topic /scan of hokuyo node can't link to the /base_scan of gmapping node

edit

If you don't care about anything but the laser's position in the map, you can skip the extra transform and just specify the frame_id param when launching the hokuyo_node:

• rosrun hokuyo_node hokuyo_node scan:=base_scan _frame_id=base_link

or

• <node pkg="hokuyo_node" type="hokuyo_node" name="hokuyo" >

  <param name="frame_id" value="base_link" />

  <remap from="scan" to="base_scan" />

  </node>

I believe you can also specify the frame that gmapping uses, in the same fashion.

I think you you can also use urg_node to replace hokuyo_node