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

Sat Nov 30 11:53:31 CET 2019

Streaming link now published (thanks to Arild Schanke), only live when 
transmission active.

Roger

On Fri, 29 Nov 2019, Roger Bivand wrote:

> 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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-- 
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
https://orcid.org/0000-0003-2392-6140
https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en