From: | Bruno Wolff III <bruno(at)wolff(dot)to> |
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To: | Olivier Chaussavoine <olivier(dot)chaussavoine(at)gmail(dot)com> |
Cc: | DCorbit(at)connx(dot)com, pgsql-general(at)postgresql(dot)org, Uwe Schroeder <uwe(at)oss4u(dot)com> |
Subject: | Re: earthdistance |
Date: | 2013-08-24 19:35:42 |
Message-ID: | 20130824193542.GA23625@wolff.to |
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Lists: | pgsql-general |
On Tue, Aug 20, 2013 at 20:38:51 +0200,
Olivier Chaussavoine <olivier(dot)chaussavoine(at)gmail(dot)com> wrote:
>I also look at cube extension, but the built in type box - a couple of
>points - does not require any extension and has a GIST index. It can be
>used to represent a rectangle on the domain [-PI/2,+PI/2[*[-PI,PI[. If the
>extension was providing a function get_rect_from_cap() giving the smallest
>rectangle of this domain containing a spherical cap, this rectangle could
>be used as you pointed out to reduce the set of rows where the earth
>distance need to be computed to know if a point A belongs to the cap. The
>operator && (box overlaps box) could be used if the point A is converted to
>box(A,A). Do you think this function get_rect_from_cap() could be usefull?
Depending on how the sphere is represented, getting the minimum bounding
cube is pretty simple and it might not be worth writing a function for
this.
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