Re: PROJ 7.0.0

[Sebastiaan Couwenberg <sebastic@xs4all.nl>]

PROJ 7 adds support for datum grids in GeoTIFF format, as available via
the new CDN:

 https://cdn.proj.org/.

The grids are maintained in the PROJ-data repo:

 https://github.com/OSGeo/PROJ-data/

And are derived from the grids available in the proj-datumgrid repo:

 https://github.com/OSGeo/proj-datumgrid

I've somewhat reluctantly packaged the GeoTIFF grids (#952459). The
proj-data source package currently builds the proj-data-grids binary
package which contains everything.

Like the regional datumgrid archive, the size is quite large. One of
reasons I was reluctant to package the grids.

We should probably build separate binary packages for every country,
possibly even per agency, but the latter will make it hard for users to
determine which package they need to install (if they don't know about
apt-file). Per country packages is more intuitive. If we do this, we'll
have the proj-data-grids package depend on all other grid packages.

The FTP masters may have objections to the package in its current shape too.

In the worst case scenario users will have to enable the network (by
using the PROJ_NETWORK=ON environment variable or editting
/usr/share/proj/proj.ini) to have access to the grids via the CDN. This
is already a great improvement over having to download the regional
proj-datumgrid archive and unpacking them in PROJ_LIB manually.

Kind Regards,

Bas

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