## 1 Introduction  
Throughout the MENA (Middle East and North Africa) region, many ancient sites currently lie concealed beneath dense sand, vegetation growth, and a shifting anthropogenic landscape (e.g., agricultural fields and urban pockets). It is due to these environmental factors that the exact location and/or full spatial extent of many archaeological sites around the region remain largely undiscovered. While in most cases the use of traditional on-ground investigations (e.g., archaeological excavations) have proven ineffective for quickly detecting such unknown sites, earth observation data has recently emerged as an unparalleled tool [1, 2, 3]. The rapid and widespread discovery of these previously undetected cultural heritage sites is not only important from an intellectual standpoint, as archaeologists can better piece together information about past societies, but it is also crucial for ensuring the safety of such vulnerable areas. In other words, it is simply impossible to protect what one does not know exists. As such, the use of high-resolution satellite imagery has permitted cultural resource managers, policy holders, and urban planners, among others, to record, evaluate, manage, and mitigate any environmental or man-made threats to these areas before their possible destruction [4]. The application of remote sensing techniques for the exploration of archaeological sites worldwide has facilitated the rapid (digital) preservation of highly threatened and vulnerable areas [5; 6; 7; 8]. Since the declassification of various imaging reconnaissance satellites (e.g., CORONA and U2), as well as the advent of high-resolution spaceborne satellite data (e.g., QuickBird, WorldView, and Pleiades), archaeologists have been able to successfully locate, identify, and digitally preserve thousands of cultural heritage sites [9; 10; 11; 12]. The utilization of these temporally continuous satellite images, especially multispectral data, to investigate archaeological locations has proven to be increasingly effective because large spatial extents can now be captured and analyzed at unprecedented speeds and accuracies. Furthermore, as satellite data is both non-invasive and non-destructive, it is possible to analyze a site safely from thousands of miles above the Earth's surface, no matter how geographically or politically inaccessible the study area is [13]. In fact, not only does one not have to step foot on the site itself, but most importantly, there is little to no disturbance or destruction to the archaeological area--a crucial component in the mission to safeguard these endangered places. A particularly useful application of remote sensing for archaeological prospection comes in the form of assessing localized soil and vegetation changes across a site [14]. A series of spectral-enhancement indices, such as the Normalized Difference Vegetation Index (NDVI) and the Green Normalized Difference Vegetation Index (GNDVI), are often applied to multispectral satellite imagery to measure the quantity and quality of photosynthetic material in green vegetation [15; 16]. From the use of such indices, vegetation marks known as \"cropmarks\" can be identified. These cropmarks form as a result of the differential growth and health of arable plants overlaying near-surface archaeological features [17]. As buried archaeological structures can impact the growth rate of crops in the soil above them, a distinctive pattern between the healthy (above undisturbed soil) and stressed (above an archaeological structure) vegetation starts to become apparent. For example, previous studies in Europe have been able to identify many Roman-period ruins, such as Roman forts, transitory camps, and roadways, through the detection of such cropmarks [18]. Similarly, recent projects in the Nile Delta (Egypt) have also uncovered settlement mounds and ancient river courses using vegetation analysis [19].