The world of The Witcher 3: Wild Hunt is massive and so many times it become difficult for players to get exact location of certain element such as Power, Gwent Players and Traders that sell Gwent cards and many other things.
Reddit user Addamm, has re-created (to some extent) the world map of The Witcher 3: Wild Hunt and marked the locations of all places of power, gwent players and traders that sell gwent cards.
Additionally, Reddit user jtzako made this amazing The Witcher 3: Wild Hunt map with all the vendors, inns etc on the map. He also labeled some to make certain places easier to find. Unlabeled shops sell generic stuff.
Lastly, Reddit user EonSnake created a The Witcher 3: Wild Hunt with Places of Power in Velen marked.
Hope all these fan created map with help you out. Do let us know in the comment section below if you guys are facing any issue with the details provided in the maps above.