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2021-05-15 06:01:12 -0500 received badge  Student (source)
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2017-08-27 11:31:01 -0500 asked a question Turtlebot Transforms Error

Turtlebot Transforms Error I am working with the Turtlebot 2.0 and am just running the robot_with_tf.launch file provide

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2016-06-21 09:08:40 -0500 asked a question Changing subscriber topic

I have three different objects that all have their own topic of /path_finished, so at any time there is /obj1/path_finished, /obj2/path_finished, and /obj3/path_finished. I want to only subscribe to the topic when my code is assessing a certain object. I have these three objects in a list, so as I iterate through each object, I want the subscriber to subscribe to the topic name relating to that object. Is there an elegant way to do this with only one subscriber or do I just have to have three different subscribers?

Here is code below to illustrate my question:

self.path_name = ""
self.pub_wpt_queue_done = rospy.Subscriber(self.path_name, QuadWaypointQueueComplete, self.isFinished, queue_size=100)

def isFinished(self, wpt_done_msg):
    self.isFinished = veh_list_msg.is_queue_complete

def managerLoop(self,event):
    for veh_name in self.ducky_dict.keys():
        cur_ducky = self.ducky_dict[veh_name]
        self.path_name = "/"+cur_ducky+"/path_finished"
        if (self.isFinished): 
            rospy.loginfo("[%s][managerLoop] Successfully finished wpt, going to next wpt if available." %(cur_ducky.veh_name))

Any help is much appreciated, thanks!

2016-06-13 09:42:52 -0500 commented answer RVIZ not visualizing all markers

This fixed it, thank you!

2016-06-13 09:30:14 -0500 received badge  Editor (source)
2016-06-13 09:25:46 -0500 asked a question RVIZ not visualizing all markers

I am trying to create two markers and add them to a MarkerArray and then publish it. However, only the last marker shows up. Any help with this is much appreciated!

pub = rospy.Publisher('site_markers', MarkerArray, queue_size=10)

markerArray = MarkerArray

marker1 = Marker()
marker1.header.stamp =
marker1.header.frame_id = "/vicon"
marker1.type = marker1.CYLINDER
marker1.action = marker1.ADD
marker1.pose.position.x = -9
marker1.pose.position.y = 0
marker1.pose.position.z = 0
marker1.scale.x = 1.0
marker1.scale.y = 1.0
marker1.scale.z = 0.01
marker1.color.r = 1.0
marker1.color.g = 0
marker1.color.b = 0
marker1.color.a = 0.7
marker1.lifetime = rospy.Duration.from_sec(0)
marker1.frame_locked = 0

marker2 = Marker()
marker2.header.stamp =
marker2.header.frame_id = "/vicon"
marker2.type = marker2.CYLINDER
marker2.action = marker2.ADD
marker2.pose.position.x = -5
marker2.pose.position.y = 4
marker2.pose.position.z = 0
marker2.scale.x = 1.0
marker2.scale.y = 1.0
marker2.scale.z = 0.01
marker2.color.r = 1.0
marker2.color.g = 0
marker2.color.b = 0
marker2.color.a = 0.7
marker2.lifetime = rospy.Duration.from_sec(0)
marker2.frame_locked = 0

while not rospy.is_shutdown():

Also when I do rostopic echo on the topic, it shows both markers being published, so that confused me as well.

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2016-06-09 12:17:54 -0500 asked a question Drawing Boundaries on Rviz for environment

My goal is to create a Rviz file that I can save and then use as a config file for future times when I run Rviz as explained in this link:

My aim is to publish lines on the grid that will serve as the environment boundaries for agents later on. From looking at the Rviz tutorials, I apparently have to publish through a ROS topic. So I guess my questions are:

  1. How will I execute the ROS topic from the file once I write the code?
  2. If I draw lines using the provided Points and Line List from Rviz, will the agents automatically not be able to pass through them, or do I have to edit them in a way so that they are block the agents' movements? Moreover, what if I want to draw lines that the agents can pass through?

Any help is much appreciated, thank you!

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2016-06-08 12:15:53 -0500 commented question Unable to Contact my Own Server

Now I'm getting this message when trying to roslaunch a package:

Invalid <arg> tag: environment variable 'ROS_HOSTNAME' is not set.

Arg xml is <arg default="$(env ROS_HOSTNAME)" name="machine"/>

2016-06-08 11:59:22 -0500 commented question Unable to Contact my Own Server

No, where do I set that up, and what do I set it to?

2016-06-08 10:59:06 -0500 asked a question Unable to Contact my Own Server

I am trying to run a roslaunch but I am unable to. Here is the error message:

Unable to contact my own server at [http://host-ubuntu:37730/].
This usually means that the network is not configured properly.

A common cause is that the machine cannot ping itself.  Please check
for errors by running:

    ping host-ubuntu

For more tips, please see

The traceback for the exception was written to the log file

I tried to do ping host-ubuntu, but it returns ping: unknown host host-ubuntu, or in other words I am not getting any ping.

I tried to follow the directions in Unable to contact my own server where the asker has a similar problem, but this did not help me as I could not even find those two lines of code in my .bashrc to edit. Any help on this would be much appreciated, thank you!

Here is my .bashrc file as well for more context:

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar

# make less more friendly for non-text input files, see lesspipe(1)
[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color) color_prompt=yes;;

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
    # We have color support; assume it's compliant with Ecma-48
    # (ISO/IEC-6429). (Lack of such support is extremely rare, and such
    # a case would tend to support setf rather than setaf.)

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a ...
2015-07-15 09:34:30 -0500 commented answer Creating a bag file out of a image sequence

So just to clarify, I know this code was written for the purpose of calibration, but can I take a series of images taken from a prior video stream, and patch them together again so the final .bag file is a video?

2015-07-15 09:34:30 -0500 commented answer Creating a bag file out of a image sequence

Are you using RGB images or mono?