[postgis-users] -- Still having trouble retrieving properties 100 meters around a point --

[Bill Thoen]

On Tue, Sep 19, 2006 at 09:23:52PM -0700, Rafael Orta wrote:
>   The following statement does not work, not sure why
>    
>   update smarter.vow_properties set geom = makePoint (longitude, latitude);

I'm new to PostGIS too, but I'll take a stab at this anyway. I think you need
to specify the SRID when creating your geometry e.g.:

update smarter.vow_properties 
  set geom = SetSRID(makePoint (longitude,latitude),4326);

I think this will work even though your table's SRID is a projected one.
However, it might be better to use a NAD27 geographic coordinate system
SRID if your lat/long coordinates are really NAD27 (as suggested by your
choice of SRID for your table, 32011).

With an SRID of 32011, the units you are working with are US survey feet.
Also, I'm pretty sure you can't use Lat/Long coordinates with an SRID of
32011. That says to interpret the coordnates -074.905868 39.940252 as US
Survey Feet coordinates. I'm guessing, but I think you could use something
like this to convert points as lat/long to points as NJ state plane:


Transform(SetSRID(MakePoint(-074.905868 39.940252),4326),32011)

but I'm unfamiliar with Expand() and Distance(), so I'm out of guesses on
how to find all points 100ft from a particular point.

- Bill Thoen