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<p>Michael,<br>
</p>
<div class="moz-cite-prefix">Le 15/03/2022 à 06:06, Michael Sumner a
écrit :<br>
</div>
<blockquote type="cite"
cite="mid:CAAcGz98BDCBRC+=U6UC9A7LhrQGdO=pfUd5pt5Od=+i2_VmMDA@mail.gmail.com">
<div dir="ltr">Hi,
<div><br>
</div>
<div>these files don't present to GDAL with a CRS, but it seems
not out of place to assume that they can use
'oSRS.SetWellKnownGeogCS("WGS84")', when no other indication
is found and there are dimensions 'lon,lat' or
'longitude,latitude'</div>
<div><br>
</div>
<div><a
href="https://www.ncei.noaa.gov/data/sea-surface-temperature-optimum-interpolation/v2.1/access/avhrr/"
moz-do-not-send="true" class="moz-txt-link-freetext">https://www.ncei.noaa.gov/data/sea-surface-temperature-optimum-interpolation/v2.1/access/avhrr/</a><br>
<div><br>
</div>
<div>An example sds specifically: </div>
<div><br>
</div>
<div>/vsicurl/NETCDF:"/vsicurl/<a
href="https://www.ncei.noaa.gov/data/sea-surface-temperature-optimum-interpolation/v2.1/access/avhrr/202202/oisst-avhrr-v02r01.20220201.nc"
moz-do-not-send="true" class="moz-txt-link-freetext">https://www.ncei.noaa.gov/data/sea-surface-temperature-optimum-interpolation/v2.1/access/avhrr/202202/oisst-avhrr-v02r01.20220201.nc</a>":sst</div>
<div><br>
</div>
<div>Would that be reasonable? Perhaps controlled by an env
var? Is there an established control for this I'm missing?
(I'm not looking for '-a_srs' or VRT, I want the
auto-detection to work for these and many other similar file
sources without augmentation). <br>
</div>
</div>
</div>
</blockquote>
<p>I wouldn't expose WGS84 by default, because it might be another
Earth geographic CRS, or even a non-Earth geographic CRS.</p>
<p>Potential solution:</p>
<p>- add a GDAL_NETCDF_DEFAULT_GEOGRAPHIC_CRS configuration option
(that could be set to EPSG:4326 e.g) that would be used in the
situation where the netCDF CF attributes to define a geographic
CRS, but without the actual CRS definition, are not set.</p>
<p>- or, more involved but more powerful, add a configuration file
in data/ , let's say a netcdf_product_conf.json or whatever, where
you would define a set of product types, with matching global
attributes and their values and the corresponding CRS.</p>
<p>e.g (not sure my set of "matching_attributes" is appropriate for
your use case)<br>
</p>
{<br>
"product_type": {<br>
"noaa_ncei_oisst": { // the id of the product here is
completely arbitrary<br>
"defining_global_attributes": {<br>
"title": "NOAA/NCEI 1/4 Degree Daily Optimum
Interpolation Sea Surface Temperature (OISST) Analysis, Version 2.1
- Final",<br>
"geospatial_lat_units": "degrees_north",<br>
"geospatial_lon_units": "degrees_east"<br>
},<br>
"default_values": {<br>
"crs": "EPSG:4326"<br>
}<br>
}<br>
}<br>
<p>}</p>
<p>- or, both the easiest and hardest one, convince the data
producer to just use the netCDF CF conventions to their full
capabilities.<br>
</p>
<p>Even<br>
</p>
<blockquote type="cite"
cite="mid:CAAcGz98BDCBRC+=U6UC9A7LhrQGdO=pfUd5pt5Od=+i2_VmMDA@mail.gmail.com">
<div dir="ltr">
<div>
<div><br>
</div>
<div>(It's not out of the question that I could submit a PR
for this, just flagging discussion in case I'm missing
something.)</div>
<div><br>
</div>
<div>Thanks. </div>
<div><br>
</div>
<div>Best, Mike</div>
<div><br>
</div>
<div><br>
</div>
-- <br>
<div dir="ltr" class="gmail_signature"
data-smartmail="gmail_signature">Michael Sumner<br>
Software and Database Engineer<br>
Australian Antarctic Division<br>
Hobart, Australia<br>
e-mail: <a href="mailto:mdsumner@gmail.com" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">mdsumner@gmail.com</a></div>
</div>
</div>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
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</blockquote>
<pre class="moz-signature" cols="72">--
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My software is free, but my time generally not.</pre>
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