<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML xmlns="http://www.w3.org/TR/REC-html40" xmlns:v =
"urn:schemas-microsoft-com:vml" xmlns:o =
"urn:schemas-microsoft-com:office:office" xmlns:w =
"urn:schemas-microsoft-com:office:word"><HEAD><TITLE>Message</TITLE>
<META http-equiv=Content-Type content="text/html; charset=us-ascii">
<META content="MSHTML 6.00.2800.1400" name=GENERATOR><!--[if !mso]>
<STYLE>v\:* {
BEHAVIOR: url(#default#VML)
}
o\:* {
BEHAVIOR: url(#default#VML)
}
w\:* {
BEHAVIOR: url(#default#VML)
}
.shape {
BEHAVIOR: url(#default#VML)
}
</STYLE>
<![endif]-->
<STYLE>@font-face {
font-family: Tahoma;
}
@page Section1 {size: 8.5in 11.0in; margin: 1.0in 1.25in 1.0in 1.25in; }
P.MsoNormal {
FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman"
}
LI.MsoNormal {
FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman"
}
DIV.MsoNormal {
FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman"
}
A:link {
COLOR: blue; TEXT-DECORATION: underline
}
SPAN.MsoHyperlink {
COLOR: blue; TEXT-DECORATION: underline
}
A:visited {
COLOR: purple; TEXT-DECORATION: underline
}
SPAN.MsoHyperlinkFollowed {
COLOR: purple; TEXT-DECORATION: underline
}
SPAN.EmailStyle17 {
COLOR: windowtext; FONT-FAMILY: Arial; mso-style-type: personal
}
SPAN.EmailStyle18 {
COLOR: navy; FONT-FAMILY: Arial; mso-style-type: personal
}
SPAN.EmailStyle19 {
COLOR: navy; FONT-FAMILY: Arial; mso-style-type: personal-reply
}
DIV.Section1 {
page: Section1
}
</STYLE>
</HEAD>
<BODY lang=EN-US vLink=purple link=blue>
<DIV><SPAN class=235221822-28092004><FONT face=Arial color=#0000ff size=2>not
possible...I have 300K spatial records...</FONT></SPAN></DIV>
<DIV><SPAN class=235221822-28092004></SPAN> </DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <B>On Behalf Of
</B>Craig Miller<BR><B>Sent:</B> Tuesday, September 28, 2004 4:18
PM<BR><B>To:</B> 'PostGIS Users Discussion'<BR><B>Subject:</B> RE:
[postgis-users] Computing area in km^2 from 4326
geometries<BR><BR></FONT></DIV>
<DIV class=Section1>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">One rather blunt way
would be to store your data in a projection that accurately maintains area and
is based in meters/kilometers.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">--Craig<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<DIV class=MsoNormal style="TEXT-ALIGN: center" align=center><FONT
face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt">
<HR tabIndex=-1 align=center width="100%" SIZE=2>
</SPAN></FONT></DIV>
<P class=MsoNormal><B><FONT face=Tahoma size=2><SPAN
style="FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT
face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Ethan
Alpert [mailto:ealpert@digitalglobe.com] <BR><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Tuesday, September 28, 2004 3:12
PM<BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> PostGIS Users
Discussion<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> RE:
[postgis-users] Computing area in km^2 from 4326
geometries</SPAN></FONT><o:p></o:p></P></DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<P class=MsoNormal><FONT face=Arial color=blue size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">I'm getting degrees^2
because my geometry is in lat/lon afaict.</SPAN></FONT><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial color=blue size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">-e</SPAN></FONT><o:p></o:p></P></DIV>
<BLOCKQUOTE style="MARGIN-TOP: 5pt; MARGIN-BOTTOM: 5pt; MARGIN-RIGHT: 0in">
<P class=MsoNormal style="MARGIN-BOTTOM: 12pt"><FONT face=Tahoma
size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">-----Original
Message-----<BR><B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <B><SPAN
style="FONT-WEIGHT: bold">On Behalf Of </SPAN></B>Craig Miller<BR><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Tuesday, September 28, 2004 4:07
PM<BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> 'PostGIS Users
Discussion'<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> RE:
[postgis-users] Computing area in km^2 from 4326
geometries</SPAN></FONT><o:p></o:p></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">If the area
function is returning square meters (depends on your projection) then just
divide the answer by 4046.896 to get
kilometers.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">All area functions
are squared by definition.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">--Craig<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<DIV class=MsoNormal style="TEXT-ALIGN: center" align=center><FONT
face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt">
<HR tabIndex=-1 align=center width="100%" SIZE=2>
</SPAN></FONT></DIV>
<P class=MsoNormal><B><FONT face=Tahoma size=2><SPAN
style="FONT-WEIGHT: bold; FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">From:</SPAN></FONT></B><FONT
face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> Ethan
Alpert [mailto:ealpert@digitalglobe.com] <BR><B><SPAN
style="FONT-WEIGHT: bold">Sent:</SPAN></B> Tuesday, September 28, 2004 2:57
PM<BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> PostGIS Users
Discussion<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B>
[postgis-users] Computing area in km^2 from 4326
geometries</SPAN></FONT><o:p></o:p></P></DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN
style="FONT-SIZE: 12pt"><o:p> </o:p></SPAN></FONT></P>
<DIV>
<P class=MsoNormal><FONT face=Arial color=blue size=2><SPAN lang=DE
style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">How does one
compute areas in km^2? I was thinking something like
area2d(transform(the_geom,<someEPSG>)). </SPAN></FONT><SPAN
lang=DE><o:p></o:p></SPAN></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial color=blue size=2><SPAN lang=DE
style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">How do others do
this?</SPAN></FONT><SPAN lang=DE><o:p></o:p></SPAN></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN lang=DE
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial color=blue size=2><SPAN lang=DE
style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">Thanks!</SPAN></FONT><SPAN
lang=DE><o:p></o:p></SPAN></P></DIV>
<DIV>
<P class=MsoNormal><FONT face="Times New Roman" size=3><SPAN lang=DE
style="FONT-SIZE: 12pt"> <o:p></o:p></SPAN></FONT></P></DIV>
<DIV>
<P class=MsoNormal><FONT face=Arial color=blue size=2><SPAN lang=DE
style="FONT-SIZE: 10pt; COLOR: blue; FONT-FAMILY: Arial">-e</SPAN></FONT><SPAN
lang=DE><o:p></o:p></SPAN></P></DIV></BLOCKQUOTE></DIV></BLOCKQUOTE></BODY></HTML>