Add id to raw data in an array
I would suggest:


Use a library (TinyGPS++ for example) to read the GPS data and extract just what you want.
Use a struct to craft a packet that you can send over bluetooth, or send the data as a textual representation, depending on your needs.


For a struct you can:

struct packet {
    uint8_t id;
    float latitude;
    float longitude;
};

struct packet myPacket;
myPacket.id = 32; // Unique ID
myPacket.latitude = gps.getLatitude(); // Whatever function call here
myPacket.longitude = gps.getLongitude(); // or whatever
rf95.send((uint8_t *)&amp;myPacket, sizeof(struct packet));