GACOS.Import            Import GACOS product in R
GACOS.PhCor             GACOS Atmospheric Phase delay correction
Phase.to.disp           InSAR Unw-Phase to displacement
Phase.to.height         InSAR Unw-Phase to height
coh.mask                Mask image with coherence threshold
d.ztd                   Calculate ZTD difference between times
d.ztd.resample          Resample Di-ZTD to phase cell resolution and
                        match raster extents.
