[R-sig-Geo] sp/rgdal workflows with PROJ >= 6 and GDAL >= 3

Fri Nov 29 18:56:26 CET 2019

Thanks, we use the local, institutional interface which provides the quality we delivered at the 2014 Geostat summer school. The link will be posted on https://rsbivand.github.io/ECS530_h19/streaming_ecs530_h19.html when available (delayed because I've been off work). We'll just have to use Monday's classes to check that things are working, feedback info in the link above.

Roger

--
Roger Bivand
Norwegian School of Economics
Helleveien 30, 5045 Bergen, Norway
Roger.Bivand using nhh.no

________________________________________
Fra: Lorenzo Busetto <lbusett using gmail.com>
Sendt: fredag 29. november 2019 18.30
Til: Roger Bivand
Kopi: r-sig-geo using r-project.org
Emne: Re: [R-sig-Geo] sp/rgdal workflows with PROJ >= 6 and GDAL >= 3

Dear Roger,

    I'd be very interested in participating to the stream talk. Is it confirmed?

Concerning testing the connection, I'd be happy to do it but I do not know how much I will be available online in the coming days. You can drop me a mail/DM on twitter, and if I am available I'll gladly help.

Concerning technology, Zoom usually works quite well (https://zoom.us/<https://zoom.us/ent?zcid=3172>)

   regards,

Lorenzo

On Sat, 23 Nov 2019 at 13:04, Roger Bivand <Roger.Bivand using nhh.no<mailto:Roger.Bivand using nhh.no>> wrote:
A description of the status now with regard to a prototype resolution is
online at:

https://rsbivand.github.io/ECS530_h19/ECS530_III.html

I'm planning to stream a talk about this at 09:15-11:00 CET on Tuesday 3
December. I need a volunteer to test the streaming link in advance during
next week. I'm unsure which technology to use for remote participants to
provide feedback.

Contributions/comments welcome!

Roger

On Fri, 15 Nov 2019, Roger Bivand wrote:

> The development version of rgdal on R-Forge is now at rev 894, and is now
> ready for trying out with PROJ6/GDAL3 workflows, and workflows that may
> migrate within 6 months to modern CRS representations. The motivating RFC is
> also updated to cover coordinate operations, the use of prepared
> (pre-searched) coordinate operations, and should be read carefully by anyone
> using rgdal::spTransform(). Note further that rgdal::project() will not be
> adapted for PROJ6, and is effectively deprecated.
>
> I'll be running reverse dependency checks, and may be bugging package
> maintainers. I would really prefer that mainainers of packages using
> spTransform() checked themselves and joined this thread or the associated
> twitter thread: https://twitter.com/RogerBivand/status/1194586193108914177
>
> Be ready for modern PROJ and GDAL, they are already being deployed across
> open source geospatial software, like GRASS, QGIS, pyproj, spatialite etc.
>
> Waiting, hopefully not in vain, for contributions.
>
> Roger
>
> On Wed, 13 Nov 2019, Roger Bivand wrote:
>
>>  And this link explains the CDN proposal for grid distribution:
>>
>>  https://www.spatialys.com/en/crowdfunding/
>>
>>  Roger
>>
>>  On Wed, 13 Nov 2019, Roger Bivand wrote:
>>
>>>   Because PROJ >= 6 and GDAL >= 3 change the way that PROJ strings
>>>   (representations of coordinate reference systems) are handled, steps are
>>>   being taken to find ways to adapt sp/rgdal workflows. A current proposal
>>>   is to store the WKT2_2018 string as a comment to CRS objects as defined
>>>   in
>>>   the sp package.
>>>
>>>   A draft development-in-progress version of rgdal is available at
>>>   https://r-forge.r-project.org/R/?group_id=884, and for sp at
>>>   https://github.com/rsbivand/sp (this version of sp requires rgdal >=
>>>   1.5-1). This adds the WKT comments to CRS objects on reading vector and
>>>   raster data sources, and uses WKT comments if found when writing vector
>>>   and raster objects (or at least does as far as I've checked, possibly
>>>   fragile).
>>>
>>>   An RFC with tersely worked cases for using CRS object comments to carry
>>>   WKT strings but maintaining full backward compatibility is online at
>>>   http://rgdal.r-forge.r-project.org/articles/PROJ6_GDAL3.html.
>>>
>>>   If you have other ideas or concerns about trying to use this mechanism
>>>   for
>>>   sp CRS objects, please contribute at your earliest convenience.
>>>
>>>   http://rgdal.r-forge.r-project.org/reference/list_coordOps.html shows
>>>   the
>>>   beginning of the next step, to query transformation operations to find
>>>   viable coordinate operation pipelines.
>>>
>>>   I'm assuming that the previous behaviour (transform without considering
>>>   accuracy with whatever is to hand) is not viable going forward, and that
>>>   we will need two steps: list coordinate operations between source and
>>>   target CRS (using the WKT comments as better specifications than the
>>>   PROJ
>>>   strings), possibly intervene manually to install missing grids, then
>>>   undertake the coordinate operation.
>>>
>>>   The fallback may be simply to choose the least inaccurate available
>>>   coordinate operation, but this should be a fallback. This means that all
>>>   uses of spTransform() will require intervention.
>>>
>>>   Is this OK (it is tiresome but modernises workflows once), or is it not
>>>   OK
>>>   (no user intervention is crucial)?
>>>
>>>   These behaviours may be set in an option, so that package maintainers
>>>   and
>>>   users may delay modernisation, but all are undoubtedly served by rapid
>>>   adaptation (GRASS 7.8.1 released yesterday, libspatialite, pyproj, QGIS
>>>   development versions all state that they list candidate coordinate
>>>   operations).
>>>
>>>   We cannot ship all the grids, they are very bulky, and probably nobody
>>>   needs sub-metre accuracy world-wide. Work in PROJ is starting to create
>>>   a
>>>   content delivery network for trusted download and mechanisms for
>>>   registering downloaded grids on user platforms. We would for example not
>>>   want Windows users of rgdal and sf to have to download the same grid
>>>   twice.
>>>
>>>   Comments welcome here and at
>>>   https://github.com/r-spatial/discuss/issues/28 or
>>>   https://github.com/r-spatial/sf/issues/1187
>>>
>>>   Roger
>>>
>>>
>>
>>
>
>

--
Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; e-mail: Roger.Bivand using nhh.no<mailto:Roger.Bivand using nhh.no>
https://orcid.org/0000-0003-2392-6140
https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en

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