## 3 Technical Features and Socio-Legal Characteristics of Africa's Satellite Constellation
### Discovery of Relict Boundaries through Satellite Imagery  
The connection between delimitation and demarcation tasks on one hand and archaeological and heritage sites on the other can and often come into sharp focus in Africa as much as elsewhere. This is because heritage sites along with other significant natural features quite often become adapted as marks of boundary alignment. One of the classic rendition of this problem in international relations is to be found however, in the notorious dispute between Cambodia and Thailand over the religious and heritage sites of the Temple of Preah Vihear. This dispute has been adjudicated upon by the ICJ [79]. Despite the existence of a definitive judgment unfortunately, severe problems periodically flare up as a result of religious and cultural implications on the affected population. The _Temple of Preah Vihear case_ concerned a boundary conflict between Cambodia and Thailand (formerly known as Siam). The disputed area contained an old temple of great cultural significance. It had been built by the Khmer Peoples, the ancestors of the present Cambodian population, at the high point of their power; although since then the Khmer People have been forced back into smaller areas. The considerations the parties wished the Court to pronounce upon included: to which of the two countries' history is the temple more related. Despite the Court's decision in 1962 conflict persist between the parties in relation to the temple and border skirmishes occurred as recent as 2008 [80; 81]. Relict boundaries refer to antecedent boundaries which have been abandoned for political purposes but are still evident in the cultural landscape. Relict boundaries manifest themselves in space by, among other features, direct border remains such as border stones, mounds, ancient walls, border roads, clearings, customs houses and watch-towers [82; 83; 84]. It is fortunate that evidence emanating from satellite imagery and orthorectified imagery as well as archaeological studies is providing overwhelming evidence of very precise boundary features and markers separating pre-colonial African political groups. Only a handful of the 10,000 walls and relict features discovered all over Africa have been surveyed so far. This portrays immense opportunities for geoscientific ground investigation well into the future. Fulfilling those tasks will be particularly fulfilling both from a scientific and socioeconomic point of view. Both old aerial photographs and other more modern remote-sensing methodologies like Lidar technology, LIDAR--Light Detection and Ranging--is a remote sensing method used to examine the surface of the Earth\" [85] continue to offer an opportunity to record much of this evidence all over Africa. The Kano City walls (a 24 km long, 20 m high perimeter) were considered the most impressive monument in West Africa as of 1903 but that achievement now pales into absolute insignificance in comparison with other recent discoveries of older demarcated boundaries [6]. Of particular note are the following:  
1. The 160 km long Sungbo's Eredo wall;
2. The fieldwork surveys and inspections that have revealed 1600 km of the 16,000 km long Benin earthwork complex;
3. The 45 km long Orile Owu walls;
4. Walls of Old Oyo;
5. Old Egbe wall and walls completely surrounding pre-European-influence cities of Kwiambana, Old Ningi, Gogoram, Pauwa, Old Rano, Old Sumaila [86; 87; 88; 89; 90];
6. The emerging picture is that since at least the 8 th Century AD enormous systems of walls and ditches have been used to demarcate state territorial control in the areas of contemporary Benin and Western Nigeria. These walls are heritage sites of immense cultural and touristic value and the ignorance of their existence is being removed by rediscoveries through space activities. Eredo for instance represents a system of walls and ditches dug in laterite, a typical African soil consisting of clay and iron oxides. The total length of these fortifications is approximately 160 km.