Thank you George,
On 3-Apr-09, at 9:22 AM, George Silva wrote:
Hello Aurora,
In ArcGIS it's all different. In PostGIS you can use simple/complex
SQL queries to "calculate values" in a similar fashion of arcgis.
The simplest of them all would be, in your case:
ALTER TABLE table1 ADD COLUMN area_column double precision;
UPDATE table1 SET area_column = ST_AREA(the_geom);
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.
Pretty straight forward SQL statement.
Is this a matter of opening a Terminal session using psql monitor?
Is it possible through pgAdmin or QGIS?
Thanks.
I hope that helps
George
On Fri, Apr 3, 2009 at 12:55 PM, Aurora Geomatics <[email protected]
> wrote:
Hello PostGIS users,
I have just installed William Kyng's PostgeSQ/PostGIS packages for
Mac OS X.5
I have been playing with pgAdmin and QGIS with importing shapefiles
into PostGIS. Works dandy.
Now I am wondering how to solve Attribute Calculations.
Years of using ArcGIS and GRASS it is pretty straightforward on
those apps, and am stumped with PostGIS Attribute calculations..
For example, using a polygon feature;
Creating a new column, say AREA and filling with a calculation that
is Hectares.
Thanks!
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