[Qgis-user] HELP! Search Query Builder has limited operators

[badaveil]

PROBLEM SOLVED

The mistake which I found out as I stumble along GIS is that under
QGIS (which may be taken for granted by proficient users) tab files
can be viewed but cannot be edited (at that time, I happened to be
using a tab file) whereas shp files can be viewed as well as edited. I
right clicked that tab layer, saved it as a shp file and after
selecting that pencil icon found it editable. GREAT!

Next, to test calculation of area, I created a new column "test" using
new column icon,
then ticked update existing file and selected "test",
then under fields selected "test",
then under operators selected "area",
then selected ok
QGIS ran and out came the area as queried.

Thank you very much again for your help. Much appreciated.


On 08/02/2010, Marco Hugentobler <marco at hugis.net> wrote:
> You need to make the layer editable in order to use the calculator. Click on
> the pencil icon. After calculation, click on it again to save the changes to
> disk (or to discard).
>
> Regards,
> Marco
>
> Am Montag, 8. Februar 2010 15.10:45 schrieb badaveil:
>> Dr. Thank you again for a fast reply.
>>
>> I open a map, then open the attribute table, yes, I see the field
>> calculator, however, only the first 4 icons on the left until the
>> magnifine
>> glass are active, the rest including the field calculator are not active.
>> How do I activate it? So close but yet so far.
>>
>> Abbas
>>
>> On 8 February 2010 16:17, Marco Hugentobler <marco at hugis.net> wrote:
>> > Hi Abbas
>> >
>> > Use the field calculator (calculator button in the attribute table).
>> > There you
>> > have an area button and you may create a field with the feature area
>> > with
>> > it
>> > (or use arithmetic expression that contain the feature area).
>> >
>> > Regards,
>> > Marco
>> >
>> > Am Montag, 8. Februar 2010 09.10:58 schrieb badaveil:
>> > > I want to calculate the areas of specific plots of land (polygon). In
>> > > Mapinfo, the Search Query Builder has an "area" operator to help to do
>> > > this. However in QGIS, this basic function is missing and I am lost.
>> > > Please advice. Thanks
>> > >
>> > > Abbas
>> >
>> > --
>> > Dr. Marco Hugentobler
>> > HUGIS - GIS programming and consulting
>> > Webereistrasse 66
>> > CH-8134 Adliswil
>> > marco at hugis.net
>> > http://homepage.hispeed.ch/hugis
>> > Technical Advisor QGIS Project Steering Committee
>>
>
> --
> Dr. Marco Hugentobler
> HUGIS - GIS programming and consulting
> Webereistrasse 66
> CH-8134 Adliswil
> marco at hugis.net
> http://homepage.hispeed.ch/hugis
> Technical Advisor QGIS Project Steering Committee
>


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