Kinetic, Linux 16.04
I've done an experiment with a SLAM algorithm (gmapping) which makes a 'map' in rviz, from black and white cells (this is the occupancy grid). I then use a little script to save that map to a pgm.
The map looks like this: .
As you can see, a nice little map. The algorithm figured out its data and printed it as a reasonably straight, accurate map.
So I use this script from the 'occupancy_grid_server' package (I got from I know not where) to save the map:
#include
#include "ros/ros.h"
#include "ros/console.h"
#include "nav_msgs/OccupancyGrid.h"
#include "tf2/LinearMath/Matrix3x3.h"
#include "geometry_msgs/Quaternion.h"
using namespace std;
/**
* @brief Map generation node.
*/
class MapGenerator
{
public:
MapGenerator(const std::string& mapname) : mapname_(mapname), saved_map_(false)
{
ros::NodeHandle n;
ROS_INFO("Waiting for the map");
map_sub_ = n.subscribe("/map", 10000, &MapGenerator::mapCallback, this); }
void mapCallback(const nav_msgs::OccupancyGridConstPtr& map)
{
ROS_INFO("Received a %d X %d map @ %.3f m/pix",
map->info.width,
map->info.height,
map->info.resolution);
std::string mapdatafile = mapname_ + ".pgm";
ROS_INFO("Writing map occupancy data to %s", mapdatafile.c_str());
FILE* out = fopen(mapdatafile.c_str(), "w");
if (!out)
{ ROS_ERROR("Couldn't save map file to %s", mapdatafile.c_str());
return; }
fprintf(out, "P5\n# CREATOR: Map_generator.cpp %.3f m/pix\n%d %d\n255\n",
map->info.resolution, map->info.width, map->info.height);
for(unsigned int y = 0; y < map->info.height; y++) {
for(unsigned int x = 0; x < map->info.width; x++) {
unsigned int i = x + (map->info.height - y - 1) * map->info.width;
if (map->data[i] == -1) { //occ [0,0.1)
fputc(127, out);
} else if (map->data[i] <= +100) { //occ (0.65,1]
float value = 254-(map->data[i]*2.54);
fputc(value, out);
} else { //occ [0.1,0.65]
fputc(127, out);
}
}
}
fclose(out);
std::string mapmetadatafile = mapname_ + ".yaml";
ROS_INFO("Writing map occupancy data to %s", mapmetadatafile.c_str());
FILE* yaml = fopen(mapmetadatafile.c_str(), "w");
geometry_msgs::Quaternion orientation = map->info.origin.orientation;
tf2::Matrix3x3 mat(tf2::Quaternion(
orientation.x,
orientation.y,
orientation.z,
orientation.w
));
double yaw, pitch, roll;
mat.getEulerYPR(yaw, pitch, roll);
fprintf(yaml, "image: %s\nresolution: %f\norigin: [%f, %f, %f]\nnegate: 0\noccupied_thresh: 0.65\nfree_thresh: 0.196\n\n",
mapdatafile.c_str(), map->info.resolution, map->info.origin.position.x, map->info.origin.position.y, yaw);
fclose(yaml);
ROS_INFO("Done\n");
saved_map_ = true;
}
std::string mapname_;
ros::Subscriber map_sub_;
bool saved_map_;
};
#define USAGE "Usage: \n" \
" map_saver -h\n"\
" map_saver [-f ] [ROS remapping args]"
int main(int argc, char** argv)
{
ros::init(argc, argv, "map_saver");
time_t thetime = time(0);
std::string dt = ctime(&thetime);
std::string mapname = dt+"map";
for(int i=1; i
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