[R-sig-Geo] Pre-GDAL 2: rgdal changes - from all according to their means

Wed Jun 3 10:12:57 CEST 2015

On Wed, 3 Jun 2015 at 17:14 Roger Bivand <Roger.Bivand at nhh.no> wrote:

> On Tue, 2 Jun 2015, chris english wrote:
>
> > Roger,
> >
> > I second Michael Sumner's excitement. I built a POSTGist SFCGAL stack
> based
> > on GDAL 2.0.0beta, anticipating that I could seamlessly integrate with R
> > and was disappointed that I couldn't use  2.0.0.beta  because at the
> point
> > only sp-1.1-1 was supported.
>
> Chris,
>
> Excitement doesn't help. GDAL 2 is only an advance over GDAL 1 in that it
> makes the code base easier to maintain because only the GDAL driver
> manager is supported, and vector drivers have been folded into the same
> model. Beyond that, we have continuing feature creep (e.g. use of
> Integer64 to hold IDs that notionally should be strings (no arithmetic)
> and which always lose leading zeros, and others. The key challenge
> (threat) to GDAL is the very limited number of core developers, followed
> by the same danger affecting many of GDAL's external dependencies.
>
> General comment: Could someone who knows how to do it please set up a
> searchable scribble sheet to which ordered examples, open issues, ideas,
> etc. could be contributed? This thread is now the prime location, but
> probably will become unwieldy.
>
>
What about MoPad?
https://etherpad.mozilla.org/8bU6hpr0YY

I set up a repo in github too but that might not be of interest since we
need pull-requests, forks etc.

https://github.com/mdsumner/rgdal_scribblesheet

Happy to help with any of this in whatever way people prefer.

Cheers, Mike.

> You will never be able to switch easily between rgdal installed against
> GDAL 1 and rgdal installed against GDAL 2. Any possibilities are only
> available to those installing GDAL from source, then rgdal from source, as
> GDAL 2 overwrites GDAL 1 (same name for gdal-config, same app names) if
> --prefix= is the same. If --prefix= is different between 1 and 2 when
> installing GDAL, and you take care with LD path names and use of ldconfig,
> you can pass these different locations of GDAL 1 and GDAL 2 through when
> installing rgdal. Then you'd also have to remember to install rgdal for
> GDAL 1 in say one R library folder, for GDAL 2 in a different library
> folder, and add the appropriate one to .libPaths(). It would be messy.
>
> Performance-wise, there should be no user-impacting difference between
> GDAL 1 and 2, or between rgdal opening for GDAL 1 or 2, and rgdal (<=
> 0.9-3), which blocks GDAL 2.
>
> The task now is to locate possible differences in behaviour between rgdal
> 0.9-3 with GDAL 1, and rgdal 1.0-2 with either GDAL 1 or 2. If there are
> 1|2 differences, are they because of changes in GDAL, or because rgdal was
> making inappropriate assumptions about GDAL?
>
> So far, we really don't know the Integer64 field type in GDAL 2 vectors is
> going to play out - as of now rgdal 1.0-2 truncates to integer. We don't
> know how the changes in the driver manager for vector dsn and layers
> affect layer and dsn overwriting (I'm seeing very odd OGRErr numbers in
> GDAL 2, and apparently different behaviour for some drivers). Writing
> MapInfo File TAB files looks broken (maybe a dsn creation option needs
> setting, when it wasn't needed before), etc.
>
> Some of this can be fixed by nasty kludges in rgdal, some should be fixed
> in GDAL 2, some are real misunderstandings. I don't have the time to try
> to make an rgdal Windows binary built against Windows GDAL 2 by
> cross-compiling for trying things out under Windows without user
> compilation. The transition will take time, but anyone who can install
> GDAL and rgdal from source, and who is interested and/or needs rgdal to
> work predictably, is welcome to run some standard procedures with rgdal
> 0.9-3 and GDAL 1, storing a text version of key results; install rgdal
> 1.0-2 (or later) and GDAL 1 (or later checked out from R-Forge and living
> under pkg/:
>
> #cd rgdal
> R CMD build pkg
> R CMD check rgdal_1.0-2.tar.gz
> # maybe --install-args='--configure.args=...'
> R CMD INSTALL rgdal_1.0-2.tar.gz
> # maybe --configure.args=...
>
> rerun the procedure and compare the results to see whether changes in
> rgdal have led to changes in the results, the re-install rgdal 1.0-2 with
> GDAL 2, rerun the procedure and compare the results, and compare those for
> GDAL 1 and GDAL 2.
>
> In particular, we need confirmation that the database access drivers work
> across these shifts.
>
> Roger
>
> >
> > I have a couple of future projects that are going to fundamentally depend
> > on GDAL and I hope to be able to address them from within R.  As an R
> > beginner I'm happy I have in my notes on how to point to my /opt/gdal(
> > please excuse if generalizing between an installed /opt/gdal(2.0,0.beta
> and
> > /usr/local/gdal(earlier.build)  build, but many people perhaps have not
> > been making a diary of R success(es).
> >
> > In the simplest case it could be a reminder to us beginners how we might
> > load a library(rgdal("in this case 2.0.0.beta vs our normal
> > library(rgdal)).  Well we are beginners, but we still want out stuff to
> > work and we want to contribute to a successful and comprehensive 2.2.0
> > release. So we'll run our particular research examples through 2.0.0 and
> > report results, if we know how to load one vs. another library.
> >
> > If intermediate or expert, different examples would be deployed.
> >
> > I apologize in advance if these issues  or methods have already been
> > addressed at SVN and I failed to notice them.  If that is the case I will
> > dig further, and please ignore me.
> >
> > I think GDAL and rgdal are intrinsically important tools to this
> community
> > and everyone wants them to work; please just tell us, by general example,
> > how we might be best of service.
> >
> > I hope the foregoing is comprehensible. My thoughts, and looking forward
> to
> > to contributing in a useful fashion to this important package (as a
> > beginner).
> >
> > Cheers,
> >
> > Chris
> >
> >
> > The second beta of GDAL 2 is now available, and as of revision 535 on
> >> R-Forge, the legacy rgdal package passes R CMD check with either GDAL
> >> 1.11.2 (or earlier) or GDAL 2.0.0 beta 2.
> >>
> >> One or two issues are known (Integer64 in vector fields and FIDs not
> >> supported in R; gdalDrivers() reports both raster and vector drivers;
> the
> >> MapInfo File TAB driver doesn't work for writing, ...), but others
> remain
> >> to be discovered.
> >>
> >> For those who need rgdal in production, and can install the 2.0.0 beta,
> it
> >> would be a really good use of time to identify issues now, rather than
> when
> >> GDAL 2 starts to become the standard, stable release. Anyone else
> needing
> >> an itch to scratch is also, of course, welcome to contribute.
> >>
> >> The rgdal package will continue to condition on GDAL 1 or 2, so
> hopefully
> >> those users who do not need to move to GDAL 2 will not be affected.
> >> However, it is worth noting that GDAL is maintained by very, very, few
> >> volunteers (even plural is questionable here), and when they feel that
> >> backporting fixed from GDAL 2 to GDAL 1 is taking time from more
> important
> >> things, you will be stranded with EOL software.
> >>
> >> So please consider taking the time to contribute to the idenfication of
> >> issues in the development version of rgdal built against GDAL 2 and/or
> 1,
> >> available for anonymous SVN checkout at:
> >>
> >> svn checkout svn://scm.r-forge.r-project.org/svnroot/rgdal/trunk
> >>
> >> Enjoy!
> >>
> >> Roger
> >>
> >> --
> >> Roger Bivand
> >> Department of Economics, Norwegian School of Economics,
> >> Helleveien 30, N-5045 Bergen, Norway.
> >> voice: +47 55 95 93 55; fax +47 55 95 91 00
> >> e-mail: Roger.Bivand at nhh.no
> >>
> >> _______________________________________________
> >> R-sig-Geo mailing list
> >> R-sig-Geo at r-project.org
> >> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >>
> >
>
> --
> Roger Bivand
> Department of Economics, Norwegian School of Economics,
> Helleveien 30, N-5045 Bergen, Norway.
> voice: +47 55 95 93 55; fax +47 55 95 91 00
> e-mail: Roger.Bivand at nhh.no
>
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