[PROJ] Disable .local in 7.0.0RC default search paths

[Roger Bivand]

On Sun, 23 Feb 2020, Even Rouault wrote:

>> Where are these functions,
>
> This is documented in
> https://github.com/OSGeo/PROJ/blob/master/docs/source/usage/network.rst
> This will go live on proj.org once 7.0 has ben released.

Thanks, I guess the links will work once it is live - proj-ini isn't a 
function and grep doesn't find it in the 7.0.0 source, environment 
variables are potentially fragile (multiple loaded packages in an R 
session may try to set them), so the proj_context_set_enable_network() 
function may work.

However, in a long-running session is also not great. I've been creating 
and closing ctx handles before and after each use of PRØJ, I'll need to 
preserve the context for the duration of the session, I suppose, will I 
not? I think Edzer preseves a variable for axis order in the R sf package 
CPP namespace, but for rgdal, PRØJ was never "kept running".


>
>> and can they be securely turned off (confirmed
>> on load that CDN will not be used)? Later users or labs may turn them on,
>> but positive confirmation that they are off matters.
>
> The settings are off by default.
>
>> I've seen transient cases of rgdal loading, creating the
>> directory and putting cache.db in it, and other cases where no directory
>> is created, in otherwise identical settings.
>
> If you run "make check", as projsync is tested and other network 
> functionality too, the directory will be created and cache.db as well. 
> But for other uses when those functionality isn't enabled, they should 
> not.

Yes, this feels like the right explanation, I run make check often.

>
>> but if grids come into play, with a hash tag or similar of the specific
>> grid used - to be able to reproduce the output of the coordinate
>> operation. Will that be visible in the pipeline string returned?
>
> Only grids appearing explicitly in a pipeline string will be used (if
> providing explict pipelines. When using 'black-box' mode with
> proj_create_crs_to_crs(), grids may or may not be used). For a given
> coordinate operation returned by proj_create_operations(), you can get the
> grids used with proj_coordoperation_get_grid_used_count() +
> proj_coordoperation_get_grid_used())

I use this in the alternative workflow - list candidates and choose the 
best available, and go to proj_trans_* with a prepared pipeline. For 6, 
this was just giving the name of the grid - will 7 encode the part of the 
grid used, or will this also use the area of interest?

Roger

>
> Even
>
>

-- 
Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; e-mail: Roger.Bivand at nhh.no
https://orcid.org/0000-0003-2392-6140
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