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Re: netCDF construct for 24-bit RGB?

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  • Subject: Re: netCDF construct for 24-bit RGB?
  • Date: Tue, 01 Mar 2005 12:55:35 -0700
>To: Russ Rew <address@hidden>, Ed Hartnett <address@hidden>
>From: Lou Estey <address@hidden>
>Subject: Re: 20050217: netCDF construct for 24-bit RGB?
>Organization: UNAVCO
>Keywords: 200502171746.j1HHkLv2015284

Hi Lou,

It looks like your question fell through the cracks.  If you send
questions to "address@hidden" they get tracked a little
better and routed to someone who is available, rather than on vacation
or out of town.

> I have another nagging question.  Is it possible to
> have a netCDF file hold 24-bit RGB values (8-bit red,
> 8-bit green, 8-bit blue)?  In particular, say, a
> lon/lat grid of 24-bit RGB, i.e. an image?  (Plus
> it would be better if the storage were sequences
> of RGB byte-triplets.)

There is no 24-bit integer type in netCDF.  However, you can define a
byte variable dimensioned like this (I'm using CDL notation):

  dimensions:
     rgb = 3;
     lon = 50;
     lat = 60;
  variables:
     byte image(lon, lat, rgb);

which would waste no space and store RGB values contiguously for each
lon/lat point.

--Russ