On 5/23/2014 9:58 AM, Gerry Creager - NOAA Affiliate wrote:
I'll try this after putting out a few new fires! mylat and mylon are WKT?
SELECT poi.label, ST_Distance(geom, 'POINT(-74.0 42.0)'::geometry) AS dist
FROM poi
ORDER BY dist ASC LIMIT 4;
You might also need to deal with SRID if you have them defined for your
poi table. Then you might need:
'SRID=4326;POINT(-74.0 42.0)'::geometry
or you can do something like:
st_setsrid(st_makepoint(-74.0, 42.0), 4326)
-Steve
Thanks!
gerry
On Fri, May 23, 2014 at 8:54 AM, Stephen Woodbridge
<[email protected] <mailto:[email protected]>> wrote:
SELECT poi.label, ST_Distance(MakePoint(lon, lat), MakePoint(mylon,
mylat)) AS dist
FROM poi
ORDER BY dist ASC LIMIT 4;
-- or --
SELECT poi.label, ST_Distance(geom, MakePoint(mylon, mylat)) AS dist
FROM poi
ORDER BY dist ASC LIMIT 4;
where mylon, and mylat are you arbitray point locations.
-Steve
On 5/23/2014 9:46 AM, Gerry Creager - NOAA Affiliate wrote:
The inherent problem is that the point will be arbitrarily
specified. I
need to find the 4 points in the table 'sites' (it has label,
geom, and
lat, lon columns) closest to an arbitrary point given a lat/lon
coordinate pair.
Or, am I making this harder than I think I am?
Thanks!
gerry
On Fri, May 23, 2014 at 5:49 AM, Micha Silver <[email protected]
<mailto:[email protected]>
<mailto:[email protected] <mailto:[email protected]>>> wrote:
Use ORDER BY and LIMIT 4 to get the nearest 4 points:
Assuming your point table is called poi, and it has a
'geom' column,
and a 'label' column, and "lon' and 'lat' give the
coordinates of
the starting location, then
SELECT poi.label, ST_Distance(poi.geom, MakePoint(lon,
lat)) AS dist
FROM poi
ORDER BY dist ASC LIMIT 4;
On 22-May-14 11:47 PM, Gerry Creager - NOAA Affiliate wrote:
I need to query a rather smallish database and return 4
points
closest to a lat/lon (or lon/lat, if you prefer)
statement. I've
been off-line from PostGIS and my skills are worse than
rusty
right now...
Thanks
Gerry
--
Gerry Creager
NSSL/CIMMS
405.325.6371 <tel:405.325.6371> <tel:405.325.6371
<tel:405.325.6371>>
++++++++++++++++++++++
“Big whorls have little whorls,
That feed on their velocity;
And little whorls have lesser whorls,
And so on to viscosity.”
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405.325.6371 <tel:405.325.6371>
++++++++++++++++++++++
“Big whorls have little whorls,
That feed on their velocity;
And little whorls have lesser whorls,
And so on to viscosity.”
Lewis Fry Richardson (1881-1953)
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NSSL/CIMMS
405.325.6371
++++++++++++++++++++++
“Big whorls have little whorls,
That feed on their velocity;
And little whorls have lesser whorls,
And so on to viscosity.”
Lewis Fry Richardson (1881-1953)
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