Imgrad n'Tayaline rock art data
The corpus of rock art Imgrad n'Tayalin is a project that was launched as part of a doctoral thesis at the University Cadi Ayyad, with a dual purpose. On the one hand, in the field of research, a rigorous documentary base has been put in place, which has made it possible to develop a global study, thus reducing the margin of error resulting from the subjective perceptions concerning them. On the other hand, in the heritage field, it was a poorly structured, inaccessible and little known collection, but of considerable national and international importance, particularly in the context of the draft proposal for classification as as world heritage of pseudo-bovidian rocks. Art.
Steps to reproduce
In order to process images, computer-assisted survey is a method of producing drawings and layers from photographs using appropriate computer graphics software (Adobe Illustrator and Photoshop). As a result, the stylus and the graphic tablet replace the pencil and other levator instruments. The main function of the image processing software is to make it possible to see the color contrasts between the surface of the rock and its patina which is the feature of the engraving. Thus, we drew by hand all the pixels that correspond to the color of the patina while using a color scheme to differentiate the independent elements of the same engraving. This method is probably perfectible and it is very slow. Which, given the number of engravings to be taken in the rock sites, would require more than 5 years of work. It is therefore a question of making visible elements that already existed in the image, but which were sometimes barely perceptible or even invisible to the naked eye. In order to evaluate the residual share of subjectivity with the image enhancement for these extreme cases, we carried out two parallel studies, one consisting in performing the reading of the same figure several months apart, the other based on the comparison of the statements of the same figure by several people familiar with Illustrator and Photoshop software.