[Gdal-dev] Re: GDAL netcdf convention CF support

[Gerry Creager N5JXS]

Frank, et al,

I think we need to be thinking either about making GDAL more interested 
in 3D/4D datasets, as that's coming whether we're ready or not... in 
fact, for me, it's already here.. and then see if we need to consider 
forking or augmenting Mapserver to accommodate it.

I see a lot of conceptual problems for Mapserver, and, for that matter, 
a LOT of GIS packages in incorporating 3D/4D data, and presenting it 
properly.  This has been an issue for GIS practitioners since just about 
  forever: They think in 2 dimensions and can't, as a group, appreciate 
the need for either vertical, or time.  They represent time series data 
as a series of static images.

I see, in Mapserver, a potential interface.  It's open-source and thus 
maleable for applications like this.  It won't be simple or 
straightforward, and in the end, Mapserver might serve solely as an 
example framework for a new 3D/4D display/dissemination tool, but it 
*is* a starting point.

I'm kinda thinking about a melding of Mapserver and IDV, in th elong run.

gerry

Frank Warmerdam wrote:
> On 8/18/05, Woolf, A (Andrew) <A.Woolf at rl.ac.uk> wrote:>  > This is great news, a good step along the road we're all headed. Norman> mentioned what is also the end game for us - the WCS *spec* supports> arbitrary 1-,2-,3- or 4-d slices in a fully 4-d dataset, eg: >   > •3-d volume (lat-lon-height): > > http://glue.badc.rl.ac.uk/cgi-> > bin/mapserv?REQUEST=GetCoverage&SERVICE=WCS&Version=1.0.0&Cov> > erage=temperature&BBOX=-180,-> > 90,179,90,0,1000&CRS=some3dCRS&FORMAT=CF-netCDF > •Hovmuller (lat vs time): > > http://glue.badc.rl.ac.uk/cgi-> > bin/mapserv?REQUEST=GetCoverage&SERVICE=WCS&Version=1.0.0&Cov> > erage=temperature&BBOX=10,-> > 90,10,90,500,500&TIME=1996/2005/1&CRS=some3dCRS&FORMAT=CF-netCDF> •Vertical slice through atmosphere (lat vs height): > > http://glue.badc.rl.ac.uk/cgi-> > bin/mapserv?REQUEST=GetCoverage&SERVICE=WCS&Version=1.0.0&Cov> > erage=temperature&BBOX=10,-> > 90,10,90,0,1000&CRS=some3dCRS&FORMAT=CF-netCDF >   > These are all *valid WCS requests*!!!
 !
>  My understanding, however, is that> fundamental 2-D limitations in GDAL will make this extremely difficult to> achieve in Mapserver - any views to the contrary? 
> Andrew,
> Indeed, as things stand in GDAL and MapServer it would be hardto achieve support for 3D and 4D datasets smoothly.   It might bepossible to "hack something up", but I'm not sure how desirablethat would be.  At best, it would be fragile and/or dependent onalot of extra configuration information in MapServer which wouldinternally still need to treat results as stacks of 2D bands. 
> Best regards,-- ---------------------------------------+--------------------------------------I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.comlight and sound - activate the windows | http://pobox.com/~warmerdamand watch the world go round - Rush    | Geospatial Programmer for Rent
> 

-- 
Gerry Creager -- gerry.creager at tamu.edu
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