1. Ardhi University, School of Geospatial Sciences and Technology Dar es Salaam Tanzania
2. Also at Department of Earth, Atmospheric and Planetary Sciences Purdue University West Lafayette Indiana USA
3. Ecole Normale Supérieure, Department of Geosciences Paris France
4. Institut National de l'Information Géographique et Forestière (IGN) LAREG, Marne‐la‐Vallée France
5. Institut National de l'Information Géographique et Forestière (IGN), Direction Technique Saint Mandé France
6. Univ Paris Diderot, Sorbonne Paris Cité, Institut de Physique du Globe de Paris Paris France
7. Regional Center for Mapping of Resources for Development (RCMRD) Nairobi Kenya