Need More Input's profile - activity

answering my own question 2) : it turns out that it -is- possible to hard-set the location and orientation of the turtle. This can be accomplished by issuing the following command:

$ rosservice call /turtle1/teleport_absolute -- [X] [Y] [theta]

where [X],[Y], and [theta] are float numbers.

For example:

$ rosservice call /turtle1/teleport_absolute -- 0.0 0.0 90.0

puts the turtle in the lower left corner pointed upward.

When I execute

~$ rosrun turtlesim turtlesim_node

an empty blue "TurtleSim" simulation window pops up and the following messages are issued:

$ rosrun turtlesim turtlesim_node
QGtkStyle was unable to detect the current GTK+ theme.
[ INFO] [1335558676.993640551]: Starting turtlesim with node name /turtlesim
[ INFO] [1335558677.369623672]: Spawning turtle [turtle1] at x=[inf], y=[inf], theta=[0.000000]

Question 1 (of 2): Why is turtle1 spawned at a location beyond the end of the universe, instead of at its origin [0,0] ?

I executed

~$ rosrun turtlesim turtle_teleop_key

to see if the [x,y] coordinates would change when the up/down arrow keys were pressed, but unfortunately this is not the case. The [theta] value however -does- respond when the left/right arrow keys are pressed.

Output of the /turtle1/command_velocity topic:

$ rostopic echo /turtle1/command_velocity
linear: 2.0
angular: 0.0
---
linear: -2.0
angular: 0.0
---
linear: 0.0
angular: 2.0
---
...

Output of the /turtle1/pose topic:

...
---
x: inf
y: nan
theta: -3.06081461906
linear_velocity: 0.0
angular_velocity: 2.0
---
x: inf
y: nan
theta: -3.02881479263
linear_velocity: 0.0
angular_velocity: 2.0
---
x: inf
y: nan
theta: -2.99681472778
linear_velocity: 0.0
angular_velocity: 2.0
---
...

Question 2 (of 2): Is there perhaps a way to hard-set the [x,y] location ? E.g. something in the line of a command like "set turtle_pos=[0,0]" ?

I'm new in the world of ROS and have just installed ROS (Fuerte). I'm trying to make my way through the tutorial steps, but I'm encountering some problems. When I execute 'rosmake beginner_tutorials' in step 4 (1.2.1. Using rosmake) I get the following messages:

[rosmake-0] Starting >>> std_msgs [ make ]                                                                                   
[rosmake-0] Finished <<< std_msgs ROS_NOBUILD in package std_msgs
 No Makefile in package std_msgs                           
[rosmake-0] Starting >>> roslang [ make ]                                                                                    
[rosmake-0] Finished <<< roslang ROS_NOBUILD in package roslang
 No Makefile in package roslang                              
[rosmake-0] Starting >>> rospy [ make ]                                                                                      
[rosmake-0] Finished <<< rospy ROS_NOBUILD in package rospy
 No Makefile in package rospy                                    
[rosmake-0] Starting >>> roscpp [ make ]                                                                                     
[rosmake-0] Finished <<< roscpp ROS_NOBUILD in package roscpp
 No Makefile in package roscpp                                 
[rosmake-0] Starting >>> beginner_tutorials [ make ]

The building process completes quickly and reports 0 failures.

The above messages and the short building time are not what I expected based on the tutorial information.

What is going wrong here ?