Gmapping problem

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Hello I am trying to get a map of the area with a differential drive mobile robot, for which the following are the steps followed.

1. Open the kinect with openini using "roslaunch openni_launch openni.launch".

2. Change the pointcloud to the laser scan using "rosrun depthimage_to_laserscan depthimage_to_laserscan image:=/camera/depth/image_raw", after step-2 I am able to see the "laser scan" in the RVIz properly.

3. Running the gmapping with "rosrun gmapping slam_gmapping scan:=/scan tf:=/odom" , I am running the node which publishes the odom (the odometry data from the real robot).

4. Then open rviz with "rosrun rviz rviz".

But in RVIZ I am unable to see any mapping.

Questions:

1. The procedure which I follwed is correct or Is there something I am missing..?

2. For publishing the odo data I am using the example from the following link: http://wiki.ros.org/navigation/Tutori... with the following changes:

   • Added a callback, so as to subscribe to the incoming data from the robot.
   • Changed the velocities to suit for differential drive robot.
   • Small change in calculation of the robot position based on odo.

But the odom published from this has many fields:

    nav_msgs::Odometry odom;
    odom.header.stamp = current_time;
    odom.header.frame_id = "odom";

    //set the position
    odom.pose.pose.position.x = x;
    odom.pose.pose.position.y = y;
    odom.pose.pose.position.z = 0.0;
    odom.pose.pose.orientation = odom_quat;

    //set the velocity
    odom.child_frame_id = "base_link";
    odom.twist.twist.linear.x = vx;
    odom.twist.twist.linear.y = vy;
    odom.twist.twist.angular.z = vth;

which one I should give to the gmapping...?

Please find the rqt_graph here

Please find the frames.pdf here

Many thanks in advance