[PROJ] Call for review on RFC 4 text: Remote access to grids and GeoTIFF grids

[Jeff McKenna]

Hi Even,

On 2019-11-26 12:15 PM, Even Rouault wrote:
> Jeff,
> 
>> I would like this RFC to include effort to improve the documentation on
>> which grids should be installed (it is very confusing how
>> 'proj-datumgrid-latest' differs from world, europe, oceania,
>> northamerica, I always assume, like many others I bet, that -latest
>> includes europe+oceania+northamerica+world).
> 
> Can you point exactly in the documentation where would you want some
> clarification ?

That is difficult because the datumgrid information seems split into 
many pages.

- this page makes no mention of the difference between 
proj-datumgrid-latest, world, etc. 
https://proj.org/resource_files.html#external-resources

- install doc gives a little more info on which grids to install, but 
only for Conda, and doesn't link to the above page or Github 
https://proj.org/install.html

- links exist to the OSGeo download page, but there was no explanation 
of what 'proj-datumgrid-latest' contains anywhere 
(https://download.osgeo.org/proj/)

- I think most users will go directly to Github  and be overwhelmed by 
all of the different regions and world and proj-datumgrid-XX files 
(https://github.com/OSGeo/proj-datumgrid/releases)

Now you might say 'well jeff fix the docs, they are open' but honestly I 
don't know the answers to the above points.  Maybe I'm looking at too 
many pages (that I mentioned above) and should only focus on the 
README.md (https://github.com/OSGeo/proj-datumgrid), but again, that 
page should then be linked from the main PROJ site I believe.

Sorry for my confusion!

-jeff





> 
>> Which brings me to the most important point that I believe is missing in
>> the RFC, of notifying the user when a grid file is not leveraged.
>> Currently there is no warning, no notice, when a grid is not installed.
>> I side with Andrew Bell on his point that during installation I'd like
>> to see more messages, notices, or something to install all grid files.
>> Could there be a build option of "TEST_ALL_DATUMGRID_FILES" during PROJ
>> compilation?
> 
> Installation is a complicated topic. The PROJ project has no control over how
> PROJ is packaged and installed, and doing the "check at installation" means a
> different technical reality for Debian, Fedora, MS4W, OSGeo4W, conda, etc.
> That said I took note of Chris Crook's idea about a script to help, as a post-
> installation means (could potentially be run automatically by whatever
> installation process is done)
> https://github.com/OSGeo/PROJ/issues/1750
> 
> Even
> 


-- 
Jeff McKenna
MapServer Consulting and Training Services
https://gatewaygeomatics.com/