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<DIV dir=ltr align=left><SPAN class=875304713-09022010><FONT color=#0000ff
size=2 face=Arial>Thanks Ibo but I forgot to mention I need one transform that
works with all locations, but that it does not need to be accurate so +/- 10%
would be acceptable. I need to catagorise some areas by size so for
example 100-1000 m2, 1000-10000 m2 for visual purposes.</FONT></SPAN></DIV>
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<DIV dir=ltr align=left><FONT size=2 face=Tahoma><B>From:</B>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <B>On Behalf Of
</B>ibrahim saricicek<BR><B>Sent:</B> 09 February 2010 15:47<BR><B>To:</B>
PostGIS Users Discussion<BR><B>Subject:</B> Re: [postgis-users] Polygon area in
meters<BR></FONT><BR></DIV>
<DIV></DIV>Hi;<BR><BR>one method...<BR>ST_Distance_Spheroid(point_x, point_y,
'SPHEROID["WGS 84",6378137,298.257223563]');<BR><BR>the other method create a
new geometry (the_geom_epsg) column ansd find the exaxt EPSG code for your
region (i prefer 2321 for middle Turkiye ED50 /TM 33)<BR><BR>update table set
the_geom_epsg=st_transform(the_geom, epsg)<BR>then use
st_area..<BR><BR>Regards..<BR>IBO..<BR><BR>
<DIV class=gmail_quote>On Tue, Feb 9, 2010 at 3:40 PM, Kemal Bayram <SPAN
dir=ltr><<A href="mailto:kemal@cins.co.uk">kemal@cins.co.uk</A>></SPAN>
wrote:<BR>
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<DIV>
<DIV><FONT size=2 face=Arial><SPAN>Hi,</SPAN></FONT></DIV>
<DIV><FONT size=2 face=Arial><SPAN></SPAN></FONT> </DIV>
<DIV><FONT size=2 face=Arial><SPAN>I'm current working with data in long/lat
(wgs84) format and using st_distance_spheroid to calculate the length of my
linestrings in meters. I now need to calculate the area of my polygons
and am wondering what the easiest way of doing this would be?
</SPAN></FONT></DIV>
<DIV><FONT size=2 face=Arial><SPAN></SPAN></FONT> </DIV>
<DIV><FONT size=2 face=Arial><SPAN>I am thinking projecting the polygon with
an equal area projection and then using st_area on the result.
Anyone have any ideas on suitable projections/SRIDS?</SPAN></FONT></DIV>
<DIV><FONT size=2 face=Arial><SPAN></SPAN></FONT> </DIV>
<DIV><FONT size=2 face=Arial><SPAN>Regards</SPAN></FONT></DIV>
<DIV><FONT size=2 face=Arial><SPAN></SPAN></FONT> </DIV><FONT
color=#888888>
<DIV><FONT size=2
face=Arial><SPAN>Kemal</SPAN></FONT></DIV></FONT></DIV><BR>_______________________________________________<BR>postgis-users
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