It also indicated that aerial imagery of these same areas was either limited or generally kept secret by the respective conflicting parties. As a result, the selected set of islands was revised to accommodate the limited archive of suitable images of the study area. Table 2 and Figure 2 show the revised set of islands that were ultimately analyzed with aerial and commercial satellite imagery. Each island was selected by considering its relative size and significance along with the availability of archived images. Preference was given to islands imaged by commercial satellite platforms because this particular technology has not been tested for South China Sea monitoring.
Aerial photos indicate that China constructed several octagonal structures on the reef.
Philippines, Taiwan, and Vietnam also have claims to the reef. The island reportedly has an airstrip, lighthouse, and power plant. 24 China, Taiwan, and Vietnam also have claims to the island. E Located approximately 26 km SW of Thitu Island, this island reportedly has a blockhouse, supply platform, helicopter parking apron, and 100 Watt HTIW412 radio communicator. A Chinese garrison force reportedly occupies the reef.