SDSS DR7 survey mask polygon file

<p>This is a polygon file for the <a href="https://github.com/mollyswanson/mangle">Mangle</a> software that defines the survey mask geometry for the <a href="https://classic.sdss.org/dr7/">SDSS DR7</a>. It was originally available at this, now defunt, <a href="http://space.mit.edu/~molly/mangle/download/data/sdss_dr72safe0_res6d.pol.gz">link</a>. The file was originally created and distributed by <a href="https://github.com/mollyswanson">Molly Swanson</a>.</p>