Artikel 43

1. In the fields of meteorology, geodesy, topography, hydrography and cartography, the authorities of a force and the German authorities shall communicate to each other information on all matters of importance for the common defence and shall exchange all data necessary for this purpose.
2. The authorities of a force may, after timely notification to the German authorities, make topographic, geodetic, hydrographic or engineering surveys or reconnaissances in the interest of the common defence if special reasons of security or secrecy necessitate this or if the German authorities are unable to carry out such projects to the extent or within the time required. Representatives of the German authorities may be present, unless prohibited by special reasons of secrecy, while any such survey is being made. The German authorities shall, when necessary, use their powers under German law in order to obtain authority for representatives of the force to enter property.