Re: NetCDF conventions for mobile stations

Hi Janine:

Im unclear if you plan on putting all of these variations in the same file? My 
first choice might be to put them in multiple files. The formats that you seem 
to have:

1) station data
2) track data
3) station data that occasionally moves.

Our format for this kind of data is here:

http://www.unidata.ucar.edu/software/netcdf-java/formats/UnidataObsConvention.html

which covers 1 and 2. we havent dealt with 3 before, but we can come up with 
some variant. these are not part of the CF spec, but we plan to submit them.

perhaps you should look at the above spec, then we can talk some more.

Janine Goldstein wrote:
Hi John,

I am over at EOL and am wondering if you are the right person to help me. I am developing a netCDF file to contain data from irregularly spaced surface stations. Most of these are fixed with respect to time (i.e. ASOS stations, etc) but some move continuously with time (ships) or move intermittently, maybe even just once (as in stations that are relocated but keep the same station id, or truck mounted stations used during field deployments which are stationary for a few hours to a few days, and then move and are stationary again.

I am wondering how best to implement this within a CF compliant netCDF file. For fixed stations, I currently have:

parameter(time, station)
time(time)
lat(station)
lon(station)

I can change this to:

lat(time, station)
lon(time, station)

but less that 1% of the stations are mobile, so this seems like a huge waste of space. For example, 2 months worth of 5 minute data = 17280 repetitions of the lat/lon for each fixed station, compared to one instance of lat/lon in my current model, and I have hundreds of stations per file.

Do you have any suggestions as to how to implement this? Can you point me at any resources that try to tackle this problem?

I just wanted to check before I reinvent the wheel (-:

Thanks so much,

Janine Goldstein
NCAR/EOL