In my understanding so far, I understand that:

• odom -> base_footprint is determined by the odometry data (Eg: by gazebo)

• map -> base_footprintis the one
  estimated by: amcl

Based on the above two, even though amcl calculates map -> base_footprint, it actually publishes map -> odom.

I wanted to understand how does amcl initially estimate the 'map -> basefootprint' just after getting started ? Do the parameters `initialposex,initialposeyandinitialpose_a` play a role in this ?