[GRASS5] Database linking question

Frank Warmerdam warmerdam at pobox.com
Wed Jan 3 00:15:47 EST 2001

"Eric G . Miller" wrote:
> My understanding is (in the U.S. at least) file formats can't be
> patented, but certainly ESRI (or any other vendor) isn't going to freely
> share the data structures of their cash-cows.  My understanding of the
> Arc/Info Workspace is something like a segmented ISAM database with
> "arcs" being spatially sorted and attributes being keyed in by id's on
> the given type of spatial object (with a separate "table" for each
> type).  There's got to be some kind of hierarchical tree to move between
> levels of spatial "objects" (regions->polys->arcs->nodes->vertices).


Note that the ESRI binary vector coverage format has been thoroughly 
reverse engineered.  The analysis can be found at:


Legend has it that ESRI started court action against ER Mapper many years
ago over their having reverse engineered the binary coverage format, but
they I haven't heard of their taking any action against anyone in recent

Best regards,

I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerda
and watch the world go round - Rush    | Geospatial Programmer for Rent

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