On 08/07/2010 11:31 AM, herman palaquium wrote:
glad to see you again
as you know that my places at N-E of the year ( please type buol
indonesia on the google maps) I STAY THERE
i remember that you give me the answer before, but CAN YOU GIVE
FORMULA HOW TO CONVERT 1 SQ DEG. TO ...... HECTARE ..?
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.
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.
In QGIS:
* you can project a shapefile to another CRS by using the "Save As"
option, and select whatever export CRS you want.
* Rasters can be re-projected using the Raster Tools plugin, gdalwarp tool.
[1] http://www.spatialreference.org/ref/?search=indonesia
--
Micha
PLEASE STEP BY STEP FORMULA YOU TYPE IT, FOR I KNOW THE WAY OF FORMULA
FUNCTION
I HOPE GREATEST THAT KNOW FOR MY STUDY
SALAM HORMAT
HERMAN DARI INDONESIA
On 27 Jun 10, at 0:47, Nicklas Avén wrote:
Hallo
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.
/Nicklas
----- Ursprungsmeddelande -----
> On 06/26/2010 03:40 PM, herman palaquium wrote:
> >
> > AREA: 2.7e-05
> > KebunPoly: KebunAmran1
> > Luas: 0
> > PERIMETER: 0.024863
> > Panjang: 0
> >
> > please help the area and perimeter unit
> >
> The numbers above indicate area: 0.000027 square units.
> If, by mistake, you projection units is degrees, instead of meters,
then
> this would be 0.000027 square degrees. One sq deg ~= 110 km X 110
km, or
> about 12,000 sq km. So the above would translate to approximately
> 327,000 sq meters. Does that make more sense?
>
> Again, if your units are degrees, not meters, then the perimeter would
> be around 2,730,000 meters. (110 km/deg X 0.2483 )
>
>
> > my projection is meter
> >
> > where is the correct 2,4863 meter
> >
> > or 24,863 meter
> >
> > or 248,63 meter
> >
> > or 2486,3 meter
> >
> > or 24863 meter
> >
> > or any answer the correct
> >
> > and than
> >
> > where is the correct area answer ?
> > 0,27 ha
> > 2,7 ha
> > 27 ha
> > 270 ha
> > or any answer the correc
> >
> >
> > herman
> > indonesia
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> >
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> >
>
>
> --
> Micha Silver
> Arava Development Co. +972-52-3665918
> http://www.surfaces.co.il
>
>
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--
Micha Silver
Arava Development Co. +972-52-3665918
http://surfaces.co.il
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