Yes, WikiCamps will need to be re-purchased as you are changing, or adding, an operating system.
Different app stores (the Google Play Store and Apple App Store) do not allow cross-platform transfers.
Once downloaded, if you already have a WikiCamps User Account, you can log in with those details to access your previously saved trips and favourites.
WikiCamps. By campers, for campers.
Article relates to Android and Apple devices