[gdal-dev] How to represent multi-dimensional array

[Lucena, Ivan]

Chris,

Christopher Barker wrote:
> Hi folks,
> 
> I have a dataset that is a 4-dimensional array of values: time,x,y,z
> 
> We're currently using netcdf to store it, which is well suited to this 
> kind of data.
> 
> However, we also need to get it into a GIS (Arc in this case), and I'm 
> trying to find a good way to do that.
> 
> Both Arc and gdalinfo do strange things if I simply point them at the 
> netcdf file. GDAL seems to (arbitrarily?) see it as a 9064 band data 
> set, so it is taking particular slice (I think I'm getting a bunch of 
> (time, z) 2-d bands.

You might take a look a Idrisi (www.clarklabs.org). It imports netCDF using a GUI where you can 
choose the orders of the dimensions to read from. There is a set of tools to perform time series 
analysis.

> Anyway, I suspect that if I re-arrange the axis in the netcdf file, I 
> might get something more reasonable, but my question is:
> 
> What is a good format to ex[press this to a GIS system?
> 
> I'm imaging multiple files, maybe geo-tiff, but how to I express time 
> and elevation in a way that is natural to GIS?

You might be forced to use multiple files just because that is how generally image processing tools 
work better. Then you could write scripts to loop trough the bands files with those tools.

Although some operations on the time dimension could work much faster in a multi-band, pixel 
interleaving storage mode. Like you said, netCDF are well suited for that kind of processing. I am 
afraid that the tools are not, yet.

> thanks for your thoughts,
> 
> -Chris

Regards,

Ivan