[prev in list] [next in list] [prev in thread] [next in thread] 

List:       postgis-users
Subject:    Re: [postgis-users] ST_DWithin with radius 0.000001
From:       nguyen liem <liemnguyendl () gmail ! com>
Date:       2010-05-25 14:33:06
Message-ID: AANLkTiligdp21ZZCHiKqpbqzneAlnJQXK0wdidB0RExa () mail ! gmail ! com
[Download RAW message or body]

[Attachment #2 (multipart/alternative)]


Hi Charles

Thanks for your answer, i can understand a little, i will try to research
more.
One more time, i would like to say thank you with you and Nicklas.

Cheers

On Tue, May 25, 2010 at 6:47 PM, Charles Galpin <cgalpin@lhsw.com> wrote:

>
> On May 25, 2010, at 5:43 AM, nguyen liem wrote:
>
> > One more question, if i would like to use ST_DWithin in projection WGS84
> and the radius is in 1 meter, how to do that?
>
> As someone else said it depends on the latitude you are dealing with, but
> you take the circumference of the earth at your location and divide by 360
> to get one degree. So at the equator one degree is roughly 69 miles or
> 111km.  So 0.00001 is 1m at the equator (but is .8m in NJ for example).
>
> hth,
> charles
>
> _______________________________________________
> postgis-users mailing list
> postgis-users@postgis.refractions.net
> http://postgis.refractions.net/mailman/listinfo/postgis-users
>



-- 
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.nguyen@axonactive.net / liemnguyendl@gmail.com
Web Site          : http://axonactive.vn
Address           : 87 Thang Long Street,Gate 2 Ward 4,
                         Tan Binh District, HCM city, Vietnam.

[Attachment #5 (text/html)]

Hi Charles<br><br>Thanks for your answer, i can understand a little, i will try to \
research more.<br>One more time, i would like to say thank you with you and \
Nicklas.<br><br>Cheers<br><br><div class="gmail_quote">On Tue, May 25, 2010 at 6:47 \
PM, Charles Galpin <span dir="ltr">&lt;<a \
href="mailto:cgalpin@lhsw.com">cgalpin@lhsw.com</a>&gt;</span> wrote:<br> <blockquote \
class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, \
204, 204); padding-left: 1ex;"><div class="im"><br> On May 25, 2010, at 5:43 AM, \
nguyen liem wrote:<br> <br>
&gt; One more question, if i would like to use ST_DWithin in projection WGS84 and the \
radius is in 1 meter, how to do that?<br> <br>
</div>As someone else said it depends on the latitude you are dealing with, but you \
take the circumference of the earth at your location and divide by 360 to get one \
degree. So at the equator one degree is roughly 69 miles or 111km.   So 0.00001 is 1m \
at the equator (but is .8m in NJ for example).<br>

<br>
hth,<br>
<font color="#888888">charles<br>
</font><div><div></div><div class="h5"><br>
_______________________________________________<br>
postgis-users mailing list<br>
<a href="mailto:postgis-users@postgis.refractions.net">postgis-users@postgis.refractions.net</a><br>
 <a href="http://postgis.refractions.net/mailman/listinfo/postgis-users" \
target="_blank">http://postgis.refractions.net/mailman/listinfo/postgis-users</a><br> \
</div></div></blockquote></div><br><br clear="all"><br>-- <br>Liem \
Nguyen<br>Developer<br>Axon Active \
Corp.<br>----------------------------------------------------------------------------<br>Direct \
Line         : +84 38 948 4645<br> Fax                           : +84 38 811 \
3489<br>Mobile Phone   : +84 168 994 8897<br>Skype ID             : \
liemnguyendl2204<br>Email                      : <a \
href="mailto:liem.nguyen@axonactive.net">liem.nguyen@axonactive.net</a> / <a \
href="mailto:liemnguyendl@gmail.com">liemnguyendl@gmail.com</a><br> Web Site          \
: <a href="http://axonactive.vn">http://axonactive.vn</a><br>Address                : \
87 Thang Long Street,Gate 2 Ward 4,<br>                                       Tan \
Binh District, HCM city, Vietnam.<br><br>



_______________________________________________
postgis-users mailing list
postgis-users@postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-users


[prev in list] [next in list] [prev in thread] [next in thread]