reading a specific tf frame

edit

Hello,

Does anyone know if there is a function that lets you read a specific tf frame such as:

.readFrame("/base_link" , time(latest info published), //frame reference);

I need to be able to read a specific frame. I know you can do: tf::StampedTransform transform; .lookUpTransform("target frame", "original frame" , time , transform);

The reason why I don't want a lookUpTransform is because I am actually not trying to take the transform of anything here. Unless I am not understanding something here, I would appreciate some feed back here.

This is what I have so far. Please give me some feed back on the frames that I am using. Because to my understanding The "base_link" frame should be transformed to the "map" frame, If I have a .yaml map file running on top of the navigation stack right?

  #include <ros/ros.h>
#include <geometry_msgs/Twist.h>
#include <geometry_msgs/TransformStamped.h>
#include <tf/transform_listener.h>
#include <tf/transform_broadcaster.h>
#include <tf/transform_broadcaster.h>

using namespace std;

int main(int argc, char** argv) {
    ros::init(argc, argv, "readTFframe");
    ros::NodeHandle nh;
        tf::Transform leader_base_link;
    tf::Quaternion q;
    tf::Vector3 v;  
    tf::TransformListener listener;
    geometry_msgs::TransformStamped transformConverter;

    ros::Time current_time, last_time;
        current_time = ros::Time::now();
        last_time = ros::Time::now();

    ros::Publisher pub = nh.advertise<geometry_msgs::TransformStamped>("/leader/tf", 1);

    static tf::TransformBroadcaster br;

    double yaw; 


ros::Rate loopRate(10);
while(ros::ok()){
    tf::StampedTransform transform;
    current_time = ros::Time::now();


    try {
                        listener.waitForTransform("base_link", "base_footprint", ros::Time(0), ros::Duration(10.0));
            listener.lookupTransform("base_link", "base_footprint", ros::Time(0), transform);
        }
        catch (tf::TransformException &ex) {
            ROS_ERROR("%s",ex.what());
        }
    yaw =   tf::getYaw(transform.getRotation()); 
        v.setValue(transform.getOrigin().x() , transform.getOrigin().y() , transform.getOrigin().z());

    leader_base_link.setOrigin(v);
    q.setRPY(0.0, 0.0, yaw);
    leader_base_link.setRotation(q );
    br.sendTransform(tf::StampedTransform(leader_base_link, ros::Time::now(), "base_footprint", "leader_base_link"));

/*
    ROS_INFO_STREAM("X pose " <<  transform.getOrigin().x() );
    ROS_INFO_STREAM("Y pose " << transform.getOrigin().y() );
    ROS_INFO_STREAM("Z pose " << transform.getOrigin().z() );
    ROS_INFO_STREAM("Yaw "<< yaw );
*/  
double th = yaw;
 geometry_msgs::Quaternion odom_quat = tf::createQuaternionMsgFromYaw(th);
    transformConverter.header.stamp = current_time; 
    transformConverter.header.frame_id = "base_footprint";
    transformConverter.child_frame_id = "base_link";
    transformConverter.transform.translation.x = transform.getOrigin().x();
    transformConverter.transform.translation.y = transform.getOrigin().y();
    transformConverter.transform.translation.z = transform.getOrigin().z();
    transformConverter.transform.rotation = odom_quat;
    ROS_INFO_STREAM("X pose " <<  transformConverter.transform.translation.x );
    ROS_INFO_STREAM("Y pose " << transformConverter.transform.translation.y);
    ROS_INFO_STREAM("Z pose " << transformConverter.transform.translation.z );
    ROS_INFO_STREAM("Yaw "<< yaw );

    loopRate.sleep();
}

    return 0;
}

This is my current code when I run it I can see that the values are being passed to the transformConverter transform that is converting the desired transform from tf::StampedTransform to geometry_msgs::TransformStamped . This way it can be published on the topic /leader/tf. The only thing is I can see the values are passed through ROS_INFO. But they are not being published now on the topic.