I've discovered a method that may be good enough, to allow MapInfo TAB files
that were created as "version 100" to pass as valid "version 300" (current
as of MapInfo v7 ??).
I say "pass as valid version 300" TAB files, because of course if they were
created as v100 (1.00) the feature set for the contained vector data will be
of the same vintage.
The only current reason for doing this, as far as I know, is to allow
Manifold System Release 6.00 to read TAB files (TAB, ID, DAT, MAP) that were
created as MapInfo "v100" format.
There may be good reasons why the following procedure should NOT be
followed, but here it is anyway.
It seems it's all in the formatting of the TAB file.
A v100 TAB file is like this -
--------
!table
!version 100
FIELDS: 3
feat_code CHAR (12)
q_info CHAR (8)
ufi CHAR (10)
--------
A v300 TAB file is like this -
--------
!table
!version 300
!charset WindowsLatin1
Definition Table
Type NATIVE Charset "WindowsLatin1"
Fields 3
feat_code CHAR (12) ;
q_info CHAR (8) ;
ufi CHAR (10) ;
--------
(A simple utility to rewrite TAB files could be created).
(I think that long fieldnames - more than 10 characters - can be handled OK.
But there's still a question over truncation - I'm not yet sure HOW or even
IF it really occurs - see previous post).
I have successfully fooled Manifold System Release 6.00 into reading several
sets of Australian BMR (AGSO / Geoscience Australia) MapInfo tables, by
simply changing the TAB file in this way.
Checking imported data, onscreen display, and output in the same projection
for both GIS systems show that it's valid, for a few tables that I tried.
Manifold has obviously defined its TAB import on the "latest" format: v300.
It can also import MIF/MID files, and so long as these reflect the MapInfo
TAB format feature set accurately, that's probably the best exchange format.
Except that Manifold doesn't support all the points, fonts, line styles,
colours, and fills that are encoded into the MIF/MID files. In fact, most of
this decoration is totally lost (even the colours).
Ian Thomas
GeoSciSoft - Perth, Australia
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