[postgis-devel] RFC: Remove mmin and mmax from GBOX

[Paul Ramsey]

Yeah, by removing the fourth dimension you're foreclosing on 4d
indexing to some extent, since gboxes are used to pass around full
extents of 4d objects.

On Wed, Jul 6, 2011 at 7:41 AM, Mark Cave-Ayland
<mark.cave-ayland at siriusit.co.uk> wrote:
> Hi all,
>
> Whilst trying to get rid of the following compile warning:
>
> gcc -O2 -Wall -Wmissing-prototypes -Wpointer-arith
> -Wdeclaration-after-statement -Wendif-labels -fno-strict-aliasing -fwrapv
> -fpic -I/home/pg90/rel/include  -I/usr/include/libxml2 -I../liblwgeom -I.
> -I. -I/home/pg90/rel/include/postgresql/server
> -I/home/pg90/rel/include/postgresql/internal -D_GNU_SOURCE   -c -o
> geography_estimate.o geography_estimate.c
> geography_estimate.c: In function ‘compute_geography_stats’:
> geography_estimate.c:1048: warning: ‘histobox.mmax’ may be used
> uninitialized in this function
> geography_estimate.c:1048: warning: ‘histobox.mmin’ may be used
> uninitialized in this function
> geography_estimate.c:1048: warning: ‘histobox.flags’ may be used
> uninitialized in this function
>
> it suddenly struck me that we are doing some strange and inconsistent things
> with the M value when building GBOXes. Looking closer at the logic, I've so
> far come to the conclusion that M is an attribute, not an extra dimension
> and so on this basis it has no spatial component and therefore should not be
> stored within GBOX.
>
> Therefore I'd like to propose the attached patch to remove M from GBOX
> entirely - thoughts?
>
>
> ATB,
>
> Mark.
>
> --
> Mark Cave-Ayland - Senior Technical Architect
> PostgreSQL - PostGIS
> Sirius Corporation plc - control through freedom
> http://www.siriusit.co.uk
> t: +44 870 608 0063
>
> Sirius Labs: http://www.siriusit.co.uk/labs
>
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