# 3.3.2. Observations File¶

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

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.