[gdal-dev] How to wrap a zarr in a zip and read it with vsizip?

[Kurt Schwehr]

Thanks Laurentiu and Scott!

I can't believe 1) I left off -r and 2) I didn't think to look at what's in
the zip. Doh!

And thanks for reminding me about sozip. I was one of the reviewers of the
initial spec and still don't have it front-of-mind.

unzip -l nczarr_v2.zarr.zip
Archive:  nczarr_v2.zarr.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
        0  2024-12-23 02:00   nczarr_v2.zarr/
---------                     -------
        0                     1 file

Now happily able to see the contents:

gdalinfo /vsizip/nczarr_v2.zarr.zip/nczarr_v2.zarr
Driver: Zarr/Zarr
Files: /vsizip/nczarr_v2.zarr.zip/nczarr_v2.zarr
Size is 512, 512
Subdatasets:

SUBDATASET_1_NAME=ZARR:"/vsizip/nczarr_v2.zarr.zip/nczarr_v2.zarr":/MyGroup/lon
  SUBDATASET_1_DESC=Array /MyGroup/lon

SUBDATASET_2_NAME=ZARR:"/vsizip/nczarr_v2.zarr.zip/nczarr_v2.zarr":/MyGroup/lat
  SUBDATASET_2_DESC=Array /MyGroup/lat

SUBDATASET_3_NAME=ZARR:"/vsizip/nczarr_v2.zarr.zip/nczarr_v2.zarr":/MyGroup/dset1
  SUBDATASET_3_DESC=Array /MyGroup/dset1

SUBDATASET_4_NAME=ZARR:"/vsizip/nczarr_v2.zarr.zip/nczarr_v2.zarr":/MyGroup/Group_A/dset2
  SUBDATASET_4_DESC=Array /MyGroup/Group_A/dset2

SUBDATASET_5_NAME=ZARR:"/vsizip/nczarr_v2.zarr.zip/nczarr_v2.zarr":/MyGroup/Group_A/dset3
  SUBDATASET_5_DESC=Array /MyGroup/Group_A/dset3
[SNIP]

-Kurt

On Mon, Feb 24, 2025 at 11:21 AM Laurențiu Nicola via gdal-dev <
gdal-dev at lists.osgeo.org> wrote:

> I suspect it won't make a lot of difference. SOZIP is designed to allow
> seeking within a compressed file, but Zarr is tile- (block) based, where
> each of those is stored in a different file. So you end up uncompressing a
> whole file anyway.
>
> Laurentiu
>
> On Mon, Feb 24, 2025, at 21:17, Scott via gdal-dev wrote:
> > There's GDAL's sozip (Search Optimized Zip) utility as well. I have no
> > idea if it works with .zarr. I'm sure someone will correct me! ;)
> >
> > cd nczarr_v2.zarr
> > sozip ../nczarr_v2.zarr.zip .
> > sozip -l /vsizip/../nczarr_v2.zarr.zip
> >
> > On 2/24/25 10:09, Kurt Schwehr via gdal-dev wrote:
> >> Hi all,
> >>
> >> I seem to be having trouble exactly how to correctly make a zip of a
> >> zarr and how to correctly specify the vsizip url.
> >>
> >> e.g from autotest/gdrivers/data/zarr
> >>
> >> gdalinfo nczarr_v2.zarr # Works
> >> tar cf nczarr_v2.zarr.zip nczarr_v2.zarr
> >>
> >> Then what? I've tried lots of variations and not had any success.
> >>
> >> Thanks!
> >> -Kurt
> >>
> >> _______________________________________________
> >> gdal-dev mailing list
> >> gdal-dev at lists.osgeo.org
> >> https://lists.osgeo.org/mailman/listinfo/gdal-dev
> >
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