Problem trying to download across 0 meridian

[Laurie Gainey]

I know that we have done this before, but running into a problem downloading HYCOM temperature and salinity data using the following geographic bounds:

50N to 80N

60W to 20E  (by specifying -60 to 20)

The resulting HYCOM file only has longitude data from 0 to 20E.

Any suggestions?

[Michael McDonald]

Laurie,

Unfortunately, NCSS does not support subsets that cross the prime meridian since west/east goes from 0 to 360. If you need to use NCSS then you must download both halves and combine the NC files locally, or get the whole domain and then cut/discard the domain parts you don't want (via local NCO tools like ncks), or simply use ncks to client-side subset via OPENDAP (i.e. don't use NCSS).

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Michael McDonald
HYCOM.org Administrator

[Laurie Gainey]

Thank you very much

 

From: Michael McDonald <michael....@hycom.org>
Sent: Wednesday, January 10, 2024 4:25 PM
To: Laurie Gainey <laurie...@gmail.com>
Cc: HYCOM.org Forum <fo...@hycom.org>; Laurie Gainey <lga...@highrezconsulting.com>
Subject: Re: Problem trying to download across 0 meridian

 

Laurie,

Unfortunately, NCSS does not support subsets that cross the prime meridian since west/east goes from 0 to 360. If you need to use NCSS then you must download both halves and combine the NC files locally, or get the whole domain and then cut/discard the domain parts you don't want (via local NCO tools like ncks), or simply use ncks to client-side subset via OPENDAP (i.e. don't use NCSS).

 

 

 

On Tue, Jan 9, 2024 at 4:17 PM Laurie Gainey <laurie...@gmail.com> wrote:

I know that we have done this before, but running into a problem downloading HYCOM temperature and salinity data using the following geographic bounds:

 

50N to 80N

60W to 20E  (by specifying -60 to 20)

 

The resulting HYCOM file only has longitude data from 0 to 20E.

Any suggestions?

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To ask a question, send an email to fo...@hycom.org

[Laurie Gainey]

We were just a bit confused because

GLBv.08/expt_57 allows you to download across the prime meridian, however GLBv.08/expt_93 and GLBv.08/expt_92 will not

 

 

From: Michael McDonald <michael....@hycom.org>
Sent: Wednesday, January 10, 2024 4:25 PM
To: Laurie Gainey <laurie...@gmail.com>
Cc: HYCOM.org Forum <fo...@hycom.org>; Laurie Gainey <lga...@highrezconsulting.com>
Subject: Re: Problem trying to download across 0 meridian

 

Laurie,

Unfortunately, NCSS does not support subsets that cross the prime meridian since west/east goes from 0 to 360. If you need to use NCSS then you must download both halves and combine the NC files locally, or get the whole domain and then cut/discard the domain parts you don't want (via local NCO tools like ncks), or simply use ncks to client-side subset via OPENDAP (i.e. don't use NCSS).

 

 

On Tue, Jan 9, 2024 at 4:17 PM Laurie Gainey <laurie...@gmail.com> wrote:

I know that we have done this before, but running into a problem downloading HYCOM temperature and salinity data using the following geographic bounds:

 

50N to 80N

60W to 20E  (by specifying -60 to 20)

 

The resulting HYCOM file only has longitude data from 0 to 20E.

Any suggestions?

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You received this message because you are a member of HYCOM.org
To ask a question, send an email to fo...@hycom.org

[Michael McDonald]

The Navy changed the longitude (west-east) format to 0-360 for all the latest Global model netcdf outputs. The older hycom outputs used to be -180 to 180, which had a similar issue with NCSS that prevented queries that spanned the 180deg line. This spanning/wrap issue was supposed to be fixed in the newer versions of NCSS that Unidata releases (v5+) but we have not yet upgraded our NCSS servers to this. 

 

[Laurie Gainey]

Thank you very much for the prompt reply ! 

Sent from my iPhone

On Jan 11, 2024, at 11:13 AM, Michael McDonald <michael....@hycom.org> wrote:



The Navy changed the longitude (west-east) format to 0-360 for all the latest Global model netcdf outputs. The older hycom outputs used to be -180 to 180, which had a similar issue with NCSS that prevented queries that spanned the 180deg line. This spanning/wrap issue was supposed to be fixed in the newer versions of NCSS that Unidata releases (v5+) but we have not yet upgraded our NCSS servers to this. 

 

On Thu, Jan 11, 2024 at 10:33 AM Laurie Gainey <lga...@highrezconsulting.com> wrote:

We were just a bit confused because

GLBv.08/expt_57 allows you to download across the prime meridian, however GLBv.08/expt_93 and GLBv.08/expt_92 will not

 

 

From: Michael McDonald <michael....@hycom.org>
Sent: Wednesday, January 10, 2024 4:25 PM
To: Laurie Gainey <laurie...@gmail.com>
Cc: HYCOM.org Forum <fo...@hycom.org>; Laurie Gainey <lga...@highrezconsulting.com>
Subject: Re: Problem trying to download across 0 meridian

 

Laurie,

Unfortunately, NCSS does not support subsets that cross the prime meridian since west/east goes from 0 to 360. If you need to use NCSS then you must download both halves and combine the NC files locally, or get the whole domain and then cut/discard the domain parts you don't want (via local NCO tools like ncks), or simply use ncks to client-side subset via OPENDAP (i.e. don't use NCSS).

 

 

 

On Tue, Jan 9, 2024 at 4:17 PM Laurie Gainey <laurie...@gmail.com> wrote:

I know that we have done this before, but running into a problem downloading HYCOM temperature and salinity data using the following geographic bounds:

 

50N to 80N

60W to 20E  (by specifying -60 to 20)

 

The resulting HYCOM file only has longitude data from 0 to 20E.

Any suggestions?

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Michael McDonald
HYCOM.org Administrator