global_map.cpp

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/*
 * Copyright (c) 2008, Willow Garage, Inc.
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#include <graph_slam/global_map.h>
#include <pose_graph/transforms.h>
#include <occupancy_grid_utils/ray_tracer.h>
#include <boost/foreach.hpp>
#include <boost/optional.hpp>

namespace graph_slam
{

namespace pg=pose_graph;
namespace nm=nav_msgs;
namespace gu=occupancy_grid_utils;

using std::min;
using std::max;

nm::MapMetaData getGridBounds (const pg::NodePoseMap& poses, const double resolution)
{
  boost::optional<double> min_x, min_y, max_x, max_y;
  BOOST_FOREACH (const pg::NodePoseMap::value_type& e, poses) {
    const double x = e.second.position.x;
    const double y = e.second.position.y;
    if (!min_x) {
      min_x = x;
      max_x = x;
      min_y = y;
      max_y = y;
    }
    else {
      min_x = min(x, *min_x);
      min_y = min(y, *min_y);
      max_x = max(x, *max_x);
      max_y = max(y, *max_y);
    }
  }

  nm::MapMetaData info;
  info.origin.orientation.w = 1.0; // Identity quaternion
  info.origin.position.x = *min_x-PADDING;
  info.origin.position.y = *min_y-PADDING;
  info.width = (*max_x-*min_x+2*PADDING)/resolution;
  info.height = (*max_y-*min_y+2*PADDING)/resolution;
  info.resolution = resolution;
  
  return info;
}


nm::OccupancyGrid::Ptr generateGlobalMap (const pg::PoseGraph& graph, const pg::NodePoseMap& poses,
                                          const double resolution)
{
  nm::MapMetaData bounds = getGridBounds(poses, resolution);
  ROS_DEBUG_STREAM_NAMED("global_map", "Generating global map with dimensions " << bounds);
  gu::OverlayClouds overlay = gu::createCloudOverlay(bounds, pg::OPTIMIZED_FRAME,
                                                     gu::DEFAULT_OCCUPANCY_THRESHOLD, 30.0);
  BOOST_FOREACH (const pg::NodePoseMap::value_type& e, poses) {
    if (graph.hasCloud(e.first)) {

      // Transform the cloud to the optimized frame
      gu::LocalizedCloud::ConstPtr base_frame_cloud = graph.getCloud(e.first);
      const Eigen3::Affine3d base_to_opt = pg::poseToWorldTransform(e.second);
      gu::LocalizedCloud::Ptr opt_frame_cloud(new gu::LocalizedCloud());
      opt_frame_cloud->sensor_pose.pose = pg::applyTransform(base_to_opt, base_frame_cloud->sensor_pose.pose);
      opt_frame_cloud->sensor_pose.header.frame_id = pg::OPTIMIZED_FRAME;
      opt_frame_cloud->cloud.points = base_frame_cloud->cloud.points;

      // Overlay it onto the grid
      gu::addCloud(&overlay, opt_frame_cloud);
    }
  }

  nm::OccupancyGrid::Ptr grid = gu::getGrid(overlay);
  grid->header.stamp = ros::Time::now();
  ROS_DEBUG_NAMED ("global_map", "Done generating global map");
  return grid;
}


} // namespace graph_slam