[GRASS-user] Reproject a large number of maps + converting to GeoJSON files

Nikos Alexandris nik at nikosalexandris.net
Fri Jan 29 05:30:28 PST 2016


Panagiotis Mavrogiorgos a écrit :

> > > > > 2. How can I handle vertex densification in the second approach?

Nikos Alexandris wrote:

> > > > Reminds of a v.clean related processing. You mean "simplification"?
> > > > Not sure if there is an related OGR tool too.

> > > No, I am referring to this:
> > > https://grasswiki.osgeo.org/wiki/Map_Reprojection#Vector_data:_have_enough_vertices_in_your_vector_data

> > Reportedly, v.proj does this now (==grass 7) automatically. Then, use it
> > (?).

> Well obviously that's one way to go, but the original question was how to
> handle vertex densification when directly using GDAL/OGR.

Right!  I just scanned the web for relevant stuff, see below:

Here something interesting (?):

* https://grasswiki.osgeo.org/wiki/Vector_add_multiple_vertices

Perhaps there is a quick way to access the "right" tool in/via
GDAL/OGR's (Python) API, and script it?

I found a couple of interesting threads... 

* http://osgeo-org.1560.x6.nabble.com/GDAL-C-Api-create-new-line-segments-from-point-layer-td5195061.html
* http://gis.stackexchange.com/q/8144/5256
* http://gis.stackexchange.com/a/29579/5256 (PostGIS related)
* http://geoinformaticstutorial.blogspot.ch/2012/10/accessing-vertices-from-polygon-with.html
* https://pcjericks.github.io/py-gdalogr-cookbook/

Maybe Markus Metz could enlighten!

Cheers, Nikos


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