HI, i am mobile and web application developer, i can do easily this job, i did this work before, here is the plan for your app. i will develop the web admin panel for you, where you can add / edit the coordinates , and these are updates on database, and the app is requested to server with searching criteria for coordinates, and app will show these coordinates with markers on map. it is the simple app,
here is the sample app, in which i used map api before
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if you required another demo, i will provide it to you, please contact me for more detail discussion and plan.