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Aydin, Toprak, Baturayoglu 
Orientation and spatial distribution of the digitised features are believed to have a certain relationship with the landscape. For this 
reason, a set of analyses is carried out to define the topographic characteristics of the landscape. The ASCII text file of the 3D GPS 
data was transferred into TNTMips software. The digitised sub-surface features were also converted into TNTMips and the region, 
where the digitised sub-surface features were located, was cut out of the GPS data in order to eliminate the city wall elevations and 
topographic features. Thus, the elevation, slope and aspect maps and histograms of the area were produced (Figs. 1-3). 
To compare the sub-surface data with the topography, the elevation, slope, and aspect maps of these features were needed. However, 
the sub-surface data was in line format and it is impossible to produce a surface model from line data. Therefore, the sub-surface 
database was transferred into RockWorks99 software and the midpoint of every line was calculated as x and y and saved as an ASCII 
text file in order to convert the line data into point data. This midpoint-based sub-surface data was imported into TNTMips software; 
and elevation, slope and aspect text files of sub-surface data were generated and exported as ASCII text files in order to produce 
histograms in Microsoft Excel. The histograms of elevation, slope and aspect were divided into intervals similar in landscape 
histograms and their frequencies were calculated (Figs. 4 and 5). 
Figures 5a and 5b: The histogram of the aspect data of sub-surface 
features at 10 degree intervals (top); frequency-weighed (bottom 
left) and length-weighed (bottom right) rose diagrams of the 
directions (aspect) of sub-surface features. 
Figure 6: Rose diagrams of the sub-surface features for 
different length values (numbers refer to length in meters). 
The aspect characteristics of sub-surface data are investigated in two ways. The first one is the histogram produced from GPS data 
similar to elevation and slope. The second one is the rose diagram prepared from the coordinates of the digitised features (Fig. 6). 
Length (m) 
Figure 7: The histogram of the lengths of the sub-surface features at lm intervals.