function bouganom = model2(rho1, rho2, dip, dist, ht, meas, base);
%bouganom = model2(rho1, rho2, dip, dist, ht, meas, base);
%	computes the Bouguer anomaly assuming a tilted plane of rock 
%	lies below the sediment, dipping towards the closer data points.
%		rho1 = density of sediment	(g/cm^3)
%		rho2 = density of rock		(g/cm^3)
%		dip  = apparent dip of rock-sediment interface	(degrees)
%		dist = vector of horizontal distances to data points	(m)
%		ht   = vector of measured altitudes of data points	(m)
%		meas = vector of measured gravity values	(mgal)
%		base = which row of the vectors is the base station
%	output is a vector of Bouguer anomaly values (mgal)

rockslope = tan(dip*pi/180);
rockht = rockslope * dist;  % y-intercept is irrelevant

bougcorr = 2*pi*rho1*6.673e-8*(ht - rockht)*1e5 + ...  % sediment
           2*pi*rho2*6.673e-8*rockht*1e5;              % rock

sealevel = 6371000;
facorr = 2 * ht / sealevel * 9.8e5;		% free air approx

bouganom = meas + facorr - bougcorr;   % make the corrections
bouganom = bouganom - bouganom(base);  % zero anomaly at base station