This paper presents the results of a magnetic survey on the Hellenistic and Roman site of Doura-Europos in Syria. The interpretation of the magnetic data is based on an original approach by considering the use of space in a domestic unit. This type of study has been developed for sociological research but is adapted to the information carried within geophysical data. After a brief presentation of the role of geophysical methods for the study of city planning, the most important components of the 'space syntax' will be presented and applied to two blocks of Doura-Europos, one that has been excavated in the twentieth century by the Yale University and another surveyed using the magnetic method.Key words: magnetic survey; city planning; domestic unit; space syntax; Doura-Europos; ancient Near East Si tu ne sais pas répondre à la question posée, demande toi si tu ne peux pas répondre a` une autre question qu'on a oublié de te poser (If you cannot answer a question, ask yourself whether you are able to answer another question they forgot to ask you) (Hesse, 1999)

Magnetic and electromagnetic measurements are influenced by magnetic susceptibility and, thus, are widely used in geophysical surveys for archeology or pedology. To date, the data inversion is performed separately. A filtering process incorporating both types of data is presented here. After testing the algorithm with synthetic data, the algorithm is used in several case studies in archeological prospecting. This approach presents two advantages: establishing the presence of remanent magnetizations (viscous or thermoremanent), and achieving more refined depth analysis of the anomaly.

Electromagnetic susceptibility surveys are valuable for archaeological prospection owing to their ability to cover large areas of land. Their use, however, is often compromised by the conductivity influence of the soil and the limited investigation depth of the susceptibility response. To examine these constraints further, we compared the characteristics of two types of apparatus: coincident loop (e.g. Bartington MS2 field coil) and 'Slingram' instruments (EM38, SH3, CS60 and CS150).Theoretical considerations suggest that in contrast to coincident loop apparatus, Slingram instruments are less influenced by the soil conductivity and offer a greater maximum depth of investigation. The experimental results presented in this paper collected over an artificial structure at the Centre de Recherches Gé ophysiques (CRG) of Garchy (France), confirm the theoretical results and indicate that Slingram instruments are preferable for field susceptibility measurements.

Electromagnetic induction instruments (also called loop–loop, dipole–dipole, or Slingram) are now commonly used in archaeological prospecting. They are truly light instruments, which are able to measure both the apparent electrical conductivity and the apparent magnetic susceptibility of the ground. During a field test in Bahrain Island where the soil has a high clay content and a high salt content, surprisingly high values of in‐phase response were obtained at all inter‐coil spacings using CMD “Mini‐Explorer” (GF Instruments Ltd., Brno, Czech Republic) at 30 kHz, in both horizontal coplanar and vertical coplanar configurations, and the horizontal coplanar and vertical coplanar susceptibility variations were in total opposition. This apparent discrepancy is explained by considering the in‐phase responses to be dominated by the relative dielectric permittivity. Using the raw and in‐phase vertical coplanar and horizontal coplanar data, it is possible to determine and map the apparent permittivity and apparent magnetic susceptibility. For this case of slated soils with high clay content, the relative permittivity is strong but in agreement with both experimental data at lower frequencies and theoretical models reported in the literature.