A method for determining moisture values (F1; F2) in a ground area (BA2; BR), which is located between a first position and a second position, comprising: - sending an electromagnetic signal at the first position by means of a transmitting device (1; 41) such that it propagates as a ground wave; - receiving the electromagnetic signal at the second position by means of a receiving device (3; 42), characterized by - determining a value of at least two physical properties of the electromagnetic signal, namely a phase value (PH1; PH2) of the received electromagnetic signal, and a value of an amplitude of a field of the electromagnetic signal; - determining moisture values (F1; F2) of the ground area (BA2; BR) using the values of the physical properties; wherein - the ground area (BA2; BR) has a plurality of subareas (TBA1, TBA2), which are arranged one behind the other with respect to a direct connecting line of the first position with the second position extending along the ground surface of the ground area (BA2; BR), - based on a model of the ground area (BA2; BR), which describes at least one electrical physical variable of the subareas (TBA1, TBA2) as a function of the at least two physical properties of the electromagnetic signal at the second position, the moisture value (F1; F2) of the plurality of subareas (TBA1, TBA2) of the ground area (BA2; BR) is determined respectively, wherein on the basis of the model for the subareas (TBA1, TBA2) an initial value of the at least one electrical physical variable for each of the subareas (TBA1, TBA2) is determined respectively, taking into consideration properties of the respective soil in the subareas (TBA1, TBA2), wherein the model is adapted to the determined values of the at least two physical properties of the electromagnetic signal received in the second position by changing the initial values, and wherein the moisture values (F1; F2) of the plurality of subareas (TBA1, TBA2) of the ground area (BA2; BR) are determined based on the adapted model. - sending an electromagnetic signal at the first position by means of a transmitting device (1; 41) such that it propagates as a ground wave; - receiving the electromagnetic signal at the second position by means of a receiving device (3; 42), characterized by - determining a value of at least two physical properties of the electromagnetic signal, namely a phase value (PH1; PH2) of the received electromagnetic signal, and a value of an amplitude of a field of the electromagnetic signal; - determining moisture values (F1; F2) of the ground area (BA2; BR) using the values of the physical properties; wherein - the ground area (BA2; BR) has a plurality of subareas (TBA1, TBA2), which are arranged one behind the other with respect to a direct connecting line of the first position with the second position extending along the ground surface of the ground area (BA2; BR), - based on a model of the ground area (BA2; BR), which describes at least one electrical physical variable of the subareas (TBA1, TBA2) as a function of the at least two physical properties of the electromagnetic signal at the second position, the moisture value (F1; F2) of the plurality of subareas (TBA1, TBA2) of the ground area (BA2; BR) is determined respectively, on the basis of the model for the subareas (TBA1, TBA2) an initial value of the at least one electrical physical variable for each of the subareas (TBA1, TBA2) is determined respectively, taking into consideration properties of the respective soil in the subareas (TBA1, TBA2), wherein the model is adapted to the determined values of the at least two physical properties of the electromagnetic signal received in the second position by changing the initial values, and wherein the moisture values (F1; F2) of the plurality of subareas (TBA1, TBA2) of the ground area (BA2; BR) are determined based on the adapted model.