MessageIt is possible if you use the MITAB C++ source code directly
(setspatialfilter), while the C API (and the DLL) do not allow it.
Regards
Uffe
----- Original Message -----
From: Warren Vick, Europa Technologies Ltd.
To: 'Tim Smith' ; '<MapInfo-L'
Sent: Monday, June 05, 2006 12:17 PM
Subject: RE: [MI-L] How mapinfo loads map data
Hello Tim,
The ability to dynamically load only the parts of a map layer that are in a
current view is achieved through a spatial index. This avoids the need for
any map renderer to go through all features to test if they are needed for
the view. MapInfo uses a spatial indexing method known as R-Tree. Since I'm
not too familiar with MITAB, I don't know if it has the ability to use this
index to query features in a table based on a coordinate rectangle. It would
not surprise me if it didn't since I believe MITAB was originally written
for external (i.e. outside a MapInfo environment) read/write of TAB file
sets, and maybe not with a home-brew renderer in mind.
Regards,
Warren Vick
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