Mapping and monitoring of the land use/cover changes in the wider area of Itanos, Crete, using very high resolution EO imagery with specific interest in archaeological sites

摘要

Archaeological site mapping is important for both understanding the history and protecting the sites from excavation during developmental activities. As archaeological sites are generally spread over a large area, use of high spatial resolution remote sensing imagery is becoming increasingly applicable in the world. The main objective of this study is to map the land cover of the Itanos area of Crete and of its changes, with specific focus on the detection of the landscape's archaeological features. Six satellite images were acquired from the Pleiades and WorldView-2 satellites over a period of 3 years. In addition, digital imagery of two known archaeological sites was used for validation. An object-based image analysis classification was subsequently developed using the five acquired satellite images. Two rule sets were created, one using the standard four bands which both satellites have and another for the two WorldView-2 images with their four extra bands included. Validation of the thematic maps produced from the classification scenarios confirmed a difference in accuracy amongst the five images. Comparing the results of a 4-band rule set versus the 8-band rule set showed a slight increase in classification accuracy using extra bands. The resultant classifications showed a good level of accuracy exceeding 70%. Yet, separating the archaeological sites from the open spaces with little or no vegetation proved to be challenging. This was mainly due to the high spectral similarity between rocks and the archaeological ruins. The high resolution of the satellite data allowed for the accuracy in defining larger archaeological sites, but still there was difficulty in distinguishing smaller areas of interest. The digital image data provided a very good 3D representation for the archaeological sites, assisting as well as in validating the satellite-derived classification maps. To conclude, our study provides further evidence that use of high resolution imagery may allow for archaeological sites to be located, but only where the archaelogical features are of an adequate size.