[postgis-users] st_dist, st_sphere, st_spheroid - overhead/efficiency question

[Paul Ramsey]

If you only have data in the east, how does a correct SD record, with
a correct SD zip code, correct SD city name, and correct SD
coordinates show up? I think you need to take a coffee break.

P

On Thu, Jul 9, 2009 at 11:27 AM, Bo Coughlin<bo at rekindl.com> wrote:
> I have a foreign key 'buiding_id" to match on.  so I know its the same
> record. In addition all locations are in VA/WV/PA/DE/MD - - I must have
> transformed somehow during my process for I am an
> idiot. you think it would be better to get projections GDAL/OGR then create geom shape? or am i overdoing it? then I can run the distance thing ...again. - bo
>
>
> On Thu, Jul 9, 2009 at 2:23 PM, Paul Ramsey <pramsey at cleverelephant.ca>
> wrote:
>>
>> Are you referring to the first record? There is no ordering guarantee
>> in database tables. The first record in your file could be the
>> 12,000th in the database. The coordinates of that south dakota record
>> do look to be in south dakota. Seems a good sign to me.
>>
>> On Thu, Jul 9, 2009 at 11:20 AM, Bo Coughlin<bo at rekindl.com> wrote:
>> > right. but the location (in raw original) is:
>> > 1442 E FORT AVE  BALTIMORE MD 21230  39.269318 -76.594162
>> > where it is now:
>> > 308th Aveu  Gettysburg, SD 57442POINT(-100.000971435723
>> > 45.0003533555503)
>> >
>> > that's a bad thing...
>> >
>> >
>> > On Thu, Jul 9, 2009 at 2:06 PM, Paul Ramsey <pramsey at cleverelephant.ca>
>> > wrote:
>> >>
>> >> The coordinates you pasted in are valid points in the continental
>> >> USA...
>> >>
>> >> select st_srid(the_geom), st_astext(the_geom) from market_locations
>> >> limit
>> >> 1;
>> >> 4326    POINT(-77.1042756692815 38.995397678429)
>> >>
>> >> select st_srid(the_geom), st_astext(the_geom) from customer_locations
>> >> limit 1;
>> >> 4326    POINT(-100.000971435723 45.0003533555503)
>> >>
>> >> P
>> >>
>> >> On Thu, Jul 9, 2009 at 10:46 AM, Bo Coughlin<bo at rekindl.com> wrote:
>> >> > Hmmm....I just looked again at the points - they no longer match the
>> >> > original lat/lon coordinates, could I have somehow altered these via
>> >> > reprojecting them?
>> >> > Bo Coughlin
>> >> > bo at rekindl.com
>> >> > 704.414.0805
>> >> >
>> >> >
>> >> > On Thu, Jul 9, 2009 at 1:38 PM, Bo Coughlin <bo at rekindl.com> wrote:
>> >> >>
>> >> >> Tried - got nothing returned...little scary. - bo
>> >> >>
>> >> >> Bo Coughlin
>> >> >> bo at rekindl.com
>> >> >> 704.414.0805
>> >> >>
>> >> >>
>> >> >> On Thu, Jul 9, 2009 at 1:16 PM, Paul Ramsey
>> >> >> <pramsey at cleverelephant.ca>
>> >> >> wrote:
>> >> >>>
>> >> >>> Try this:
>> >> >>>
>> >> >>> --
>> >> >>> -- ST_DWithin_Sphere(lonlat-point, lonlat-point, radius-in-meters)
>> >> >>> returns boolean
>> >> >>> --
>> >> >>> -- Meters/Degree @ 60N: select 1/distance_sphere('POINT(0
>> >> >>> 60)','POINT(1 60)') = 1.79866403673916e-05
>> >> >>> --
>> >> >>> CREATE OR REPLACE FUNCTION ST_DWithin_Sphere(geometry, geometry,
>> >> >>> float8)
>> >> >>>        RETURNS boolean
>> >> >>>        AS 'SELECT $1 && ST_Expand($2,$3 * 1.79866403673916e-05) AND
>> >> >>> $2 && ST_Expand($1,$3 * 1.79866403673916e-05) AND
>> >> >>> ST_Distance_Sphere($1, $2) < $3'
>> >> >>>        LANGUAGE 'SQL' IMMUTABLE;
>> >> >>>
>> >> >>>
>> >> >>> SELECT m.id AS mid,
>> >> >>> m.building_i AS mb_id,
>> >> >>> c.id AS cid, c.building_i AS cb_id,
>> >> >>> m.streetaddr AS m_address,
>> >> >>> m.city AS m_city,
>> >> >>> m.state AS m_state,
>> >> >>> m.zip AS m_zip,
>> >> >>> m.zip4 AS m_zip4,
>> >> >>> round(CAST(
>> >> >>> ST_Distance_Sphere(m.the_geom, c.the_geom)
>> >> >>> AS numeric), 2) AS dist_meters
>> >> >>> FROM market_locations m, customer_locations c
>> >> >>> WHERE st_dwithin_sphere(m.the_geom, c.the_geom, 2414.016)
>> >> >>> _______________________________________________
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>> >> >
>> >> >
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