There is no definitive data set for Stonehenge measurements. There can never be because the various dimensions quoted come from surveyors who undertook their respective surveys in different epochs and the state of Stonehenge's construction varied greatly. Comparing, just as illustration, Petrie would have undertaken his at a time when the stones were in disarray - the lintels over uprights 29,30, 1 and 2 would have been leaning heavily outward - and current plans, however apparently accurate such as Anthony Johnson's (AJ) were prepared considerably later after a great deal of restoration.
So we can rely on AJ's plans as being perhaps the most precise available (at least publicly) in terms of post-restoration, and the high resolution offers opportunity for creating a benchmark. But, in turn, these rely on the restoration having been accurately undertaken, which however painstakingly expedited, is open to question. Equally Petrie's measurements, often used as "definitive" in many instances, actually can't be confidently accepted due to the condition of the layout at his time of survey, and he will have no doubt made assumptions and educated guesses.
As a result the door has been left open for various researchers to "adjust" dimensions to fit their own particular ideas and hypotheses. Unfortunately there is no way that any one researcher can actually be proven wrong, and the veracity of any hypothesis linked to "definitive" measurements, i.e. claimed to be the ones that were actually designed into the monument will depend on the quality of argument, supported by scientifically accepted evidence. Most hypotheses, both from academia and independent researchers fall far short of scientific rigour.
In this brief context, I have prepared a set of preliminary dimensions as in the images below. The purpose is to present dimensions, in one location, which have been scrutinised by both academia (hopefully) and independent researchers, from which existing theories can be rigorously reviewed or new hypotheses more confidently presented, whenever dimensions are involved. I've used various sources and put them together to produce a couple of high resolution plans - within practical means - from which the dimensions were determined.
At this stage I am just presenting the first set of dimensions to start the ball rolling, together with a diagram which is more or less self explanatory. I am preparing an accompanying set of notes detailing the methodology and explaining which can be taken with a finer tolerance as opposed to others which have to be treated with greater caution, or simply can't be trusted at all.
However, I will be looking initially to first reactions and comments as to which other dimensions should/might be included, to see if the plans I have will cover them, or how they might be best measured before adding to the list. It will be a work in progress over the coming months, with a view to creating that one stop answer to much of the confusion that appears to exist.
Please note that all measurements are in Imperial Feet. People will have to convert, to whichever hypothesis they are pursuing, themselves. It is not the purpose of this data set to support any particular theory - not even my own! All dimensions are rounded to four decimal places maximum.
Click to enlarge
Thanks to Richard for sharing this ongoing work with us