>
> > From: Vivek Mehra <vmehr@ctp.com>
> > Date: Wed, 1 Apr 1998 10:06:50 -0500
>
> > Am just starting out with PostgreSQL and would like to learn more about
> > the spatial data handling ablilities of postgreSQL - in terms of using
> > R-tree indexes, user defined types, operators and functions.
> >
> > Would you be able to suggest where I could find some code and SQL to
> > look at to create these?
>
> Here's the setup for adding an operator '<@>' to give distance in
> statute miles between two points on the earth's surface. Coordinates
> are in degrees. Points are taken as (longitude, latitude) and not vice
> versa as longitude is closer to the intuitive idea of x-axis and
> latitude to y-axis.
>
> There's C source, Makefile for FreeBSD, and SQL for installing and
> testing the function.
>
> Let me know if anything looks fishy!
>
> A note on testing C extensions - it seems not enough to drop a function
> and re-create it - if I change a function, I have to stop and restart
> the backend for the new version to be seen. I guess it would be too
> messy to track which functions are added from a .so and do a dlclose
> when the last one is dropped.
I have renamed this to earthdistance, and have added it to the /contrib
directory.
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