The Geophysical Survey of an Iron Age City in Central Anatolia: Kerkenes Dag 
521 
According to these decision rules, the map of each difference histogram was produced in TNTMips software. The black colour shows 
the preferred areas in accordance with elevation, slope and aspect (Fig. 11). The preferred areas in relation with elevation suggest that 
the central part of the study area has the most preferred elevation frequency. The preferred areas according to the slope difference 
histogram are randomly distributed throughout the study area, but mainly concentrated at the eastern part. The preferred areas in 
respect to aspect difference are mainly located at the western part of the study area. 
Figure 11: Preferred areas (in black) in accordance with the decision 
rules derived from the histogram differences of sub-surface features 
(top), slope (middle) and aspect (bottom).