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26 Sep 2020
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No wave data on XyGrib 1.1.0 6 years 4 months ago #102

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I'm using the latest version of XyGrib 1.1.0 on OpenPlotter and for about three weeks now I've been seeing that even though I'm doing the request correctly, the wave data is either not downloaded or is downloaded in the wrong format.

As I was cruising the pitiusas I didn't spend any more time thinking that it would be a specific problem of the build for Raspberrt Pi, but after returning home and trying the APPimage I see that the problem continues. Is there any problem with the wave data servers? Until mid-July they seemed to work correctly. :(

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Last edit: by tu.

No wave data on XyGrib 1.1.0 6 years 4 months ago #103

Thanks for the feedback.
The issue is related to the JPEG2000 packing of the wave gribs. This was started about mid July.
There is no problem to handle this compression if the correct openJpeg library is used. This should be the one internally provided version in the v1.1.0 package. If a different version of library was installed or used the compression might not be handled.
Regarding the AppImage - I need to check this as it should have been build using the correct openjpeg library.

The next release also needs openJpeg > 2.x and as long as it is used there is no problem with GRIB2 files using JPEG2000 packing. Unfortunately in GRIB2 JPEG2000 is the only available compression for wave data. Other data uses C3 packing which is better and faster.

David
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No wave data on XyGrib 1.1.0 6 years 4 months ago #104

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Thank you for your answer, Davidgal. The truth is that I don't quite understand it. Forgive my clumsiness.

You mean the library I have installed on my system, in this case libopenjp2-7? should I install another version?

Both Ubuntu 18.04 and OpenPlotter have the same library installed. In both cases the behaviour is the same:

If I use APPimage 1.0.1 I can easily download the wave data. In addition, these wave data can be read correctly by both APPimage 1.0.1 and 1.1.0. But....
if I download the wave data with APPimage 1.1.0 none of the other versions of APPimage is able to read the data.

Exactly the same behavior happens with the two versions compiled by me for OpenPlotter. The truth is, I wouldn't know how to fix it. I'm missing something.

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No wave data on XyGrib 1.1.0 6 years 4 months ago #105

Hi tu,

I checked deeper and I was mistaken. Sorry!

The combination of libpng, libopenjp and g2clib in XyGrib version 1.1.0 does not handle Jpeg2000 compression. Therefore the wave records were not being read at all. This applies to all Linux builds. Windows build of v1.1.0 is able to handle Jpeg2000.

I have immediately stopped the Jpeg2000 compression for wave data in the opengribs grib server so all builds of v1.1.0 can read wave data.

The next release (v1.1.1) is OK with Jpeg2000. I will at some point after the next release, reactivate the Jpeg2000 packing on the grib server.

Thanks for your inputs and I'm happy to help

David

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Last edit: by davidgal.

No wave data on XyGrib 1.1.0 6 years 4 months ago #106

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Big thanks David.

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