[PROJ] Get PROJ description in PROJ 5?

[Matthew Woehlke]

On 19/03/2021 12.52, Sebastiaan Couwenberg wrote:
> On 3/19/21 5:36 PM, Matthew Woehlke wrote:
>> Sigh... looks like I need a pile of version-checking code.
> 
> Why bother with PROJ 5 support at this point in time, you can just focus
> on supporting PROJ 6+.

Because PROJ 6 doesn't support the PROJ 4 API (without code changes, 
anyway), and we get PROJ from an external repo. This leads to a 
chicken-and-egg problem; we can't bump to providing PROJ 6 because our 
project will break, and we can't use the PROJ 6 API because we don't 
*have* PROJ 6.

So far, I've bumped us to providing PROJ 5; we can still build against 
that using the PROJ 4 API. Now I'm working on updating our usage to PROJ 
5, with PROJ 6 support. It's not pretty, but it's not as bad as two 
totally separate implementations, which is what we'd just about have to 
do with PROJ 4 + PROJ 6.

Given how much of a headache this has been, and that we still have other 
projects using PROJ 4, I suspect we may not try to move to PROJ 6 until 
it becomes absolutely necessary. (At which point there is some hope some 
of the other code still on PROJ 4 will be effectively dead.)

It doesn't help that code that works with PROJ 5 is broken with PROJ 6.

-- 
Matthew