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On 08/07/2010 11:31 AM, herman palaquium wrote:
<blockquote cite="mid:1F4FE48D-810D-47BA-8B50-FA0CACA7B607@gmail.com"
type="cite">
<div>glad to see you again</div>
<div><br>
</div>
<div>as you know that my places at N-E of the year ( please type buol
indonesia on the google maps) I STAY THERE</div>
<div><br>
</div>
<div>i remember that you give me the answer before, but CAN YOU GIVE
FORMULA HOW TO CONVERT 1 SQ DEG. TO ...... HECTARE ..?</div>
</blockquote>
You can *not* just convert degrees to hectares in a Lon/Lat projection.
The rough figures I sent last time were just an inaccurate estimate.
Afterall, as you move north or south towards the poles, the width of 1
degree changes in size.<br>
What you should do is re-project your data to some projected coordinate
reference system. Then units will then most likely be in meters, and
you can calculate areas very simply. I see [1] that Indonesia uses a
set of Transverse Mercator projections. You might chose the one
relevant to your area.<br>
<br>
In QGIS:<br>
* you can project a shapefile to another CRS by using the "Save As"
option, and select whatever export CRS you want.<br>
* Rasters can be re-projected using the Raster Tools plugin, gdalwarp
tool.<br>
<br>
[1] <a class="moz-txt-link-freetext" href="http://www.spatialreference.org/ref/?search=indonesia">http://www.spatialreference.org/ref/?search=indonesia</a><br>
<br>
-- <br>
Micha<br>
<br>
<blockquote cite="mid:1F4FE48D-810D-47BA-8B50-FA0CACA7B607@gmail.com"
type="cite">
<div><br>
</div>
<div>PLEASE STEP BY STEP FORMULA YOU TYPE IT, FOR I KNOW THE WAY OF
FORMULA FUNCTION</div>
<div><br>
</div>
<div>I HOPE GREATEST THAT KNOW FOR MY STUDY </div>
<div><br>
</div>
<div>SALAM HORMAT</div>
<div>HERMAN DARI INDONESIA</div>
<div><br>
</div>
<div>
<div>On 27 Jun 10, at 0:47, Nicklas Avén wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div>
<p>Hallo <br>
<br>
hmm, is this right Micha. Isn't the size of a sqare degree depending on
how far from equator it is. Since the vertical longitudes are
convergating to the poles 1 west-east degree is 0 at the pole and about
40000/360 km at the equator which makes the conversion difficult. <br>
<br>
/Nicklas <br>
----- Ursprungsmeddelande ----- <br>
> On 06/26/2010 03:40 PM, herman palaquium wrote: <br>
> > <br>
> > AREA: 2.7e-05 <br>
> > KebunPoly: KebunAmran1 <br>
> > Luas: 0 <br>
> > PERIMETER: 0.024863 <br>
> > Panjang: 0 <br>
> > <br>
> > please help the area and perimeter unit <br>
> > <br>
> The numbers above indicate area: 0.000027 square units. <br>
> If, by mistake, you projection units is degrees, instead of
meters, then <br>
> this would be 0.000027 square degrees. One sq deg ~= 110 km X 110
km, or <br>
> about 12,000 sq km. So the above would translate to approximately <br>
> 327,000 sq meters. Does that make more sense? <br>
> <br>
> Again, if your units are degrees, not meters, then the perimeter
would <br>
> be around 2,730,000 meters. (110 km/deg X 0.2483 ) <br>
> <br>
> <br>
> > my projection is meter <br>
> > <br>
> > where is the correct 2,4863 meter <br>
> > <br>
> > or 24,863 meter <br>
> > <br>
> > or 248,63 meter <br>
> > <br>
> > or 2486,3 meter <br>
> > <br>
> > or 24863 meter <br>
> > <br>
> > or any answer the correct <br>
> > <br>
> > and than <br>
> > <br>
> > where is the correct area answer ? <br>
> > 0,27 ha <br>
> > 2,7 ha <br>
> > 27 ha <br>
> > 270 ha <br>
> > or any answer the correc <br>
> > <br>
> > <br>
> > herman <br>
> > indonesia <br>
> > _______________________________________________ <br>
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> <br>
> <br>
> -- <br>
> Micha Silver <br>
> Arava Development Co. +972-52-3665918 <br>
> <a moz-do-not-send="true" href="http://www.surfaces.co.il">http://www.surfaces.co.il</a>
<br>
> <br>
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> <br>
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</p>
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<br>
<pre class="moz-signature" cols="72">--
Micha Silver
Arava Development Co. +972-52-3665918
<a class="moz-txt-link-freetext" href="http://surfaces.co.il">http://surfaces.co.il</a>
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