Andrea Aime schrieb:
> Jürgen Jacob ha scritto:
>> Dear all,
>>
>> is it possible to buffer Points into Polygons? I've a shapefile with 
>> point features and I want to create a buffer around them. How can I do 
>> this? The CRS is WGS84 and the buffer should be 50m. The resultung 
>> geometry objects will be polygon, or?
> 
> JTS provides a buffer operation, but that works only in cartesian space,
> it won't help you in your specific case.
> I see two practical solutions to your problem:
> - if the points are located in a limited area, reproject them to
>    a metric projection that has low deformation over the area
>    of interest (utm, lambert, whatever), do the buffers with JTS,
>    reproject the polygons you get back to WGS84.
>    This approach works with every kind of geometry
> - if the points are located in a large area, use GeodeticCalculator
>    to create the buffers manually. Set the starting point at one of
>    the point that needs buffering, and ask for the coordinates of
>    a point 50m away, with an azimut of 0. Then use an azimuth or
>    30, 60, 90 and so on, connect the resulting point, and there
>    you have the shell of the buffer polygon. Repeat for all points
>    and you're done.
> 
> Hope this helps
> Cheers
> Andrea

Thanks a lot!!

I'll check what will be the best solution for my application. How do I 
reproject geometries?

Cheers,
Jürgen



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