Theatre of the Empire of Great Britain
The Theatre was first published in 1611, and this is the 1676 reprint.
All that has changed is the addition of Arthur Capel's Arms in the bottom left corner (& 1662 as its date, from an earlier edition by the same publishers). The maps in the atlases have text on the back; maps were also sold individually with no text on the back.
Displayed scale of 6 miles = 56mm, or 2.7 miles/inch; actual scale = 3.6 miles/inch, or 1:230,000.
The Essex map was described by Speed as being based on Saxton, plus the description of John Norden; he didn't use Norden's map as the Saxton errors are still present.
The Speeds are one of the most widely collected (& available) antique maps - printed as it was in large numbers.