A web service to allow interactive browsing of data from the DESI Imaging Legacy Surveys (and other surveys) data releases.

Uses the LeafletJS library on the client side, the Django Python web framework on the server side, and a whack of code in between.

Running at https://www.legacysurvey.org/viewer

Dependencies include:

• astrometry.net
• tractor
• legacypipe
• astropy
• Django

You will need to create a viewer/settings.py file for your site. There is a viewer/settings_common.py file with defaults, and settings files for a number of sites, as a guide.

Each available layer (image layer) and overlay (catalog or markers) requires some data (not included in this repository). Many layers follow the pattern of having:

• data/LAYER contains (symlinks to) the raw imaging data
• data/tiles/LAYER contains pre-rendered JPEG tiles
• data/scaled/LAYER contains scaled-down images

The overlays are less regular in their data layouts, but:

• Gaia-DR2: we expect data/gaia-dr2/ to contain healpixed tiles named chunk-#####.fits