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2017-06-06 00:52:09 -0600 commented answer Node not able to get its namespace parameters

That would have helped me debug the problem, but I really want it the way I wrote it, it's just the error that is confus

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2017-06-05 13:28:57 -0600 marked best answer Node not able to get its namespace parameters

My code looks like:

rospy.init_node('images_feeder', anonymous=True)
params = rospy.get_param('~')

I'm pretty sure it used to work "before", but now it gives:

KeyError: '~'

The parameters server seems to be running because I can for example successfully:

print rospy.get_param('/rosdistro')

(which is indigo by the way). Between "before" and now, I performed several ros (system) packages updates, and maybe changed the way I run things (currently "roscore" in one terminal, "rosrun x y" in another).

Could this be a regression, or is there something more to do, so that the node can "get its namespace" ? Thanks.

2017-06-05 13:28:52 -0600 commented answer Node not able to get its namespace parameters

So the confusing thing is: if the node does not have any parameter, it will fail on get_param('~'). I guess it's an impl

2017-06-05 13:28:43 -0600 commented answer Node not able to get its namespace parameters

Actually, despite the wording of the question, I am not trying to get the namespace, but to later do: x = params['x'] y

2017-06-05 13:28:35 -0600 commented answer Node not able to get its namespace parameters

So the confusing thing is: if the node does not have any parameter, it will fail on get_param('~'). I guess it's an impl

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2017-06-05 13:27:40 -0600 commented answer Node not able to get its namespace parameters

Actually, despite the wording of the question, I am not trying to get the namespace, but to later do: x = params['x'] y

2017-06-05 09:13:02 -0600 asked a question Node not able to get its namespace parameters

Node not able to get its namespace parameters My code looks like: rospy.init_node('images_feeder', anonymous=True) para

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2016-11-10 14:54:51 -0600 commented answer Viewing images inside messages

Thanks for formatting my answer :)

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2016-11-10 01:44:32 -0600 commented question Viewing images inside messages

Actually it works with simply topic_tools transform:

$ rosmsg show stereo_camera/RectifiedPair
std_msgs/Header header
  uint32 seq
  time stamp
  string frame_id
sensor_msgs/Image left
...

$ rosrun topic_tools transform /rectified_pair /rect_left sensor_msgs/Image

I'm not sure relay_field is necessary anymore. At least in my case, transform can relay simply enough.

2016-11-10 01:21:13 -0600 commented answer catkin_make failure due to Python Anaconda

Shouldn't this read: delete your build folder after turning on anaconda ? Can't cmake find the anaconda python and cache it, this way ?

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2016-11-05 13:55:58 -0600 commented question Viewing images inside messages

I managed to use echo, but am struggling with relay_field. (I saw your question about it on github, thanks for digging !). I think it's not very practical, from the looks of it: you'd have to explicit every single field of the Image you want to produce, it seems (and even that I didn't manage).

2016-11-05 13:53:51 -0600 commented question Viewing images inside messages

The synchro middleware looks cool, especially to sync separated sources, but in my case I think it would be adding unneeded complexity. Plus I'd like to annotate the images with custom fields, so that would make a lot of things to synchronize, just for the sake of having pure Image messages.

2016-11-05 08:10:15 -0600 commented question Viewing images inside messages

Synchronizing messages based on a timestamp would be much harder than just receiving pairs that I know by design have been generated together. The images are correlated at the source, I see as wasteful separating them, then doing additional efforts to re-correlate them.

2016-11-05 02:52:25 -0600 asked a question Viewing images inside messages

I am writing a system with a stereo camera, and would like to group left/right image pairs together as soon as possible, to reduce desynchronization due to asynchronous exchanges. It results that my messages are not Image themselves, but containing 2 Image. Is there a way to easily see images inside any kind of message ? Ideally something like rqt_image_view, but able to peek inside topic messages fields, rather than just show those that are of top-level type Image ?

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2016-09-24 07:04:09 -0600 commented answer Confusion system/rosdep/rosmake/catkin

(it's like it is starting a new core or something, hiding the output in log files, ... whereas I just want to launch one node).

2016-09-24 07:03:59 -0600 commented answer Confusion system/rosdep/rosmake/catkin

... but it is unclear to me whether I should use param:=value or _param:=value. Also parameters seem to be remembered somewhere across runs, which is not what I want. I also tried using .launch files, but it seems to require "roslaunch" instead of "rosrun", which seems too much

2016-09-24 07:03:55 -0600 commented answer Confusion system/rosdep/rosmake/catkin

Thanks, that clarifies a bit. Now I'm confused about launching a node with parameters. I apt-installed some package containing a binary, and can run the binary with "rosrun pack_name bin_name", but I need to give it particular parameters. I tried adding them to the rosrun command line ...

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2016-09-24 04:58:39 -0600 asked a question Confusion system/rosdep/rosmake/catkin

I'm trying to use a package for which I suspect instructions are outdated, so I need a solid understanding of the process. However, even after following some ROS tutorials, I'm still confused. I'm on Linux (Mint), so in my view, there are 2 things:

  • files installed via apt, system-wide (can go wherever: /etc, /opt, and more ...) and requiring sudo.
  • files contained inside the folder designed as "catkin worspace", owned by my personal user

I have a hard time understanding:

  • whether when I "sudo apt-get install ros-something", that something is immediately runnable, or needs additional building
  • what "rosdep install" is supposed to do: it does not seem to require root, so where does it write things ?
  • what "rosmake" is supposed to do: idem, does not seem to require root, but does not seem to interact with the catkin workspace either

Any clarifications would be greatly appreciated !