[gdal-dev] NetCDF and EASE-2

[Marsh, Chris]

Hi Even,
I see, Ok I think that all makes sense. Thanks very much!

Cheers
Chris

Chris Marsh, PhD
University of Saskatchewan
chrismarsh.ca<http://chrismarsh.ca/>



On Mon, Feb 3, 2020 at 12:45 PM Even Rouault <even.rouault at spatialys.com<mailto:even.rouault at spatialys.com>> wrote:
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On lundi 3 février 2020 17:36:45 CET Marsh, Chris wrote:
> Yup, forgot to enable netcdf. Sorry about that.
>
> Otherwise your directions worked perfectly, thank you very much!
>
> In terms of understanding, exactly, these steps for the next time:
>
> 0) How would I have known the data were transposed lon, lat?

gdalinfo NETCDF:"SD_20160901.nc":snd_upd
reporting
Warning 1: No UNIDATA NC_GLOBAL:Conventions attribute
and
metadata with the lat and lon variables was a hint

"ncdump SD_20160901.nc" showing "float snd_upd(lon, lat)" confirmed it

> 0b) How would I have known the spacing of the lat variable was not constant?

Computing differences on consecutive lat values in the ncdump output. But
gdalinfo with "--debug on" also reports "Longitude is not equally spaced" (it
is confused here because of the lon/lat inversion, so this must be understood
as the latitude...)

> 1) What is the motivation to tiling the output?

So that transposition of the array works fast.

> 3) I don't understand this step.  Why is this referencing back  the nc
> file?

Because previous steps have lost the georeferencing

Even

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