[PROJ] ESRI deprecated CRS

[Nicolas Cadieux]

Hi Even,

> Regarding Nicolas's remark:
>> As you can see, there are small differences like the reversal of the 
>> standard parallel 1 and 2. Others will give you more information.
> 
> For LCC, you can switch std_parallel_1 and _2 indifferently.
> 

Thanks, for the clarification. That’s is what I thought.  I was always wondering if this was just down to some writing convention or if this switch really mattered. I’am really not a geodesic expert... 

Cheers!

Nicolas

> Le 6 janv. 2021 à 05:56, Even Rouault <even.rouault at spatialys.com> a écrit :
> 
> Javier,
> 
>> I do not know what does it mean. Has ESRI deprecated its own CRS, but
>> includes the EPSG one (btw, which one?)... with exactly the same info and
>> name?
> 
> I'm not sure. I suspect their 10xxxxx records might have pre-dated the EPSG 
> ones (or they didn't adopt them right away), and then they decided to use the 
> EPSG ones.
> 
>> The consequence is that it appears (only once) as deprecated in proj.db. Is
>> that intended?
> 
> Yes, proj.db reflects the information from the Esri database.
> 
>> 
>> Making this query
>> SELECT auth_name, code, name, deprecated FROM projected_crs WHERE name LIKE
>> "%Virginia%South%"
>> I realized that the deprecated ones are duplicated in a similar way in ESRI
>> file. The non deprecated ones (from CORS96) are not "duplicated" in the
>> ESRI file. Is there any reason behind that?
> 
> No idea. That's a question for Esri.
> 
>> A more general question: What does mean that a CRS is deprecated?
> 
> Probably depends on the producer. The meaning for EPSG is given in paragraph 
> "5.6.1 The Deprecated field" of Guidance Note 7-1. See
> https://epsg.org/guidance-notes.html
> 
> Regarding Nicolas's remark:
>> As you can see, there are small differences like the reversal of the 
>> standard parallel 1 and 2. Others will give you more information.
> 
> For LCC, you can switch std_parallel_1 and _2 indifferently.
> 
> 
> Even
> 
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