Hi,

I'm using ROS Indigo on Ubuntu 14.04

I am in the process of writing an autonomous drive algorithm for my Turtlebot, and I've written a function that is meant to search the local costmap for a safe goal to send to the actionclient for move_base.

So, in my function, I call a function that picks up the most recent OccupancyGrid published to move_base/local_costmap/costmap. I then copy the callback to a global variable called "localgrid", which my function examines for obstacles.

void localmapcallback(const nav_msgs::OccupancyGrid::ConstPtr& msg)
{        
    localgrid.info = msg->info;     
    localgrid.header = msg->header;
    localgrid.data = msg->data;

    gotmap = true;
    ROS_INFO("Got a local map! Origin is %f,%f", msg->info.origin.position.x,msg->info.origin.position.y);
}

//  ^ localmapcallback

What I've noticed, however, is that, no matter where I am in the global map, the origin on the occupancy grid never changes!

Movebase is being launched from the default AMCL demo launch, so I can see that the local costmap is configured properly, i.e., `rollingwindowis settrue`. The local costmap also looks fine in RViz.

Also, in my program, I have my own self-updating global Costmap 2DROS named localmap_

localmap_ = new costmap_2d::Costmap2DROS(std::string("newlocal_costmap"), tf_); 

So what I have done, is add a lot of debug statements in my "safe goal" function. I compare the difference between the origin of the OccupancyGrid ("localgrid") and the Costmap2DROS ("localmap_") after running the above callback:

ROS_INFO("Looking for a safe goal. The local OG origin is %f,%f",localgrid.info.origin.position.x,localgrid.info.origin.position.y);

costmap_2d::Costmap2D* mymap = localmap_->getCostmap();
boost::unique_lock< boost::recursive_mutex> lock(*(localmap_->getCostmap()->getMutex()));

ROS_INFO("Looking for a safe goal. The local costmap origin is %f,%f",mymap->getOriginX(),mymap->getOriginY());
boost::unique_lock< boost::recursive_mutex> unlock(*(mymap->getMutex()));

And this is what I get when I run the code while the robot is far from its starting point:

(Apologies for the photo instead of pasted text -- I can't figure out how to copy output from GDB. Also, apologies for my coding conventions. They're sloppy and I need to fix them eventually)

So, why doesn't the OccupancyGrid have a meaningful origin like the local Costmap2DROS does?

My code is quite long, so that is why I've refrained from posting everything here, but please do let me know if I need to put anything else here.

Thanks!