read data from octomap_full/octomap_binary

edit

You can use octomap_msgs/conversions.h just include this file and then you can use all the fuctions for example:

octomap_msgs::binaryMsgToMap(), to get the map from the octomap_binary, then you can iterate on the leafs of the tree as follows:

for (octomap::OcTree::leaf_iterator it = map->begin_leafs(); it != map->end_leafs(); ++it) 

{
  std::cout<< "Node center: " << it.getCoordinate();

  std::cout<< " value: " << it->getValue()<< "\n";
}

check this slide could be helpfull