%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%dial2gravity.m
% this function converts gravimeter dial readings to gravity, 
% using the part of the data sheet relevant to our field area.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



function gravity = dial2gravity (dial_reading)

%gravimeter data
datasheet = [ 	[2900 3000 3100 3200 ]
		        [3058.5 3164.06 3269.63 3375.22] 
		        [1.05562 1.05574 1.05587 1.005598]];

%loop over readings
for j=1:length(dial_reading)
	dial = dial_reading(j);
	
	if ((dial < 2900) | (dial > 3299))
		continue;
	%find Milligal and interval values
	end
	
	for i=1:4
		if (floor( dial_reading(j)/100) == datasheet(1, i)/100 )
			datasheetvalue = datasheet(1, i);
			intervalvalue= datasheet(3, i);
			millgalvalue = datasheet(2, i);
		tableline =i;
		break;
		end
	end
	
	%calculate offset (reading - table)
	offset = dial - datasheet(1,tableline);

	%multiply by interval value
	offset = offset * intervalvalue;
	
	%add to reading
	gravity(j) = millgalvalue + offset;
end