I have three arrays of size npts=42164. They are LON, LAT and DATA. They contain meteorological data over the ocean. I need to transform the DATA array from one-dimension to two, but need to do it quickly (i.e. no "do loops"). LON and LAT contain the longitude and latitude of the nth point. Data contains some variable, say sea surface temperature. Note that the arrays only have valid data over the oceans and not over land (that's the catch). So what I need is the following: Using info in LON and LAT, transform DATA[npts] -> DATA2[nlon,nlat], where nlon=360 and nlat=180 (Global coverage). This could easily be done with loops, but it is much too slow. I need some way to make this transformation very quickly. Thanks to anyone willing to help out. David Wolff NASA GSFC