Schematic diagram of the radiative transfer of hydrogen RRLs and continuum emission in the new model. The large blue circle shows the boundary of the spherical H II region. The blue asterisks represent the grid points for which the mean incident radiation field needs to be calculated. The dashed black lines show the radiation transfer paths in different directions. The arrows indicate the direction of propagation of the RRLs and the continuum emission. R and Z are the normalized radial and axial coordinates in the axisymmetric coordinate system.