Ask HN: Crowdsourcing a Map in Rural Africa

Hi HN! I am asking for your guidance again. The problem: In Subsaharan Africa, maps are unreliable and/or unavailable. Excluding city centers, there are no addresses, street names or the likes. The context: I was shocked by the smartphone penetration. Everyone has at least one smartphone with GPS/Camera and Whatsapp/email (Thanks India & China). The 4g/LTE service is reliable & cheap. The idea: With a relatively young population and a low cost of living, I can afford to pay people to crowdsource streets, homes, shops, etc... Thus I am building an android app for that. Taking a picture of every door you see Mapping roads with the user GPS Adding elements such as road condition/infrastructure The question: How would you advise me to build such a service? Should I ask the user to open the app while he is moving, and taking pictures of every door he sees? Then add it to a map? How can I generate an accurate map from hundreds of user travel histories and geo-tagged pictures? I'm gladly receiving every piece of advice My knowledge: I owned mobility as a service Saas B2G company in rural Canada called Proxybus. I have worked with OSM (OpenStreetMaps), and I'm a fairly skilled full-stack developer.