about resolution on yaml

edit

My question:
As hokuyo laser URG-04LX has 1mm resolution, I should set 0.001 as resolution on global_costmap_params.yaml?
Because the resolution of hokuyo laser URG-04LX is 1mm. or Should I edit this parameter to match unit [m/pixel] in case that pgm has 312X512 pixels and actual map size has 2.7m wide and 5.3m height?
Could anybody tell me your experience?

Next article says more detailed information. I have a laser3.yaml and laser3.pgm like this. laser3.png
laser3.yaml

image: /home/turtlebot/laser3.pgm
resolution: 0.050000
origin: [-1.000000, -12.200000, 0.000000]
negate: 0
occupied_thresh: 0.65
free_thresh: 0.196

So, I'm editing my code like this.

map_upperboud = costmap_->getSizeInMetersX() -costmap_->getOriginX();
map_lowerbound = costmap_->getOriginX();
ROS_WARN("Setting upper bound and lower bound of map x-coordinate to (%f, %f).", map_upperbound, map_lowerbound);

When I execute this program, I get a next message.
[ WARN] [1404074825.515283246]: Setting upper bound and lower bound of map x-coordinate to (16.975000, -1.000000).
[ WARN] [1404074825.515418641]: Setting upper bound and lower bound of map y-coordinate to (37.775000, -12.200000). I think getOriginX() reads laser3.yaml. Actually, The map have 2.7m in X-axis and 5.3m in Y-axis. But, The result has 16.95 in X-axis and 37.775 in Y-axis. laser3.png that actually is laser3.pgm has 320X512 pixels. If calculating pixels, origin data and resolution in yaml with getSizeInMetersX(), I get 16.975 and 37.775.
So, resolution of parameter is written on laser3.yaml after reading a resolution in global_costmap_params.yaml.