## 5 Results and Discussion
### Satellite Spectral Analysis
#### 5.2.2 Spectral Analysis of Iron Oxide  
By using the WV-II index, large sections of the ancient city's known temple enclosure wall were identified (Figure 9). This mudbrick wall, which is over 14 m wide and 2000 m long, once encircled the sacred temple precinct of the ancient city. Originally constructed during Dynasty 19, the monumental enclosure was later enlarged in Dynasty 30 [31]. This expansion is supported by an inscription of [PERSON] on a stela found at the site, which details the enlargement of the mudbrick wall as well as the whole sacred complex within the wall [33]. While the full extent of the Dynasty 30 wall has been mostly identified by archaeological work from previous excavations, the WV-II image was able to recognize it rapidly and clearly. In the derived WV-II image, the 14 m wide wall displays high WV-II values, demonstrating medium to high iron oxide content (Figure 9). The on-ground validation of the wall by other missions is important in that it confirms the effectiveness of remote sensing, especially the use of mineral indices, for archaeological prospection. Additionally, through the use of the WV-II index, a clearly delineated structure (named \"Installation G\") located directly underneath the east-west Antinoe Street was uncovered (Figure 9). Installation G is approximately 20 by 24 m and has well-defined north, east, and west walls. Found in the interior are void-like areas, which may have been rooms or chambers. In the final WV-II image, the outline of the structure exhibits much lower WV-II index values (\(\sim\)0.44) than the surrounding area, which indicates the low content or absence of iron oxide. Unlike the enclosure wall, which was mapped due to the high levels of iron-oxide detected, Installation G was identified because of its low levels of the compound. This is an instance in which the patterns of absence (versus just presence) are as effective in the detection of a hidden feature. It should be noted that the walls of Installation G are most likely constructed out of mudbrick, even though it appears to be negative for iron oxide. Segments of the structure appear in two different indices, the IPVI and WV-II. In IPVI, the walls can be delineated due to the lush, healthy vegetation growing atop it, which is indicative of a mudbrick construction. On the other hand, in WV-II, due to the obscurement of the high vegetation coverage, the analysis shows a very low component of iron oxide--a negative signal versus the surrounding area. While conclusions on the function or purpose of this installation cannot be made merely through the use of remote sensing analysis, two architecturally similar structures to Installation G can be found at Tell el-Balamun (northeastern Nile Delta; Figure 10). The two structures at Tell el-Balamun were identified as Saite period casemate-type buildings (one very large and one smaller) with numerous chambers compacted between thick divisions/walls [58; 59]. Traditionally, casemate foundations usually have numerous chambers or cells that are filled with sand, earth, brick, or rubble [60]. It is important to mention a theory that the casemate structures at Tell el-Balamun were, in fact, military forts used  
Figure 9: WorldView New Iron Index (WV-II) for the entire study area with the detected site highlighted in the white box. The WV-II-identified lower section of the city’s known mudbrick enclosure wall is also highlighted in white. The detection of this wall is due to the presence of mid to high iron oxide content (**A**). WV-3 true color image showing the area covered by surface vegetation (**B**). Installation G revealed by very low WV-II content (**C**). Linear feature visible using edge-detection spatial filtering (**D**). WV-II overlaid onto the edge detection in order to accentuate the buried linear structure (**E**). during the Saite Period (664-525 BCE), but for now this is simply speculation [58].