-----Original Message-----
From: powys-bounces(a)rootsweb.com [mailto:powys-bounces@rootsweb.com]
On Behalf Of Alison Bryan
Sent: 04 November 2013 18:56
To: powys(a)rootsweb.com
Subject: Re: [POWYS]
www.cymru1900wales. org - Response to questions
<<The mapping used on the site is the 2nd edition Ordnance Survey County
Series at a scale of 6"/mile (1:10,560). In Wales this was surveyed between
1899 and 1909 (please see image attached), but as you have spotted, some
maps were published slightly later, with additional relevant transcriptions
added. Interestingly, the data we have shows that Rhayader was surveyed
around 1903, so it is surprising that the find spot indicated in 1910 is
present on the map - I will investigate further>>
It was quite common for there to be considerable delays between an initial
main survey and the actual publication of an Ordnance Survey map. Contrary
to popular belief, the date shown in a footnote should not be taken as a
particularly reliable indicator. Different aspects would be revised at
different times and the map would seldom (or probably never) be an precise
record of the exact situation at any one particular moment. An Ordnance map
is a complex document and important new features were often selectively
added long after the initial survey. An example that I often quote from
nearer to my own area is the 1st six-inch Lancashire edition of "1851",
which quite clearly shows the Coniston Railway line - not built until 1859.
Hence one needs to settle for merely interpreting the approximate dates,
with the aid of other sources - chiefly meaning local knowledge. In many
cases it will now be impossible to pinpoint the exact date when a particular
feature was revised by the mapmakers - not even with the use of the Ordnance
Survey's own archives.
Despite the use of modern aerial photography, the same may hold true even
today. If for example a public footpath disappears into a wood, its course
might well become invisible from the air and it therefore cannot be traced
without physically sending someone down on the ground to walk along it and
check. Or it may simply be assumed (perhaps erroneously) that the course has
been unchanged since the previous survey. Similarly one might sometimes
presume that the names, block outlines and usages of particular buildings
have also been unaltered. When taking many hundreds of properties into
account, this might not necessarily be the case. Or the information (usually
gathered by enquiry from local people) might not always have been accurate
in the first place.
AJ