## 3 Technical Features and Socio-Legal Characteristics of Africa's Satellite Constellation
### Earth Observation and Remote Sensing in the Maritime Sectors  
The work of the parties in the maritime sector exposed a current legal problem which will perhaps continue to emerge in these sort of processes. The question is how to deal with maritime maps used for delimitation of territory that were made before geospatial data was available. The positionsderived from satellite navigation systems such as Global Positioning Systems (GPS) are based on World Geodetic System (WGS) 1984 Datum, The WGS 84 may be described as an Earth-centred, Earth-fixed terrestrial reference system and geodetic datum. This system is based on a consistent set of constants and model parameters that describe the Earth's size, shape, and gravity and geomagnetic fields. It is also is the standard U.S. Department of Defense definition of a global reference system for geospatial information as well as the reference system for the Global Positioning System (GPS). WGS 84 is indeed compatible with the International Terrestrial Reference System (ITRS) [66]. The differences between satellite derived positions and positions on older charts and maritime maps that states may have inherited as boundary positions from their ex colonisers may be significant to navigation let alone being relied upon as accurate measurement of modern boundaries. The maritime boundaries of Africa were also largely drawn up before the availability of modern space based mapping techniques and before the ubiquitous use of the GIS. In this way the ready availability of geospatial products may open up a new set of controversies in international relations. A controversy erupted early in the Cameroon-Nigeria negotiations as to how the World Court arrived at the delimitation it decided upon in the maritime sector. This is because the treaties it utilised in the judgment which mentioned features and positions were drawn up prior to the introduction of the GIS System. Thus, how did the Court approved delimitation interface with the GIS based system? Specifically which system did the Court rely on behind doors during its deliberations and while considering its ruling. The judgment itself was silent on its reliance on non-reliance upon any available geospatial data. Indeed it became clear that the maritime coordinates on the available charts were not in terms of WGS 84. The task of conversion was also compounded because a certain crucial Map-Chart 3433 which was relied upon by the Court had no horizontal reference datum. As a result there was no computational way of deriving a correction factor converting the coordinates from the chart to WGS 84. An Expert Determination procedure was incorporated into the negotiations which witnessed the appointment of a former Surveyor General of New Zealand to look into the facts. He concluded that: \"If the current coordinates are assumed to be WGS84 coordinates, without any conversion, when they are reproduced on the sea or inlet they will not be at the exact position intended by the Parties or the ICJ... \" (Report of [PERSON] annexed to Report of the Third meeting (2005) held on file by author.) Difficult compromises had to be made to resolve the scientific ambiguities which involved establishing new points using GPS receivers. First the conversion of coordinates to WGS84 datum was achieved through surveying the position of a minimum of 20 identifiable reference points above the surface of the sea on either side of the maritime boundary, which have been previously identified by mutual agreement on the Admiralty Chart 3433 mentioned in the ICJ judgment. Second, where certain features cannot be identified at the location, other physical features above the surface of the sea which appear on the Admiralty Chart 3433 were surveyed to ensure that an adequate number of points had been surveyed for geo-referencing purposes, See Annex III Terms of Reference and Modalities for the Delineation of the Maritime Boundary in Report of the Fifth Meeting (2006).