[PROJ] Unexpected conversion behaviour.

[Even Rouault]

Hi Chris,


I see in pj_get_suggested_operation() a  normalizeLongitude() longitude 
that renormalize longitudes to [-180,180]. Perhaps this is related to 
how you've defined the area of use of your transformation?  It should be 
something like 
min_lat,longitude_a_bit_below_180,max_lat,longitude_a_bit_above_minus_180 
for an area of use intersecting the antimeridian.


Even


Le 20/12/2024 à 01:16, Chris Crook via PROJ a écrit :
>
> UNCLASSIFIED
>
>
> Hi PROJ people
>
> I am looking at a conversion (EPSG:4176->EPSG:4272) which is 
> lat/lon->lat/lon via a distortion grid.  Unexpectedly I get a 
> different answer by adding 360 degrees to the input coordinate.
>
> It looks like this possibility is not accounted for when testing 
> whether the grid is applicable, so it falls back to the less accurate 
> option.   Is that correct? And if so would it make sense to allow 
> longitude wrapping when evaluating conversion options?
>
> $ test_nzgd1949.sh
> + cs2cs
> Rel. 8.2.1, January 1st, 2022
> usage: cs2cs [-dDeEfIlrstvwW [args]]
>               [[--area name_or_code] | [--bbox 
> west_long,south_lat,east_long,north_lat]]
>               [--authority {name}] [--accuracy {accuracy}] [--no-ballpark]
>               [+opt[=arg] ...] [+to +opt[=arg] ...] [file ...]
> + echo -42 173
> + cs2cs EPSG:4167 EPSG:4272 -d 8
> -42.00171693    172.99984072 0.00000000
> + echo -42 -187
> + cs2cs EPSG:4167 EPSG:4272 -d 8
> -42.00169999    172.99986158 0.00000000
>
> Thanks
>
> *Chris Crook ** (**he/him 
> <https://www.publicservice.govt.nz/our-work/diversity-and-inclusion/pronoun-use-in-email-signatures/>**)*
> Geodetic Scientist
>
> Location Information
>
> ccrook at linz.govt.nz <mailto:ccrook at linz.govt.nz> | *DDI *04 460 0567 | 
> *MOB* 021 027 44211
>
> _cid:image001.png at 01D622F4.BA10B4F0 <https://www.linz.govt.nz/>_
>
> 	
>
> Wellington Office, Level 7, Radio New Zealand House, 155 The Terrace
> PO Box 5501, Wellington 6145, New Zealand
>
> _www.linz.govt.nz <http://www.linz.govt.nz/>_ | _data.linz.govt.nz 
> <http://www.data.linz.govt.nz/>_
>
> _cid:image002.png at 01D6342C.DB5A4560 
> <https://www.facebook.com/landinformationnz/>__cid:image004.png at 01D6342C.DB5A4560 
> <https://www.linkedin.com/company/land-information-new-zealand/>__cid:image006.png at 01D6342C.DB5A4560 
> <https://twitter.com/LandInfoNZ>__cid:image011.png at 01D6342C.DB5A4560 
> <https://www.youtube.com/user/linzvideoofficial>_
>
>
>
> ------------------------------------------------------------------------
>
> This message contains information, which may be in confidence and may 
> be subject to legal privilege. If you are not the intended recipient, 
> you must not peruse, use, disseminate, distribute or copy this 
> message. If you have received this message in error, please notify us 
> immediately (Phone 0800 665 463 or customersupport at linz.govt.nz) and 
> destroy the original message. LINZ accepts no responsibility for 
> changes to this email, or for any attachments, after its transmission 
> from LINZ. Thank You.
>
> UNCLASSIFIED
>
>
> _______________________________________________
> PROJ mailing list
> PROJ at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/proj

-- 
http://www.spatialys.com
My software is free, but my time generally not.
Butcher of all kinds of standards, open or closed formats. At the end, this is just about bytes.
Mood of the day: "Bien entendu, on peut sauter sur sa chaise comme un cabri en disant : les standards ! les standards ! les standards ! Mais ça n’aboutit à rien et ça ne signifie rien." ~ dixit De Gaulle
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20241220/6c2c928b/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Outlook-cid_image0.png
Type: image/png
Size: 7275 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20241220/6c2c928b/attachment-0005.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Outlook-cid_image0.png
Type: image/png
Size: 809 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20241220/6c2c928b/attachment-0006.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Outlook-cid_image0.png
Type: image/png
Size: 856 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20241220/6c2c928b/attachment-0007.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Outlook-cid_image0.png
Type: image/png
Size: 700 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20241220/6c2c928b/attachment-0008.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Outlook-cid_image0.png
Type: image/png
Size: 1064 bytes
Desc: not available
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20241220/6c2c928b/attachment-0009.png>