Question gmt. Calculate the analytical signal

Hi guys, I would like to know if anyone knows how I can calculate the analytical signal to highlight edges and tilt derivate as filters in some anomaly map, for example in this free air anomaly map earthfaa3m.grd, I would greatly appreciate the help!

Not near my text books and cannot recall definition of analytical signal for a 2-D faa grid. Might involve an FFT and some algebra? If so, you may ber able to compute it via grdfft and grdmath? If you have an equation we maybe able to comment more, but guessing @WHFSmith knows this stuff.

Of course, I forgot to put them in, these are the equations, the TRD is the tilt derivative and AS is for the analytical signal.

tilt signal

What I don’t understand is how to manipulate those equations, because I can calculate those derivatives that come out with grdfft -D or -A depending on the direction, so I use those grids resulting from the derivatives and make the equations with grdmath?

Some 30 y ago, still in my Fortran times I think, I played around with the analytical signal but have only faint memories of it. What I remember is that it was very at fashion at the time but fade down because the results were poorly satisfactory for real cases and the method suffered a lot from non-uniqueness.

And yes, you can try to used grdmath to compute that equation.

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