Why is going to space crucial to map dark matter?

A key promise of the Euclid mission is to explore the evolution of the dark Universe. The foundation of this ambitious program is a large optical and near-infrared imaging survey. Euclid’s cosmic map will depict more than one billion galaxies out to 10 billion light-years, making it the biggest and most detailed cosmological data set of our age. How does the quality of the first Euclid images compare to another reference cosmological data set, the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Survey?