3.3.2. Observations FileΒΆ

This file is input when forward modeling or inverting field-collected data. Using 8 columns, the observation file indexes the frequencies, transmitters and receivers used for each measurement as well as the field observations and data uncertainties. Each row defines a unique field measurement. The general format is as follows:

Note

  • Blue hyperlinked entries are values specified by the user

  • To omit a particular datum in the inversion, used the flag -99 on its corresponding uncertainty.

tx_ind \(\;\) f_ind \(\;\) rx_ind \(\;\) data_opt \(\;\) data_real \(\;\) unc_real \(\;\) data_imag \(\;\) unc_imag
tx_ind \(\;\) f_ind \(\;\) rx_ind \(\;\) data_opt \(\;\) data_real \(\;\) unc_real \(\;\) data_imag \(\;\) unc_imag
tx_ind \(\;\) f_ind \(\;\) rx_ind \(\;\) data_opt \(\;\) data_real \(\;\) unc_real \(\;\) data_imag \(\;\) unc_imag
\(\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\; \vdots\)
tx_ind \(\;\) f_ind \(\;\) rx_ind \(\;\) data_opt \(\;\) data_real \(\;\) unc_real \(\;\) data_imag \(\;\) unc_imag


Important

Due to the way the forward problem is solved, it is imperative that the user sort the observations:
  • First by transmitter

  • Next by frequency

  • Then finally by receiver

Important

The data are the dot product of the total magnetic field (\(\mathbf{H}\)) with the direction defining the dipole moment of the receiver (\(\mathbf{m}\)).

\[d = \mathbf{H} \cdot \frac{\mathbf{m}}{| \mathbf{m} |}\]

Important

The data are represented in a left-handed coordinate system where X is Easting, Y is Northing and Z +ve is downward.

Parameter Descriptions

  • tx_ind: The index corresponding to the desired transmitter within the transmitter file.

  • f_ind: The index corresponding to the desired frequency within the frequencies file.

  • rx_ind: The index corresponding to the desired receiver within the receiver file.

  • 1: As of May 2018, a flag value of 1 is entered here. In future iterations of the code, this entry may be related to additional functionality.

  • data_real: The real component of the observed data.

  • unc_real: The uncertainty for the real component of the observed data.

  • data_imag: The imaginary component of the observed data.

  • unc_imag: The uncertainty for the real component of the observed data.