The polygon you are testing against, is it very complex?
How long time does it take?
did you analyse the table after adding the index?
/Nicklas
2010-05-25 nguyen liem wrote:
Hi Nicklas
>
>sr for the mistake ... field but it was not improve the perofrmance for
>ST_intersect
>
>Cheers
>
>>
On Tue, May 25, 2010 at 3:53 PM, nguyen liem <liemnguye...@gmail.com> wrote:
>Hi Nicklas
>
>my dataset about 100.000 rows and after run my query i get about 15.000 rows.
>I has created index for "geom" field but it was improve the perofrmance for
>ST_intersect
>
>I used SRID 4326, but I don't know how to convert from degree to meter.
>
>Cheers
>
>>
>
>
>
On Tue, May 25, 2010 at 3:43 PM, Nicklas Avén
<nicklas.a...@jordogskog.no> wrote:
>>
>
>
>
Ok
>
>The distance of 0.00001 degree in east west direction will vary depending on
>how far from the equator you are.
>
>How many points is there in your dataset?
>
>Do you see if the index is used?
>
>/Nicklas>
>
>
>
>2010-05-25 nguyen liem wrote:
>
>Hi Nicklas
>>
>>Actually the points can be outside the polygon and returning true but it can
>>be tolerance about 1 meters outside.
>>I'm using SRID: 4326. I would like to know 0.00001 with the projection 4326
>>is equal 1 meter or not ?
>>
>>I used ST_Intersects (geom, geometry); but it's really slow, I don't know why.
>>I also used ST_Dwithin (geom, geometry, 0) and the result is empty, i
>>couldn't found any neighbour.
>>
>>Cheers
>>
>>>>
>
>
>
On Tue, May 25, 2010 at 3:22 PM, Nicklas Avén
<nicklas.a...@jordogskog.no> wrote:
>>>>
Hallo
>>
>>What you are doing with ST_Dwithin is to check if your geom and geometry have
>>parts closer to (or exactly) 0.00001 mapunits from eachother. If you are
>>using a meter based SRID then you are checking if they are within 0.00001
>>meters from eachother. So actually in this case your points can be just
>>outside the polygon and returning true. If you want to use st_dwithin you
>>should use 0 instead of 0.00001 . But I don't think that is any faster than
>>ST_Intersects. The important thing in both cases is to have working spatial
>>indexes.
>>
>>put an index on geom column in my_neighbour table and analyze the table.
>>
>>Create index idx_mn_geom
>>on my_neighbour
>>using gist(geom);
>>analyse my_neighbour;
>>
>>Then try:>>
>>SELECT id, geom
>>FROM my_neighbour
>>WHERE ST_Intersects (geom, geometry);
>>
>>I guess that is the best solution.
>>
>>Hope that helps
>>
>>Nicklas>>
>>
>>2010-05-25 nguyen liem wrote:
>>
>>Hi all
>>>
>>>At the first time i used ST_Contains but it take a long time, so I used
>>>ST_Dwithin to improve the performance for the query statement but i don't
>>>know it is correct or not.
>>>I would like to know my points are within in polygon or not:
>>>
>>>SELECT id, geom
>>>FROM my_neighbour
>>>WHERE ST_Dwithin (geom, geometry, 0.00001)
>>>
>>>geometry: is a polygon(input parameter).
>>>0.00001: I means the radius of geometry is 1 meters, is it right?
>>>
>>>
>>>Cheers.
>>>
>>>--
>>>Liem Nguyen
>>>Developer
>>>Axon Active Corp.
>>>----------------------------------------------------------------------------
>>>Direct Line : +84 38 948 4645
>>>Fax : +84 38 811 3489
>>>Mobile Phone : +84 168 994 8897
>>>Skype ID : liemnguyendl2204
>>>Email : liem.ngu...@axonactive.net / liemnguye...@gmail.com
>>>Web Site : axonactive.vn>>
>>>Address : 87 Thang Long Street,Gate 2 Ward 4,
>>> Tan Binh District, HCM city, Vietnam.
>>>
>>>
>>_______________________________________________
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>>
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>>
>>>
>>
>>
>>--
>>Liem Nguyen
>>Developer
>>Axon Active Corp.
>>----------------------------------------------------------------------------
>>Direct Line : +84 38 948 4645
>>Fax : +84 38 811 3489
>>Mobile Phone : +84 168 994 8897
>>Skype ID : liemnguyendl2204
>>Email : liem.ngu...@axonactive.net / liemnguye...@gmail.com
>>
>Web Site : axonactive.vn
>>Address : 87 Thang Long Street,Gate 2 Ward 4,
>> Tan Binh District, HCM city, Vietnam.
>>
>>
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>>
>
>
>--
>Liem Nguyen
>Developer
>Axon Active Corp.
>----------------------------------------------------------------------------
>Direct Line : +84 38 948 4645
>Fax : +84 38 811 3489
>Mobile Phone : +84 168 994 8897
>Skype ID : liemnguyendl2204
>Email : liem.ngu...@axonactive.net / liemnguye...@gmail.com
>Web Site : axonactive.vn>
>
>
>Address : 87 Thang Long Street,Gate 2 Ward 4,
> Tan Binh District, HCM city, Vietnam.
>
>
>
>
>--
>Liem Nguyen
>Developer
>Axon Active Corp.
>----------------------------------------------------------------------------
>Direct Line : +84 38 948 4645
>Fax : +84 38 811 3489
>Mobile Phone : +84 168 994 8897
>Skype ID : liemnguyendl2204
>Email : liem.ngu...@axonactive.net / liemnguye...@gmail.com
>Web Site : axonactive.vn
>Address : 87 Thang Long Street,Gate 2 Ward 4,
> Tan Binh District, HCM city, Vietnam.
>
>
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