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

[Nikos Alexandris]

Panagiotis Mavrogiorgos a écrit:
 
> Which is the prefered method of reprojecting a large number of maps and
> converting them to e.g. GeoJSON files?

If only a (re-)projection/conversion task, you may rely on gdal/ogr utilities.
 
> I think that there are two options:
> 
> 1. (According to the wiki
> <https://grasswiki.osgeo.org/wiki/Map_Reprojection>), you should create a
> new location with the export projection you want to export, import the maps
> using {v,r}.proj and then export the maps (e.g. using v.out.ogr/r.out.gdal.

Perhaps it is possible to skip the import part. Using, instead, [rv].external ...?
 
> 2. Export the maps directly using v.out.ogr/r.out.gdal and then reproject
> them using GDAL/OGR.
> 
> So,
> 
> 1. So are there any significant differences between the two methods? AFAIK
> the underlying algorithms should be the same.
> 
> The first method seems to have higher disk space requirements, while the
> second one seems to be easier to implement.
> 
> 2. How can I handle vertex densification in the second approach?

Reminds of a v.clean related processing. You mean "simplification"?

Not sure if there is an related OGR tool too.

Nikos
 
> 3. Are there any other caveats that I need to be aware of?