Specify Magnetic Anomaly

In GM-SYS Profile Modelling, a "Station" is a location at which an anomaly component is calculated and optionally, was measured. Use the Specify Magnetic Anomaly dialog to define the locations of magnetic calculations, the observed values, as well as the Earth's field parameters appropriate to your survey. The Earth's field parameters must be correctly defined to calculate the model response properly.

If Magnetic Gradient calculations are enabled, you may also import observed magnetic gradient components measured at the same locations.

In order for GM-SYS Profile Modelling to calculate a response at a location, the X, Y, and Z coordinates of the station must be specified. However, observed values are not required. You may import data from a Geosoft Database line, from an ASCII file, or you may create equally-spaced calculation stations with no observed values. In all cases, specifying new magnetic stations will completely replace any existing magnetic stations (including gradients).

Select Import from database line if you have X, Y, Elevation, and optionally Observed Magnetic Anomaly channels in a Geosoft Database line. If you have the four data fields in a flat ASCII file, select Import from text file. Select Create equally-spaced stations if you do have observations, but wish to calculate the response of the model. Selecting a radio button will launch a separate dialog specific to your selection. In each of these cases, you may also import observed magnetic gradient components if Magnetic Gradient calculations are enabled

Specify a background susceptibility if your observed data have been corrected using a background value. In most cases, the correct value is "0.0".

Specify the Earth's field parameters appropriate to your survey. If you know the location of the survey and the date it was flown, you may calculate reasonable values for the Earth's field parameters by selecting Calculate. Once you have calculated the field values, closing the IGRFPT dialog will load the values into GM-SYS Profile Modelling.