  Zenith sky brightness maps in the V and B bands of the region of Catalonia
are presented in this paper. For creating them we have used the light pollution
numerical model Illumina v2. The maps have a sampling of 5x5 km for the whole
region with an improved resolution of 1x1 km for one of the provinces within
Catalonia, Tarragona. Before creating the final maps, the methodology was
tested successfully by comparing the computed values to measurements in
nineteen different locations spread out throughout the territory. The resulting
maps have been compared to the zenith sky brightness world atlas and also to
Sky Quality Meter (SQM) dynamic measurements. When comparing to measurements we
found small differences mainly due to mismatching in the location of the points
studied, and also due to differences in the natural sky brightness and
atmospheric content. In the comparison to the world atlas some differences were
expected as we are taking into account the blocking effect of topography and
obstacles, and also due to a more precise light sources characterization. The
results of this work confirm the conclusion found in other studies that the
minimum sampling for studying sky brightness fine details is of 1x1 km.
However, a sampling of 5x5 km is interesting when studying general trends,
mainly for vast areas, due to the reduction of the time required to create the
maps.
