[postgis-users] Nearest Neighbor question

[Gerry Creager - NOAA Affiliate]

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 <micha at arava.co.il> 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
> ++++++++++++++++++++++
>  “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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-- 
Gerry Creager
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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