ROS octomap output

[Tiago]

Hello,

In the ROS output from command "roslaunch ocotmap_server octomap_mapping.launch", what is the most significant difference between /occupied_cells_vis_array and /octomap_point_cloud_centers? I know that the first is the type octomap and the second the type PointCloud2, but I want to know the difference between the info that each one provides.

Best Regards,
Tiago

[Armin Hornung]

Hi Tiago,

please check the octomap_server documentation, it explains all the
topics and types:
http://wiki.ros.org/octomap_server


I would suggest to use neither of the topics and directly use
octomap_binary or octomap_full instead, which is much more efficient.
The octomap RViz plugin (http://wiki.ros.org/octomap_rviz_plugins)
allows you to directly visualize the OctoMap msg.

Best regards,
Armin

[Tiago]

Hi,

Thanks. I saw the link that told me and notice the difference between the topics. Thanks.

Best Regards,
TIago

[Tiago]

Hello,

I found other doubt in the messages octomap_binary and octomap_full.
Both messages are of type octomap_msgs/Octomap, so in the octomap_full where is write the probabilities if both uses the same data struct (http://docs.ros.org/api/octomap_msgs/html/msg/Octomap.html) .

Sorry for re-open the topic.

Best Regards,
Tiago

[Armin Hornung]

Am 06.08.2015 um 15:42 schrieb Tiago:
> Hello,
>
> I found other doubt in the messages octomap_binary and octomap_full.
> Both messages are of type octomap_msgs/Octomap, so in the octomap_full
> where is write the probabilities if both uses the same data struct
> (http://docs.ros.org/api/octomap_msgs/html/msg/Octomap.html) .

Yes, the same data struct is used for both messages. It's basically just
header information and a binary stream 'data', in which all kinds of
octrees could be stored. The flag 'binary' denotes what is stored inside
(binary or full occupancy).

Simply use the conversion functions from conversions.h
(http://docs.ros.org/jade/api/octomap_msgs/html/conversions_8h.html) to
correctly write either full probabilities or binary information. In both
cases the binary data stream of the Octomap msg will be used.

Cheers,
Armin

[Tiago]

Hello,

Thanks. I will try like you said. Any doubts I post here. Thanks.

Best Regards,
Tiago

[Tiago]

Hello,

Sorry for re-open the topic, but I have some doubts.
If I subscribe to the topic /octomap_binary or /octomap_full how I can obtain the parameter "const OctomapT& octomap" that is necessary to use the functions binaryMapToMsgData() or fullMapToMsgData()?
Sorry for make a basic question, but I have tried and I cannot found some way to obtain this parameter.

Best Regards,
Tiago

[Christian Dornhege]

Hi,

these functions are for the other way around. They take an octomap and
produce message data for publishing. If you are subscribing you need to
create an octomap from the message data.

Best,
Christian

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[Tiago]

Hi,

Thanks. Now I could understand.

Best Regards,
Tiago

[Tiago]

Hello,

Sorry for re-open the topic, but I try to read the data (getProbHit) from /octomap_binary and the value is always 0.7, even when I have and haven't obstacles in front of my sensors. For this value I create the octomap (using octomap::octree) from /octomap_binary using the binaryMsgToMap functionand retreat whit the value getProHit. What can I do ing wrong?

For the message /octomap_full I try to do something similar and I can't get the probabilities. Any suggestions?

Best Regards,
Tiago