[Qgis-user] Area Calculation in Field Calculation

[Harish]

Yes I was a problem of version. I was using 1.8 on a system where 1.7.4 was
also installed and probably plugin did not update itself with installation
of 1.8. When I installed 1.8 on a machine which doesn't have any version of
QGIS, it showed correct window.

Thanks
Harish
On Sun, Jul 8, 2012 at 1:49 PM, Jeremy Hill <hije14 at gmail.com> wrote:

>    Harish,
>  As my screen capture shows, I am able to select the Layer or Project or
> Ellipsoid CRS. I am able to do it on a “Line” “Point” and “Polygon”
> Shapefile (.shp) file. I’m running QGIS 1.8 Lisboa. Maybe check and make
> sure that you have the most up-to-date version. Apart from that I’m not
> sure what else to tell you. Hopefully someone else can help.
>  Jeremy
>
>  *From:* Harish <harry.om2000 at gmail.com>
> *Sent:* Sunday, July 08, 2012 12:59 AM
> *To:* Jeremy Hill <hije14 at gmail.com>
> *Cc:* qgis-user at lists.osgeo.org
> *Subject:* Re: [Qgis-user] Area Calculation in Field Calculation
>
> Thanks! point one is solved but for point two, export/add geometry tool
> returns the window as attached, there is no option for choosing CRS for
> area calculation.
>
> Regards
>
> On Fri, Jul 6, 2012 at 10:14 PM, Jeremy Hill <hije14 at gmail.com> wrote:
>
>>
>>
>> ------------------------------
>>
>> Message: 4
>> Date: Fri, 6 Jul 2012 15:16:09 +0530
>> From: Harish <harry.om2000 at gmail.com>
>> To: Qgis-user at lists.osgeo.org
>> Subject: [Qgis-user] Area calculation in field calculator
>> Message-ID:
>> <CAKCjEX9Vt_**0jvEEiHSMOVGMGRR3wMb-**0e6BHiZHmrqnB_4Z_=Q at mail.**gmail.com<Q at mail.gmail.com>
>> >
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> 1-
>> I converted projection 4326 to 32643(UTM zone 43N) to get are calculation.
>> I used geometry operator as $area with creating a new field of decimal
>> (real) type with width 10 and 2 precision. I tried with different widths
>> and precisions, every time there are 7-8 digits after decimal, like,
>> 2361773.81506348
>> 2895003.41503906
>> 1384160.6237793
>> 10020411.4874268
>>
>> ANSWER1----- You need to uncheck the "Toggle Editing" and "save" your
>> layer and then it will be displayed with the proper width and precision
>> that you set it to.
>>
>>
>> 2
>> Further I read in new functionality list of QGIS1.8 that area/length etc.
>> may be calculated by using project (if in metric units) CRS in QGIS 1.8,
>> without changing original CRS of layer if it is in Geographic coordinates.
>> Is this feature available in 1.8?
>>
>> ANSWER2---  It does give you the option that when you use "Export/Add
>> Geometry Column" that it gives you the option to Calculate using Layer CRS,
>> Project CRS, or Ellipsoid. You can save to a new layer or update the
>> current one which your using. I have not experimented with this in
>> different projections to verify the accurate data or the area/length but
>> the "plugin" does work.
>>
>> Regards
>>
>> OS-Windows7, QGIS 1.8 stand alone
>>
>
>



-- 
Harish Kumar Solanki, Assistant Professor
National Institute of Rural Development (NIRD),
Ministry of Rural Development, Government of India
Jaipur, Rajasthan, India- Pin-302006

Email- hksolanki at nird.gov.in, harry.om2000 at gmail.com,
Tele-Fax-0141-2209905, Mo.- 09214446732, 09414291732
Website-  http://www.nird.org.in,
http://watershed.rajasthan.gov.in/<http://www.nird.org.in>
LinkedIn: www.linkedIn.com/in/hksolanki
<http://www.nird.org.in>
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