[OSGeoLive] Proj6 questions - draft

[Sebastiaan Couwenberg]

On 4/7/19 11:46 AM, Cameron Shorter wrote:
> Thanks Bas for this technical insight. This proj.h adoption table
> provides a useful insight adoption. What would be really useful is if we
> can collect expected implementation timelines. Do you know if anyone has
> been collecting such information?

Some projects track milestones (with a date) on GitHub, but those dates
are far from set in stone.

The release planning for PROJ itself does this, and generally sticks
close to the planned release dates, see:

 https://github.com/OSGeo/proj.4/milestones

> I feel there it would be useful to community from techies to the wider
> user community about:
> 
> What is proj6. What is all the fuss about.

The PROJ docs are quite good:

 https://proj4.org/

But as discussed on the proj list, not as actively maintained as the
codebase.

The major changes in PROJ, libgeotiff & GDAL are the result of the Barn
Raising:

 https://gdalbarn.com/

> What packaging mismatches are we going to encounter during the cross
> over period?

See some of the recent discussions on the proj list.

> Can we support multiple versions of proj libraries?

Not really.

> If so, we should be able to tell the story of which applications will be
> using which proj library for upcoming OSGeoLive releases.

All applications should be using the version of the proj package which
is in OSGeoLive.

This implies waiting with the upgrade to PROJ 6.x until most
applications support it, either by adopting proj.h or defining the
deprecated flag.

Some of the Debian packages have been updated (in git) to set the flag,
but I didn't continue because some of the important packages in
dependency level 1 failed to build with PROJ 6, see:

 https://lists.debian.org/debian-gis/2019/03/msg00004.html

I'm waiting for the PROJ 6.1.0 & GDAL 2.5 releases before trying the
rebuilds again. Especially the test failures in proj-rdnap are
concerning as this show a major regression when using certain datum grids:

 https://lists.osgeo.org/pipermail/proj/2019-March/008320.html

The lack of recent SpatiaLite final releases is also concerning:

 https://groups.google.com/d/msg/spatialite-users/eNkl3Ec8kfQ/fuLa4hHIAQAJ

Kind Regards,

Bas

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