[postgis-users] RE: Spatial query for the Nearest location given alat and long?

[Milo van der Linden]

I agree.

In preparing my sample nearest function for this post, I assumed that
the points mentioned where in spatial_columns, hence making best use of
indices and all.
My advice would be to create a geometry column for this table and
convert the lat/lon columns to one spatial column. That's where postGIS
will be at it's best, not in storing doubles in two columns.

Rick Zoolker schreef:
> Looks like you got it.  FYI, ST_Point($longitude, $latitude) will work
> slightly faster than using the GeomFromText().  Also, as Regina
> mentioned, you won't be making use of any spatial indicies here, so
> the query will run slower than what would be possible.
>
> On 8/13/07, bdbeames <bdbeames at cc.usu.edu> wrote:
>   
>> Results
>>
>> Ok, I think it is working.
>>
>> Here what I got for future reference
>>
>> Given a $latitude and $longitude point I query table_1 to find the
>> closest/nearest location points.
>>
>> SELECT id, name,
>>    distance_sphere(GeomFromText('POINT('|| $longitude ||' '|| $latitude
>> ||')'),
>>    GeomFromText('POINT('|| table_1.longitude ||' '|| table_1.latitude
>> ||')')) as dist
>> FROM table_1
>> WHERE active = 't'
>> ORDER BY dist LIMIT 5;
>>
>> Thanks again for all the help
>> --
>> View this message in context: http://www.nabble.com/Spatial-query-for-the-Nearest-location-given-a-lat-and-long--tf4253824.html#a12133535
>> Sent from the PostGIS - User mailing list archive at Nabble.com.
>>
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>   


-- 


	

Milo van der Linden
skype: milovanderlinden <skype:milovanderlinden?add>
mlinden at zeelandnet.nl <mailto:mlinden at zeelandnet.nl>
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milo at 3dsite.nl <mailto:milo at 3dsite.nl>
http://www.3dsite.nl

	  	

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