I'm trying to do the gmapping in gazebo tutorial found here but I am getting an error with both my local and global costmaps.

The three launch files that I use are turtlebotgazebo/world.launch, turtlebotgazebo/gmapping.launch, and turtlebotrvizlaunchers/view_navigation.launch. When RVIZ shows up, I have an error in both the local and global costmaps which says "No map received" and "No transform from [] to [map]"

Does anyone know what I should do or where I should start to look?