call traversability_footprint service always failed

[lukechencqu]

hi:
we used the traversability_estimation rospack for mapping the robot footprint cost map for our quadruped robot's body-path planner.
the issue is that: when we call traversability_footprint service, this service always gived the error like"service call failed: service [/traversability_estimation/traversability_footprint] respond with an error: GridMap::at(...): No map layer 'traversability_slope' available", other similar errors are maybe traversability_step or traversability_roughness layer not available.
so, we did not know what caused this service call failure, could you give us some advice? thank you!