what does the system do if the admin doesnt set a value for that
dataset?
ncWMS scans each dataset when it's first loaded into the system and makes a test extraction of a chunk of data from the first timestep and first z level from each variable. Then it finds the min and max of this data subset, adding 10% at top and bottom. It's far from perfect but it at least gives a reasonable guess, which the sysadmin can override if it turns out to be a bad choice.
If that doesn't work for any reason, ncWMS applies the default range [-50:50]. But this doesn't happen very often.
The estimated scale ranges are persisted to the ncWMS config file so they don't have to be recalculated when the server is rebooted.
I guess this approach would be difficult to apply in TDS, where the data catalogs could be very big.
Jon
NOTE: All email exchanges with Unidata User Support are recorded in the Unidata inquiry tracking system and then made publicly available through the web. If you do not want to have your interactions made available in this way, you must let us know in each email you send to us.