Legacy Survey DR4 ========================================= This product contains the tractor catalogues from the [Legacy Survey DR4](http://legacysurvey.org/dr4/description/). The downloading and processing of this data is described in the Jupyter Notebook. The Legacy Survey officially includes the DECaLS DR3 data however, we process that separately since it has different coverage on a different instrument. This data product therefore contains data from only the Beijing-Arizona Sky Survey (BASS) and the Mayall z-band Legacy Survey (MzLS).