[postgis-users] Help with query

[mark balman]

Hi Regina

Many thanks to your prompt answer, the query works great now! In my query
the coordinates were in Plate Carree metres and I think I confused myself
with the transform function. Much appreciated, any news on the proposed
postgis book?

Cheers

Mark
On Tue, Mar 10, 2009 at 12:16 PM, Obe, Regina <robe.dnd at cityofboston.gov>wrote:

>  Mark,
>
> I'm a bit confused,  for your second query, are those points suppose to
> represent user input and in long lat?  They don't look like long lat.  If
> they are meant to be long lat, then your args are just backwards.
>
> The basic idea I think you want to do  is
>
> 1) Take user input which I presume is in 4326 and then transform it to
> Plate Carree to match your existing data?
> Note ST_GeomFromText doesn't transform anything it simply states this data
> is in long lat and then transform changes the coordinates to Plate Carree
>
> So should be
>
> ST_Intersects(pas_nat_iv_pnt.the_geom ,ST_Transform(ST_GeomFromText(userinput,4326),
> 32662) )
>
> Hope that helps,
> Regina
>
>  ------------------------------
> *From:* postgis-users-bounces at postgis.refractions.net [mailto:
> postgis-users-bounces at postgis.refractions.net] *On Behalf Of *mark balman
> *Sent:* Tuesday, March 10, 2009 7:04 AM
> *To:* postgis-users at postgis.refractions.net
> *Subject:* [postgis-users] Help with query
>
>   Hi all
>
> I am trying to create a query that returns the features intersected by a
> user defined area. I can do this with the following query which works fine
> and returns what I want:
>
> select areaname, country
> FROM pas_nat_iv_pnt
> where ST_Intersects(pas_nat_iv_pnt.the_geom ,
> ST_GeomFromText('POLYGON((-7726647.392661 408830.119563 ,
> -6918290.736304  408830.119563 , -6918290.736304  828801.112346 ,
> -7726647.392661  828801.112346 , -7726647.392661 408830.119563 ))' , 32662)
> )
>
> However, what I need to do is to have a user enter latitude and longitude
> values and then transform these into Plate Carree coordinates, I have tried
> the following query:
>
> select areaname, country
> FROM pas_nat_iv_pnt
> where  ST_Intersects(pas_nat_iv_pnt.the_geom ,
> transform(ST_GeomFromText('POLYGON((-7726647.392661 408830.119563 ,
> -6918290.736304  408830.119563 , -6918290.736304  828801.112346 ,
> -7726647.392661  828801.112346 , -7726647.392661 408830.119563 ))' ,
> 32662),4326))
>
> The query runs but returns no rows.. I would be most grateful if anyone
> could enlighten me on what is wrong and what I need to change.
>
> TIA
>
> Mark
>
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