Ordnance survey map grid reference10/4/2023 ![]() If you enter your records online through our online recording form or through sites such as iRecord you can similarly use the map tools to generate a grid reference for you when you enter your records. All allow you to get a grid reference by clicking on a map. Our favourite sites for doing this are Grab-a-grid-reference (Bedfordshire Natural History Society), Cucaera Grid Reference Plotter, Where’s the path? and the UK Grid Reference Finder. Now there are many ways of looking up a grid reference online. This would give a more precise grid reference of NX826759 – a six-figure grid reference. So for Glen in our example the eastings would be 82 and 6 tenths and northings 75 and 9 tenths (dotted arrows). To be a little more accurate, we can estimate how many tenths along our site is for our eastings and northings. In effect, all places in the red shaded square will give the same four-figure grid reference. This is called a four-figure grid reference and is accurate to 1km. To search using British National Grid references, they can be entered into the app or online map. Excellent overhead views but appears to give coordinates based on the WGS84(ETRS89) geoid which is not what the OS uses (OSGB36). Therefore to give a grid reference we put these together by giving grid square, then eastings, then northings making NX8275. The British National Grid reference system (Ordnance Survey). Find your site again and follow the horizontal blue line directly below you site and follow this to the left or right of the page. In our example this is 82 (solid red arrow on map). Find your site and follow the vertical blue line directly to the left of the site to the top or bottom of the page. The example given here is from square NX. Be aware that some maps overlap more than one square so check carefully which square your site falls in. First we need to look up the letter of the square – an OS Landranger (pink) or Explorer (Orange/Yellow) map will give the letter in each corner of the map. Suppose we have made a record at the circle on the map. Reading the numbers from the grid combined with the letters for the 100km squares forms a grid reference. These subdivisions form the grid of lines marked on Ordnance Survey maps, and each one is numbered along the edge of the map. Dumfries and Galloway overlaps five squares – NW, NX, NY, NS and NT.Įach of these 100km x 100km squares can be further subdivided into smaller squares 10km x 10km, and these in turn are subdivided into 1km squares. In Ayrshire, all grid references fall within three squares – NR, NX and NS. Each of these are labelled with two letters, which form the first part of every National Grid Reference. The whole country is divided into squares 100km x 100km. And, if you’re in a very rural area, the nearest town, village or settlement may be some distance from where you made your sighting. ![]() But why do we need to use grid references? Surely a place name will identify the location on the map? Well in many cases it can help, but grid references allow us to be more accurate. A wildlife record is only useful if we know where the plant or animal was seen, and grid references are the best way of doing this.
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