  Imaging polarimetry is a useful tool to reveal the 3D structure of dust
distributions and to localize embedded young stellar objects. We present maps
of the linear polarization at 2.2 micron for three ultra-compact HII regions
(G192.16-3.82, G331.28-0.19, G339.88-1.26) and the methanol maser source
G305.21+0.21. From the polarization maps, we draw conclusions on the morphology
of these objects and the presence of luminous illuminating sources.
