3.3.1. Survey Index File¶

This file is input when forward modeling data. Using 4 columns, the observation file indexes the frequencies, transmitters and receivers used for each measurement. Each row defines a unique field measurement. The general format is as follows:

tx_ind $$\;$$ f_ind $$\;$$ rx_ind $$\;$$ data_opt
tx_ind $$\;$$ f_ind $$\;$$ rx_ind $$\;$$ data_opt
tx_ind $$\;$$ f_ind $$\;$$ rx_ind $$\;$$ data_opt
$$\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\;\; \vdots$$
tx_ind $$\;$$ f_ind $$\;$$ rx_ind $$\;$$ data_opt

Important

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

• Next by frequency