Rezise of the map necessary?

asked 2014-10-08 04:55:19 -0500

Andromeda
875 ●38 ●50 ●65

updated 2014-10-08 07:58:25 -0500

Hi, I m trying to load a blank map with a defined dimension of [width, height] = [20, 20] but still it displays in Rviz just a small white square of constant dimension 6x6. I read this tutorial here and I put the right parameter in the costmap file:

global_costmap:
   global_frame: /map
   robot_base_frame: /base_link
   update_frequency: 3.0
   publish_frequency: 0.0  # For a static global map, there is generally no need to continually publish it
   static_map: true        # This parameter and the next are always set to opposite values. The global map is usually static so we set static_map to true
   rolling_window: false   # The global map is generally not updated as the robot moves to we set this parameter to false
   resolution: 0.01
   transform_tolerance: 1.0
   map_type: costmap
   width:  20
   height: 20

and

local_costmap:
   global_frame: /odom
   robot_base_frame: /base_link
   update_frequency: 3.0
   publish_frequency: 2.0
   static_map: false
   rolling_window: true
   width:  16
   height: 16
   resolution: 0.01
   transform_tolerance: 1.0

and here my map yaml file:

image: blank_map.pgm
resolution: 0.01
origin: [0, 0, 0]
occupied_thresh: 0.65
free_thresh: 0.196 # Taken from the Willow Garage map in the turtlebot_navigation package
negate: 0
width:  20
height: 20

Anyway I after many tries I foudn that the map is going to be resized every time I start the corresponding node:

[ INFO] [1412758776.217404554]: Using plugin "static_layer"
[ INFO] [1412758776.420654688]: Requesting the map...
[ INFO] [1412758776.643031834]: Resizing costmap to 600 X 600 at 0.010000 m/pix
[ INFO] [1412758776.741877357]: Received a 600 X 600 map at 0.010000 m/pix
[ INFO] [1412758776.769172167]: Using plugin "obstacle_layer"

and I m quite sure that causes the problem. Here and here I found similar problem but not the right solution.

How to solve this annoying problem?

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answered 2014-10-09 15:34:12 -0500

Andromeda
875 ●38 ●50 ●65

updated 2014-10-09 15:35:48 -0500

I must say that the answer given by David was very helpful and works. But I should admit that as a simple workaround I've created a bigger map using Gimp. Just create a brand new plane with the dimension you want, the above reported map dimension is the dimension in pixel of the image. So if you want to create a map 20x20 [meter], just create with Gimp a page 2000x2000, save it as .pgm file and you are done. The big vantage is that you don t need to play too much with your global and local_costmap files. The map is going to be visualized in RViz very nicely.

The second thing that I discovered is that the origin of your map must be integer, since double doesn't work. So if you have let's say:

image: my_map.pgm
resolution: 0.01
origin: [-10, -10, 0]
occupied_thresh: 0.65
free_thresh: 0.196 # Taken from the Willow Garage map in the turtlebot_navigation package
negate: 0
width:  20  # m   Don't forget to create a file with 2000 pixel width
height: 20  # m   Don't forget to create a file with 2000 pixel height

then put origin [-10,-10,0] as int and not as double or float.

I hope that it helps

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answered 2014-10-08 10:06:18 -0500

David Lu

10932 ●123 ●219 ●250 http://MetroRobots.com/

If you use a static costmap layer, the global costmap is automatically set to the size of that costmap.

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Hello David. Since ths static costmap layer is something new for me, do you mean that the following link could help me? Am I pointing to the right direction?