[Qgis-user] Buffer with qgis : wgs84/mercator world?

[Stéphane Henriod]

Hi

I assume there is a misundersanding. I guess Jo assumed that your data is
stored in a PostGIS database, which is why he advised to cast the
coordinates as GEOGRAPHY.

As you seem to be working with shapefiles, this actually doesn't concern
you.

I would project my data into pseudo-mercator (EPSG:3857) in order to have
meter-based coordinates. But I am not sure it will give you the most
accurate resutls (don't know how it distorts the surface).

How precise does your buffer need to be? If you work on such a small scale
(Berlin - Beijing). I would assume that you don't really care about small
distortions, do you?

Cheers

Stéphane

--
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-- Albert Einstein

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enough in itself. One thinks that one is going to make a journey, yet soon
it is the journey that makes or unmakes you." -- Nicolas Bouvier

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On Fri, May 10, 2013 at 12:06 PM, image <lcelati at latitude-geosystems.com>wrote:

> Hello,
>
> Thank you for your reply. But sorry i do not really understand. Could you
> make explicit please?
>
> What do you understand by 'geography'?
>
> I just make a new test with world mercator & wgs84 also and the result of
> the buffers are always big circle . So i suppose that the unity is
> radians/degrés...
>
> My raw linear shp is very long. It is a corridor from Berlin to Beijing.
> According to you, which coordinate system i should select in order to
> generate a buffer (20kms)?
>
> Thank you.
>
>
>
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