Hello Aurora,<br><br>In ArcGIS it's all different. In PostGIS you can use simple/complex SQL queries to "calculate values" in a similar fashion of arcgis.<br><br>The simplest of them all would be, in your case:<br>
<br>ALTER TABLE table1 ADD COLUMN area_column double precision;<br>UPDATE table1 SET area_column = ST_AREA(the_geom);<br><br>You can in that SQL query divide, multiply, and do whatever you want with that result that will be written to the column area_column.<br>
<br>I hope that helps<br><br>George<br><br><div class="gmail_quote">On Fri, Apr 3, 2009 at 12:55 PM, Aurora Geomatics <span dir="ltr"><<a href="mailto:aurorageomatics@gmail.com">aurorageomatics@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hello PostGIS users,<br>
<br>
I have just installed William Kyng's PostgeSQ/PostGIS packages for Mac OS X.5<br>
<br>
I have been playing with pgAdmin and QGIS with importing shapefiles into PostGIS. Works dandy.<br>
<br>
Now I am wondering how to solve Attribute Calculations.<br>
<br>
Years of using ArcGIS and GRASS it is pretty straightforward on those apps, and am stumped with PostGIS Attribute calculations..<br>
<br>
For example, using a polygon feature;<br>
<br>
Creating a new column, say AREA and filling with a calculation that is Hectares.<br>
<br>
Thanks!<br>
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</blockquote></div><br>