The grids that was previously available via the proj-datumgrid packages are now available in two places:
- The new PROJ-data package
- From the cloud via https://cdn.proj.org
The PROJ-data package includes all grids and other resources previously tracked by the proj-datumgrid series of packages as well as some new grids. All grids in the PROJ-data package have been converted to the new Geodetic Tiff Grid (GTG) format introduced in PROJ with RFC4. The advantages of the GTG format are
- Grids can contain more metadata than previous formats used by PROJ
- Grids are compressed, taking up significantly less space
- Cloud optimized, for easy on-the-fly access to grids online via https://cdn.proj.org/
- Advanced gridded models previously consisting of several files can now be contained in one file
The data in the PROJ-data package is mirrored on https://cdn.proj.org/. A network-enabled PROJ build can leverage the CDN and retrieve (parts of) grids as specific transformations need them on the fly.
PROJ-data can only be used with PROJ 7.0.0 and newer.
Provided with PROJ is a utility called projsync that can be used download grids from the data store in the cloud.
The use of the new grid format and the data from the cloud requires that PROJ is build against libtiff and libcurl. Both are optional dependencies to PROJ but it is highly encouraged that the software is build against both.
PROJ 7.0.0 and the accompanying PROJ-data package can be download here:
In addition the PROJ-data package the old proj-datumgrid series of packages has also been updated, to extend the life-time of the PROJ 6.x branch a bit longer. These will be the last updates to the proj-datumgrid packages. The Updated packages can be downloaded here:
ATTENTION: PROJ 7 will be last major release version that includes the proj_api.h header. The functionality in proj_api.h is deprecated and only supported in maintenance mode. It is inferior to the functionality provided by functions in the proj.h header and all projects still relying on proj_api.h are encouraged to migrate to the new API in proj.h. See https://proj.org/development/migration.html for more info on how to migrate from the old to the new API.
The release notes are available at the PROJ website.