#!/bin/csh
#
# Version from 23 October 2000.
# I need to do some tests and remind myself why the 7.5 mGal noise level was set.
# One test I did was to look in -R-42/-40/-41/-39 (Agulhas abyssal plane; average
# depth 5150 m) where the rms was about 7.2 mGal.  I noted that applying erf to
# this with a sigma of 7.5 did not change things much.  The img_erf -V program scales
# by (sigma * M_SQRT2).  For sigma = 7.5, a 5 mGal anomaly is cut to 2.5, while
# by 20 mGal and greater there is essentially no change.
#
# Version for 23 February 2009:
# I first high-passed the gravity and looked at the same Agulhas area, and got
# about 2.0 mGal noise (at sea level), so I used img_erf to take that out before
# doing the downward continuation and draping.  This was in grav_down.com
# Then I checked the Agulhas area again after downward continuing, and I got 3.3
# mGal.  The old script from 23oct2000 used 7.5 mGal on the first few passes and
# then 6.0 on the last pass.  So here I follow the same, but using 3.3 on the 
# first ones and then (6/7.5)*3.3 = 2.6 on the last pass:
#
#
#Compute estimated short-wavelength topography to fit gravity:
#
#Get first guess by using down-draped gravity, with erf correction of 7.5 mGal sigma:
#
./src/img_erf -V grav_drape.img  -Otopo1.img -S33.0 -T1.454
./src/img_parker topo1.img -Opark1.img -P7/0.6876  -N576 -V -W
#
./src/img_diff grav_drape.img park1.img > diff.img
./src/img_erf -V diff.img  -Otopo_perturb.img -S33.0 -T1.454
./src/img_sum topo1.img topo_perturb.img > topo2.img
./src/img_parker topo2.img -Opark2.img -P7/0.6876  -N576 -V -W
#
./src/img_diff grav_drape.img park2.img > diff.img
./src/img_erf -V diff.img  -Otopo_perturb.img -S26.0 -T1.454
#
./src/img_sum topo2.img topo_perturb.img > topo3.img
#
mv topo3.img bandpass_t_from_nonlin_g.img
rm topo?.img park?.img diff.img topo_perturb.img