For many wildlife recording purposes, not just lepidoptera, the Watsonian (botanical) Vice-County number is often required. Most of present-day Gloucestershire is in one of two vice-counties: VC33 (East Gloucestershire) and VC34 (West Gloucestershire). As a result of various administrative boundary changes since the VC boundary system was defined, there are several areas of VC33 or VC34 outside the present-day counties of Gloucestershire and South Gloucestershire, and there are also several areas of other adjacent vice-counties within Glos. or South Glos.
Some years ago for my own recording purposes I obtained digitised VC boundary data from the National Biodiversity Network (NBN), and for use whilst out recording I converted the VC33 & VC34 boundaries to GPS tracks which are displayed on the map page of my Garmin Etrex Vista HCx GPS. Under the Ordnance Survey Open Data Licence, these files can now be made available for others to download from this web page.
The number of VC33 & 34 boundary points in the NBN data was too large for the track storage capacity of my GPS, so the points were sampled in a way which ensured that all the omitted points were within 4 metres of the resulting tracks. This brought the total number of points below 8,000, enabling the boundaries to be converted to a total of 16 track files each with at most 500 points, the maximum for a single track stored for display purposes.
The resulting boundary grid reference points were converted to latitude & longitude values for GPS track purposes using the algorithms published on the Ordnance Survey website (including datum conversion). I used a relatively simple algorithm suitable for applications with an accuracy of 5 metres or more.
The resulting sets of latitude & longitude pairs were formatted as simulated .gpx track files, based on the format of a track file recorded by the GPS. The 16 track files were loaded into the GPS using its interface software, and display options were selected so that the VC boundaries appear prominently on the map page display. In spite of the potential lack of precise accuracy (an error of up to 4m + 5m + the accuracy of the GPS measurement at the time) the actual boundary is usually easy to determine using the GPS whilst out recording in places where it follows field boundaries, streams, roadsides etc. The GPS display is particularly useful near Sapperton and in Hailey Wood where the VC33/34 boundary follows the underground route of the disused canal tunnel!
To download each file, right click on its link below and select Save Target As. The 10 files with names starting VC33 collectively contain the complete boundary for VC33, and the 6 files with names starting VC34-33 contain the VC34 boundary except for its boundary with VC33. The download might change the file type in the name from .gpx to .xml. If this happens, rename the files to .gpx. Alternatively you can download all 16 files in the zipped folder VC33_34.zip.
These track files were derived from digitised VC boundary data obtained from the NBN
The Watsonian Vice County Boundaries can be used within the terms of the OS Open Data Licence.
This can be found on the OS website (www.ordnancesurvey.co.uk/oswebsite/docs/licences/os-opendata-licence.pdf).
Contains Ordnance Survey data © Crown copyright and database rights reserved JNCC 100017955 (2003).
Disclaimer: These files are provided without any warranty of fitness for purpose. By downloading them you accept that any use you make of them is entirely at your own risk. They have been tested and used by me in one Garmin Vista HCx GPS.
Individual track files:
Zipped folder containing the 16 files:
Page created 26 November 2012 by Guy Meredith. Last revised 27 November 2012
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