The maps below provide Ordnance Survey grid references and a range of site boundaries for use with surveying and recording wildlife in Gloucestershire. To grab a grid reference, drag the red marker on the left-hand (Google) map to wherever you want the reference. Alternatively, pan the left map to where you want and click the "Get the marker" button above. The grid reference for the position of the red marker will appear in the grey box below. The corresponding size and colour of grid square is drawn on both maps. Tick your choice(s) of grid reference from the grey box. Note that the grey box also has a full digital Easting/Northing option, plus a Lat/Long option, for checking e.g. against GPS readings. Click the "about grid references" button for more information.
Optional: on devices with GPS and newer browsers - e.g. smartphones - you may be able to use the device's built-in GPS location. Check out the using geolocation button below for more details.
Clicking on "Get the marker" will bring it to the centre of the map. If you pan away from the marker, click "Go to marker" to get back to it. Note that the blue marker on the right-hand (Ordnance Survey) map is simply there to track the red marker - it cannot be dragged.
Additional boundary layers can be turned on and off using the tick boxes under the left-hand map. Note that the more detailed layers may load slowly and take a while to appear, especially on older systems or slower internet connections.
The right-hand map copies the position of the left-hand map whenever it is zoomed, panned or the marker moves, but the right map can be can be zoomed and panned on its own. If you've found the place you wanted using the right-hand map, you can move the left map to it using the "Match Left Map to Right Map" button underneath.
The Search for: box can be used to search for locations, either by a Grid reference (e.g. SC340959), postcode (e.g. IM5 1AU), or a placename - but note that it currently goes to the first matched placename rather than a choice, so you might prefer to use postcodes where available.
Grab-a-Grid-Reference has been tested on a range of browsers and found to work well on all except earlier versions of Internet Explorer (v9 and earlier) and "lightweight" mobile browsers. On these, the maps are usually functional but the site layout may be a bit sketchy-looking.
(click the "add map layers" button again to hide this section)
OS Grid References
The grid references below mark the position of the colour-coded grid square around the red marker on the left-hand map.
Drag the marker to where you want the reference, or centre the map on the desired place and click "Get marker".
Click on the geolocate now button to centre the Google map on your current location. Click on Get marker to centre the marker and show the grid reference.
If you haven't done this before, a box will come up, either asking you to share your location,
or asking about Google's Location Services, or similar.
It's important to note that only a good built-in GPS is worth using to get a grid reference. Location Services will work even on computers with no GPS, but only by locating your Internet Provider or IP address. Whilst this can be very accurate, it might just centre the map in the town where your IP is located!
Even a good GPS can be inaccurate if the signal is weak or non-existent, so always check the marker location carefully before using an automatic geolocation to get a grid reference! You may need to drag the marker a bit to get a true position, especially where GPS signals are poor.
This site uses the same geolocation feature familiar to users of Google Maps on smartphones and tablets. You may need to allow location access before it will work. Not all mobile browsers will read automatic geolocation. You may need to experiment with which mobile browser gives the best performance on your phone or tablet.
Most online maps do not use an Ordnance Survey grid system, as it only applies to the UK - whereas they need a global projection similar to that used by GPS devices. By using sites such as Grab-a-Grid Reference it is possible to use the web maps but also get converted UK coordinates, accurate to within a few metres.
OS grid references are entirely grid-based; thus, a reference is for a square, not a point as such. This needs to be borne in mind when looking at "point" grid references plotted on a map. The size of the square - e.g. the commonly-used 100mx100m 6-figure grid reference - relates to recording accuracy and purpose.
Experienced recorders avoid artificially detailed references (e.g. 12-figure coordinates, apparently accurate to 10cm, taken from a GPS where the record itself is really for a whole field). Likewise, 2km and 10km square grid references are too vague for most local recording purposes. Such references are, however, useful for atlas distribution maps and large-scale systematic surveys.
GCER recommends using a 6-figure or 8-figure grid reference for local sightings wherever possible.
The Ordnance Survey website has a useful page of information and FAQs about their national grid system here.
For those wanting to use these maps further afield: although the OSGB National Grid covers a portion of Ireland, Irish grid references are usually given using a different system. Irish grid refs can be obtained here.
Tick or untick the extra map layers as required. Click on the map features to get a brief name, area or description. Some features also have links to websites with more information. Note that the most recently-ticked layer is the "top" layer: if the top feature obscures the layer underneath, clicking on it will get you information for the top layer only.
Administrative boundaries are from Ordnance Survey OpenData sources; they are free to use but may not have perfect accuracy when zoomed in close.
The Nature Map layer shows Gloucestershire's Strategic Nature Areas (SNAs), identified using the Rebuilding Biodiversity in the South-West methodology. The layer is maintained by GCER. SNAs provide one of the scientific foundations for choosing effective target areas for conserving and restoring important ecological networks. Click on each SNA on the map to see its name, area and a link to the Gloucestershire Nature Map website.