New USGS database

Intro

There was a problem with the USGS "landfrac" data base (saved at /asl/data/usgs/) - it mixed USGS and a UMD land use database (to find rivers,etc...). This had the problem of erasing the Pacific Islands.

Another database was created (/asl/data/usgs/world_grid_deg10_v2.mat), at 1/10 deg resolution but at this time only using the original USGS 1/120 deg database.

In order to use this database, I changes a few defaults:

• rtpadd_usgs_10dem.m - now reads by default "/asl/data/usgs/world_grid_deg10_v2.mat" file. There's an option to override this choice. Also saves previously defined landfrac and salti into udefs.

To do

For arbitrary grid resolution there is the routine "usgs_degN.m". This routine reads the above database and re-grids the results. This still used the old database.