All topics in root / namespace, difficult for multirobot environment

[ivan140]

Hi,

In the package fiducial_slam there are several subscribers and publishers which use the root (/) namespace. Here are the mentioned lines:

FiducialSlam::FiducialSlam(ros::NodeHandle &nh) : fiducialMap(nh) {
...
ft_sub = nh.subscribe("/fiducial_transforms", 1, &FiducialSlam::transformCallback, this);
--------------------------------------------------------------------------------------------
Map::Map(ros::NodeHandle &nh) : tfBuffer(ros::Duration(30.0)) {
...
robotPosePub =
    ros::Publisher(nh.advertise<geometry_msgs::PoseWithCovarianceStamped>("/fiducial_pose", 1));
cameraPosePub = ros::Publisher(
    nh.advertise<geometry_msgs::PoseWithCovarianceStamped>("/fiducial_slam/camera_pose", 1));

markerPub = ros::Publisher(nh.advertise<visualization_msgs::Marker>("/fiducials", 100));
mapPub = ros::Publisher(nh.advertise<fiducial_msgs::FiducialMapEntryArray>("/fiducial_map", 1));

When having several robots, each in its own namespace it makes it difficult to manage the fiducial_slam (remap...). I'd make a pull request with a fix, but want to ask you how you'd prefer it:

1. Pass two NodeHandles (pnh and nh) to these functions. This way, if a namespace is defined and you declare the subscriber with nh but without the / the nodehandle will use the namespace: /robot_1/fiducial_map
2. Pass only the private NodeHandle, as it is now, but create all publishers from the private namespace, which will result in: /robot_1/fiducial_slam/fiducial_map

What is the preferable way in your opinion?
Thank you in advance.
Ivan