  The determination of reliable distances to Planetary Nebulae (PNe) is one of
the major limitations in the study of this class of objects in the Galaxy. The
availability of new photometric surveys such as IPHAS covering large portions
of the sky gives us the opportunity to apply the "extinction method" to
determine distances of a large number of objects. The technique is applied to a
sample of 137 PNe located between -5 and 5 degrees in Galactic latitude, and
between 29.52 and 215.49 degrees in longitude. The characteristics of the
distance-extinction method and the main sources of errors are carefully
discussed. The data on the extinction of the PNe available in the literature,
complemented by new observations, allow us to determine extinction distances
for 70 PNe. A comparison with statistical distance scales from different
authors is presented.
