You can find answer here:

https://www.researchgate.net/post/Radial_power_spectrum_in_MAGMAP_Geosoft_Oasis_Montaj_Help

Isaiah Adelere: the Ahmed reference is good, but your question is following geothermal interpretation and analysis, I understand.

Therefore, you should also take into account three critical aspects:

1) the size of the grid you used, means the area/dimension of interest in your research.

2) the "type" of anomaly that you use as an input.

3) the method that your choose.

1) As all of you know, when you have a grid, you can separate the answers from the regional and residual ones' contributions. And, in my own experiences, this is a critical point. If you are interested to know, by the way, the depth of the basement, maybe it's better to try the RAPS source estimation depth from the residual anomaly. On the other hand, if you are interested to know the Curie depth interface, or maybe the deepest crustal boundaries, so, you can try with the total / regional.

2) You consider the size of the grid for RAPS solutions: the bigger, the deepest sources, even for total, regional or residual anomalies. Maybe you are using the EMAG version of the grid. I use the RAPS as a general indicator of the possible responses, how many main interfaces are there in my project, to follow the objective to convert to depth the anomaly, by SPI or AS, not to estimate the centroid to geothermal analysis. You must think about this aspect.

3) Remember about the method that you choose is the centroid spectral method, and hence you must define in the RAPS two components that represent the best-fit edges for the near and the far roots, and the depth to the bottom of the root is reached from by subtraction.

My best wishes to all of you.

Mario

Mario E. Sigismondi