how to get real-time access to grid data from map generated by gmapping?

edit

Thanks for your reply. I've checked that out, but the map data there is a 1 dimention data and I could not figure out how to convert it to the actual 2 dimention array. Do you know how to do this?

Hi!, did you look at the content of the OccupancyGrid Message?, following the documentation this message, " represents a 2-D grid map, in which each cell represents the probability of occupancy.". So i think it should be a 2D info. Are you sure you are looking at the correct topic?

hi,i am having the same issue,occupancy grid does say its 2D but int8[] data is one dimensional which only gives information if the cell if empty or not but i cant seem to find the (x,y) coordinates related to each of the cell.Do i have to do it myself by using loops or some other library maybe?

@az As for my case, I implemented my own conversion and it's a easy one: def convertTo2DArray(): for i in range(map_width): for j in range(map_heigh) slam_map[i][j] = raw_map[i + j * map_width]

where the width and height are obtain from map message received from 'map' topic.

Thanks alot!

Essentially, the grid data is in row-major index format - which means if the width of the row (which you can get from map.info.width) is 1000,

map.data[0] = [0,0]

map.data[356] = [356,0]

map.data[1000]= [0,1]

map.data[72653]=[653,72]

map.data[ i ]=[(i%width),(int)(i/width)]