How to use the pymavlink.mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT function in pymavlink

if type == 'MISSION_ITEM':
            try:
                while m.seq > wp.count():
                    print("Adding dummy WP %u" % wp.count())
                    wp.set(m, wp.count())
                wp.set(m, m.seq)
            except Exception:
                pass
            continue
        if type == 'CMD':
            if options.mission is None:
                m = mavutil.mavlink.MAVLink_mission_item_message(0,
                                                                0,
                                                                m.CNum,
                                                                mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT,
                                                                m.CId,
                                                                0, 1,
                                                                m.Prm1, m.Prm2, m.Prm3, m.Prm4,
                                                                m.Lat, m.Lng, m.Alt)
                try:
                    while m.seq > wp.count():
                        print("Adding dummy WP %u" % wp.count())
                        wp.set(m, wp.count())
                    wp.set(m, m.seq)
                except Exception:
                    pass
            continue
        if not mlog.check_condition(options.condition):
            continue
        if options.mode is not None and mlog.flightmode.lower() != options.mode.lower():
            continue

The waypoints are positioned to form a square of side length 2*aSize around the specified LocationGlobal (aLocation).

    The function assumes vehicle.commands matches the vehicle mission state 
    (you must have called download at least once in the session and after clearing the mission)
    """	

    cmds = vehicle.commands

    print(" Clear any existing commands")
    cmds.clear() 
    
    print(" Define/add new commands.")
    # Add new commands. The meaning/order of the parameters is documented in the Command class. 
     
    #Add MAV_CMD_NAV_TAKEOFF command. This is ignored if the vehicle is already in the air.
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_TAKEOFF, 0, 0, 0, 0, 0, 0, 0, 0, 10))

    #Define the four MAV_CMD_NAV_WAYPOINT locations and add the commands
    point1 = get_location_metres(aLocation, aSize, -aSize)
    point2 = get_location_metres(aLocation, aSize, aSize)
    point3 = get_location_metres(aLocation, -aSize, aSize)
    point4 = get_location_metres(aLocation, -aSize, -aSize)
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point1.lat, point1.lon, 11))
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point2.lat, point2.lon, 12))
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point3.lat, point3.lon, 13))
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point4.lat, point4.lon, 14))
    #add dummy waypoint "5" at point 4 (lets us know when have reached destination)
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point4.lat, point4.lon, 14))    

    print(" Upload new commands to vehicle")
    cmds.upload()

dp += self.unitVector.y * vectorToTarget.y
        dp += self.unitVector.z * vectorToTarget.z
        
        self.actualDistance = location_helpers.getDistanceFromPoints3d(self.initialLocation, self.vehicle.location.global_relative_frame)

        if (dp < 0):
            self.actualDistance = -self.actualDistance

        # We can now compare the actual vs vector distance
        self.distError = self.actualDistance - self.distance
                
        # formulate mavlink message for pos-vel controller
        posVelMsg = self.vehicle.message_factory.set_position_target_global_int_encode(
            0,       # time_boot_ms (not used)
            0, 1,    # target system, target component
            mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT,  # frame
            0b0000110111000000,  # type_mask - enable pos/vel
            int(loc.lat * 10000000),  # latitude (degrees*1.0e7)
            int(loc.lon * 10000000),  # longitude (degrees*1.0e7)
            loc.alt,  # altitude (meters)
            velVector.x, velVector.y, velVector.z,  # North, East, Down velocity (m/s)
            0, 0, 0,  # x, y, z acceleration (not used)
            0, 0)    # yaw, yaw_rate (not used)

        # send pos-vel command to vehicle
        self.vehicle.send_mavlink(posVelMsg)

def set_yaw(self, heading):
        # create the CONDITION_YAW command
        msg = self.vehicle.message_factory.mission_item_encode(0, 0,  # target system, target component
                                                     0,     # sequence
                                                     mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, # frame
                                                     mavlink.MAV_CMD_CONDITION_YAW,         # command
                                                     2, # current - set to 2 to make it a guided command
                                                     0, # auto continue
                                                     heading, 0, 0, 0, 0, 0, 0) # param 1 ~ 7
        # send command to vehicle
        self.vehicle.send_mavlink(msg)
        self.vehicle.flush()

newRoi.alt = tmp
            self.addLocation(newRoi)

        self.updateROIAlt(channels[RAW_PADDLE])

        # nothing to do if no user interaction
        if not self.needsUpdate:
            return

        # clear update flag
        self.needsUpdate = False

        # Tell Gimbal ROI Location
        msg = self.vehicle.message_factory.command_int_encode(
                    0, 1,    # target system, target component
                    mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, #frame
                    mavutil.mavlink.MAV_CMD_DO_SET_ROI, #command
                    0, #current
                    0, #autocontinue
                    0, 0, 0, 0, #params 1-4
                    self.roi.lat*1.E7,
                    self.roi.lon*1.E7,
                    self.roi.alt)

        self.vehicle.send_mavlink(msg)

# learn any changes to controller alt offset to apply it to other controllers when instantiated (to avoid jerks)
        self.followControllerAltOffset = pos.alt - self.filteredROI.alt

        # mavlink expects 10^7 integer for accuracy
        latInt = int(pos.lat * 10000000)
        lonInt = int(pos.lon * 10000000)

        # Convert from NEU to NED to send to autopilot
        vel.z *= -1

        # create the SET_POSITION_TARGET_GLOBAL_INT command
        msg = self.vehicle.message_factory.set_position_target_global_int_encode(
             0,       # time_boot_ms (not used)
             0, 1,    # target system, target component
             mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, # frame
             0b0000110111000000, # Pos Vel type_mask
             latInt, lonInt, pos.alt, # x, y, z positions
             vel.x, vel.y, vel.z, # x, y, z velocity in m/s
             0, 0, 0, # x, y, z acceleration (not used)
             0, 0)    # yaw, yaw_rate (not used)

        # send command to vehicle
        self.vehicle.send_mavlink(msg)


        ''' Pointing Control'''

        # If followState mandates that the user controls the pointing
        if self.followState == FOLLOW_FREELOOK:
            self.manualPitch(channels[THROTTLE])
            self.manualYaw(channels)

def condition_yaw(heading):
    msg = vehicle.message_factory.mission_item_encode(0, 0,  # target system, target component
            0,     # sequence
            mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, # frame
            mavutil.mavlink.MAV_CMD_CONDITION_YAW,         # command
            2, # current - set to 2 to make it a guided command
            0, # auto continue
            heading,    # param 1, yaw in degrees
            0,          # param 2, yaw speed deg/s
            1,          # param 3, direction -1 ccw, 1 cw
            0,          # param 4, relative offset 1, absolute angle 0
            0, 0, 0)    # param 5 ~ 7 not used
    # send command to vehicle
    vehicle.send_mavlink(msg)
    vehicle.flush()

print(" Define/add new commands.")
    # Add new commands. The meaning/order of the parameters is documented in the Command class. 
     
    #Add MAV_CMD_NAV_TAKEOFF command. This is ignored if the vehicle is already in the air.
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_TAKEOFF, 0, 0, 0, 0, 0, 0, 0, 0, 10))

    #Define the four MAV_CMD_NAV_WAYPOINT locations and add the commands
    point1 = get_location_metres(aLocation, aSize, -aSize)
    point2 = get_location_metres(aLocation, aSize, aSize)
    point3 = get_location_metres(aLocation, -aSize, aSize)
    point4 = get_location_metres(aLocation, -aSize, -aSize)
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point1.lat, point1.lon, 11))
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point2.lat, point2.lon, 12))
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point3.lat, point3.lon, 13))
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point4.lat, point4.lon, 14))
    #add dummy waypoint "5" at point 4 (lets us know when have reached destination)
    cmds.add(Command( 0, 0, 0, mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT, mavutil.mavlink.MAV_CMD_NAV_WAYPOINT, 0, 0, 0, 0, 0, 0, point4.lat, point4.lon, 14))    

    print(" Upload new commands to vehicle")
    cmds.upload()

cmds.wait_ready()


cmds = vehicle.commands
cmds.clear()
for pt in messages:
    #print "Point: %d %d" % (pt.lat, pt.lon,)
    lat = pt.lat
    lon = pt.lon
    # To prevent accidents we don't trust the altitude in the original flight, instead
    # we just put in a conservative cruising altitude.
    altitude = 30.0
    cmd = Command( 0,
                   0,
                   0,
                   mavutil.mavlink.MAV_FRAME_GLOBAL_RELATIVE_ALT,
                   mavutil.mavlink.MAV_CMD_NAV_WAYPOINT,
                   0, 0, 0, 0, 0, 0,
                   lat/1.0e7, lon/1.0e7, altitude)
    cmds.add(cmd)

#Upload clear message and command messages to vehicle.
print("Uploading %d waypoints to vehicle..." % len(messages))
cmds.upload()

print("Arm and Takeoff")
arm_and_takeoff(30)


print("Starting mission")

# Reset mission set to first (0) waypoint