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Showing posts with label Ordnance Survey. Show all posts
Showing posts with label Ordnance Survey. Show all posts

Thursday, 26 April 2012

Ye Olde Sussex


View Sussex in a larger map

If you're ever out and about recording wildlife near Gatwick, Royal Tunbridge Wells, Lamberhurst, Union Street or east of Camber - this blog post is for you!

We’re going to delve into a bit of the techie detail of wildlife recording now. But hey, what is the internet for, if not to provide more detail about everything than you ever realised you wanted to know?

Most national recording schemes work by first collating and scrutinising records at the county level and then forwarding all of this data on to a national hub, where it is amalgamated into one big national dataset, for futher analysis. This is how the Butterfliesfor the New Millenium (BNM) national butterfly recording scheme works. So I am the BNM local volunteer coordinator – responsible for pulling all the Sussex butterfly records into our Sussex sightings database – and, when I’ve managed to get the whole year’s worth of data together, I send a copy to Richard Fox - the BNM national coordinator.

But for this system to work properly and provide a comprehensive picture for the whole of the UK, we need to all agree on where the county boundaries lie. Modern county boundaries are particularly unhelpful in this regard – political whims and the ever-expanding nature of our towns and cities lead to regular boundary changes – so we don’t use those. We use Watsonian Vice Counties instead.

It’s elementary

Hewett Cotterell Watson (a man whose wikipedia entry is worth reading) devised the Vice County System of Great Britain in 1852, initially as a means of graphically representing the distribution of plants. He defined 112 Vice Counties of approximately equal areas, based on sub-divisions of counties. And it proved to be such a useful system it soon became popular for all forms of wildlife recording, as it still is to this day.

So when we talk about producing a new Sussex Butterfly Atlas - we are in fact talking about mapping the distribution of butterflies in the West Sussex and East Sussex Vice Counties, which are still identified by the numbers Watson gave them in 1852 - VC13 and VC14 respectively.

The Google Map embedded above - which you can click on to explore further - shows both the Vice County boundaries (in crimson) and the modern county boundaries (in grey). The main differences between the two are around:
  • Gatwick - which is outside the Sussex Vice Counties boundary, although it's in the modern county of West Sussex;
  • Royal Tunbridge Wells - some of which is inside the Sussex Vice Counties boundary, although the modern county boundary now traces the southern edge of the town;
  • Lamberhurst - there's a big area south of here which is inside the Sussex Vice Counties boundary, although not in the modern county of East Sussex;
  • Union Street (east of Ticehurst) - there's another big area here which is outside the Sussex Vice Counties boundary, although it's in the modern county of East Sussex;
  • Camber - there's an area east of here which is outside the Sussex Vice Counties boundary, although it's in the modern county of East Sussex; and
  • the East Sussex / West Sussex county boundary, which is in a totally different place - but you probably don't need to worry about that. 
For the Sussex Butterfly Atlas project, and the BNM national butterfly recording scheme, we are keen to know what butterflies we've got in every tetrad in the West Sussex and East Sussex Vice Counties. Helpfully, you can actually turn the Vice County ("VC") boundaries on and off in the Grab a Grid Reference website, which I was enthusing about in this earlier post. So it's easy to check if your records fall within the Sussex Vice Counties boundaries at the same time as grabbing your grid references. 

Please send us all your butterfly sightings for Ye Olde Sussex!

And if you happen to venture over the border you can find contact details for our neighbouring BNM local coordinators here - they will be happy to receive your butterfly records I am sure!


The West Sussex (VC13) and East Sussex (VC14) Watsonian Vice County boundaries are displayed under the terms of the OpenData initiative, courtesy of the National Biodiversity Network. The modern administrative boundaries for West Sussex and East Sussex are from the Boundary-Line dataset made available by OS OpenData. Displaying this data in Google Maps was more complicated that I'd bargained for, but made possible thanks to QGIS - the open source geographic information system software. Thank you internets!

Wednesday, 18 April 2012

Grid references made easy

You don't have to venture very far away from this sceptred isle to discover that Ordnance Survey (OS) deserves to be one of Great Britain's most envied institutions. I'd even go as far as to say OS maps, and the public rights of way recorded on them, are one of the greatest things about living in Britain.


OS maps - especially the Explorer series - are certainly a great tool for wildlife recording. Learning how to read an OS map is like opening an invitation to a whole new world of places to explore, right on your doorstep, where you can hunt for undiscovered populations of Dukes and Emperors. And enjoy a nice pint while you're out.

Team up an OS map with the aerial imagery provided by Google Maps, and you've got an awesome tool for wildlife recording. And that's exactly what the Grab a Grid Reference website does.  Seriously, it's awesome. It's free. And it's been developed by Bedfordshire Natural History Society out of the kindness of their hearts.


How is this useful for wildlife recording?

Grab a Grid Reference enables you to identify a place - either on the Google Maps aerial image or on the OS map - where you made your wildlife sighting. By getting the marker and moving it around on the aerial image, it will give you an accurate grid reference for that location.

It doesn't matter if you don't really understand grid references because the Grab a Grid Reference site tells you the grid reference for the location where you put your marker and shows you a coloured square outlining the area that the grid reference covers. The size and colour of the square depends on how precise the grid reference is.  The more numbers there are in a grid reference, the more precise it is.  So a two-figure grid reference (i.e. one with two numbers in it, after the two-letter prefix) describes a 10 km square.  A four-figure grid reference describes a 1 km square.  And a six-figure grid reference describes a 100 m square.

 
County Recorders like me, and your Local Record Centre, will be eternally grateful if you're able to supply your wildlife sightings with accurate grid references that are precise to 1 km or 100 m (i.e. a four-figure or a six-figure grid reference).  


But it's usefulness doesn't stop there! Grab a Grid Reference is also a really useful tool for scouting unexplored areas. Using the aerial imagery you can identify potentially suitable habitat where you might find undiscovered colonies of butterflies or other species. And you can refer to the OS map to see where the public rights of way are, enabling you to get out there and explore and survey under-recorded areas. 

As we're approaching the halfway point with our Sussex Butterfly Atlas project, this kind of approach will really help us fill in the gaps in our distibution maps and our knowledge.

Explore somewhere new this summer! And make your wildlife sightings count.