  Synoptic maps of solar EUV intensities have been constructed for many decades
in order to display the distribution of the different EUV emissions across the
solar surface, with each map representing one Carrington rotation (i.e., one
rotation of the Sun). This paper presents a new solar EUV synoptic map dataset
based on full-disk images from Solar and Heliospheric Observatory/Extreme
Ultraviolet Imaging Telescope (SOHO/EIT) and Solar Dynamics
Observatory/Atmospheric Imaging Assembly (SDO/AIA). In order to remove the
significant and complicated drift of EIT and AIA EUV intensities due to sensor
degradation, we construct the synoptic maps in standardized intensity scale. We
describe a method of homogenizing the SOHO/EIT maps with SDO/AIA maps by
transforming the EIT intensity histograms to AIA level. The new maps cover the
years from 1996 to 2018 with 307 SOHO/EIT and 116 SDO/AIA synoptic maps,
respectively. These maps provide a systematic and homogenous view of the entire
solar surface in four EUV wavelengths, and are well suited, e.g., for studying
long-term coronal hole evolution.
