasic tool to do an audit of several thousand mapinfo tables.
One thing I am trying to capture is the min and max extents of the spatial objects in the table
But, some tables have no spatial objects at all and thus the command TableInfo(table_id,TAB_INFO_MINX) returns an error.
This is at a step where I have already confirmed that the table is a native mapinfo table, is mappable, I have captured the coordsys clause and the table does have a non-zero number of rows.
Is there a mapbasic command that can determine if a table contains spatial objects?
Nick Lawrence
Senior Spatial Science Officer | Geospatial Technologies
Engineering & Technology | Transport and Main Roads
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Regards,
Peter Horsbøll Møller
And you might want to just count the records with or without objects which might be faster.
Select Count(*) "nrecs" from parcels
where obj
into _q noselect hide
Now _q.nrecs will tell you the number of records with spatial objects
A quick test with a table holding around 100,000 records shows a slight improvement in performance.
1.8 – 2.4 secs for the grouped compared to 2.2 – 3.2 secs for the non-grouped query
Not really that big a difference
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Subject: [MI-L] Re: In mapbasic, how to determine if a table contains spatial objects
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