THE USE OF SATELLITE IMAGES IN PREPARATION FOR THE ESTABLISHMENT OF INTERNATIONAL BOUNDARIES

Within the stage of boundary creation and drafting of border treaties or agreements, the boundary engineer is serving as technical adviser to the negotiator (statesmen, lawyer, politician,) of the treaty or the agreement. One essential tool of the boundary engineer is the use of satellite images which would serve as an illustration and sometimes update of the real situation on the ground. Satellite images can be an essential resource at the negotiating table and revise existing maps or serve as map substitutes in poorly or even non mapped areas. In this case however annotated images should be used and may be extremely helpful. In addition recent satellite data contains much information missing from the maps or other descriptive materials, such as details of agricultural activities, density of trees, existance and course of waters, temporary structures, such as ditches and fences, destroyed buildings, or even dismantled roads, which would serve as prove of sovereignty during negotiations and decision making and the writing of the treaty or agreement between countries involved.

Satellites images are also one of the best means to ensure that the decisions of negotiators are transformed to the ground in the demarcation and delineation stages.
This paper will reflect to the practical experiences which have been made in writing and implementation of the international boundary treaty between the Kingdom of Saudi Arabia and the Republic of Yemen. The work shown here will focus on the use of rectified satellite images in the delimitation stage, for reconnaissance tasks (office and field), and the production of “fly through’s” for the border area. The latter proved as very useful. During the negotiations and decision making they could be used as confining tools, supporting the formulations in the writing of the treaty, like adding some clauses on the modification of the border line, when it passes through villages. Further essential applications of satellite data concentrated in survey demarcation and delineation tasks, photo control planning and map production of the unmapped areas of the treaty. A small scale mapping was agreed upon for regions outside the area covered by aerial photography. Quite a number of factors effect the considerations to use the satellite imagery in the large scale boundary mapping such as the size of the area, its topography and environment, the technical characteristics of the final product and its accuracy limitations, the availability of image data and last not least the cost of the data required .In conclusion the principal advantage of satellite images in international boundary application tasks is their availability on a commercial basis without the well known problem of getting authorization in over- flying certain territories or censorship of any kind. Examples will be shown that demonstrate the importance of such tools bringing the terrain to the negotiating table and enabling the enhancement of existing GIS, maps or map substitutes in poorly or unmapped areas.