This project is solution of Geotagging Space and Aviation (Nasa Space Apps Challenge) https://2016.spaceappschallenge.org/challenges/earth/geotagging-space-and-aviation/projects/geochallenger-knowledge-through-adventure
Server is inmplement on asp.net web api, combination of fulltext search and spatial search is implemented on Elasticsearch.
Client is implement on the android, see https://github.com/GAnatoliy/geochallenger-android