In looking at EPSG:26986 on <a href="http://spatialreference.org">spatialreference.org</a> (
<a href="http://spatialreference.org/ref/epsg/26986/">http://spatialreference.org/ref/epsg/26986/</a> ) it appears that the projection's native units are meters rather than feet. If you divide by 4046.85642 (number of square meters in an acre) your acreage numbers will come out much closer than they are at present but will still be a bit off.<br clear="all">
--<br>Nathan Gerber<br>
<br><br><div class="gmail_quote">On Mon, Jul 9, 2012 at 11:44 PM, Daniel Cole <span dir="ltr"><<a href="mailto:daniel@southernsolutionsms.com" target="_blank">daniel@southernsolutionsms.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
I am using the code below:<div><br></div><div><b>Select name, acreage, ST_Area(ST_Transform(geom, 26986))/43560 as acres from ss.fields</b></div><div><br></div><div>and getting these results.  </div><div><br></div><div><br>


</div><div><table style="font-size:13px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif"><tbody><tr><th style="background-color:rgb(230,230,204);font-size:smaller">name</th><th style="background-color:rgb(230,230,204);font-size:smaller">


acreage</th><th style="background-color:rgb(230,230,204);font-size:smaller">acres</th></tr><tr><td style="background-color:rgb(243,243,233);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap">


H 01</td><td style="background-color:rgb(243,243,233);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


15.79</div></td><td style="background-color:rgb(243,243,233);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


1.50398045317257</div></td></tr><tr><td style="background-color:rgb(230,230,204);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap">

H 02</td><td style="background-color:rgb(230,230,204);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


29.02</div></td><td style="background-color:rgb(230,230,204);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


2.76480120804097</div></td></tr><tr><td style="background-color:rgb(243,243,233);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap">

H 03</td><td style="background-color:rgb(243,243,233);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


31.95</div></td><td style="background-color:rgb(243,243,233);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


3.04337512685165</div></td></tr><tr><td style="background-color:rgb(230,230,204);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap">

H 04</td><td style="background-color:rgb(230,230,204);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


34.71</div></td><td style="background-color:rgb(230,230,204);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


3.30710750534269</div></td></tr><tr><td style="background-color:rgb(243,243,233);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap">

H 05</td><td style="background-color:rgb(243,243,233);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


111.6</div></td><td style="background-color:rgb(243,243,233);margin:4px;font-family:arial,tahoma,verdana,helvetica,sans-serif,serif;padding:0px;font-size:smaller;text-align:left;white-space:nowrap"><div style="text-align:right">


10.6322788992474</div></td></tr></tbody></table></div><div><br></div><div><br></div><div><br></div><div>I have another program where I am importing the acreage data from and I just wanted it to match up in postgis well in case I ever wanted to calculate it myself.  It seems that I am almost there, but I am a decimal off and I can't understand that.  </div>


<div><br></div><div>Also I am not very familiar with the 26986, but I used it because I saw it used for sqare feet somewhere else.  Should I be using anything else?  <br><br>Thanks,<br><br>DC<br>
</div>
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