Grab a Grid Reference...
Mono version HERE
Checking tile count...
Lock zoom level of OS map
Drag the red marker on the left map to where you want a National Grid reference*. (The blue marker on the right map cannot be dragged). The grid refs will appear on the right, and the corresponding boxes are drawn on both maps.
Please do not record wildlife using 2km, 5km or 10km grid refs as they are too vague. These are for information only.
On the left map press "Satellite" for aerial photos only, or "Map" for Google Maps only.
The Vice-counties, VC30 and Bedfordshire boundaries only show on the left map (at present...)
The right map shows Ordnance Survey (OS) maps of different scales according to the zoom amount. (OS limits the number of map tiles accessed to 100,000 per day, so the right map will stop working if this is reached).
The right map tracks the left map whenever it is zoomed, panned or the marker moves, but the right map can be can be zoomed and panned on its own. The zoom level of the right map can be locked to its current level so that it doesn't change when the left map is zoomed. Just tick the box under the OS map. (The OS zoom can still be changed manually of course).
If you've found the place you wanted using the right map, you can move the left map to it using the "Match Left Map to Right Map" button.
The "Get The Marker" button moves the marker to the centre of the left map, so match the maps first.
Bookmarking: Due to differences between browsers as to how they support bookmarks I have abandoned the previous method. The following is now the best way:
Append "?gr=XXXXXX" to the GAGR web address, replacing XXXXXX with your desired gridref, e.g. https://www.bnhs.co.uk/2019/technology/grabagridref/gagr.php?gr=TL123456 will go to TL123456, then use your browser's normal bookmarking method to remember it for future use. (Remember to actually "go to" each newly created web-address containing a new gridref otherwise your browser will just bookmark the previous address again).
The "Go to ..." box can be used to go to a Grid reference (e.g. TL123456), or a postcode e.g. (MK41 9DJ), or a place name. (Currently it goes to the first matched place name, but a choice may eventually be offered - bear with us).
The "Toggle Vice-County" selector turns a Vice-County boundary on and off each time that county is selected. NOTE: It takes a while to download to your PC the large files defining some VCs, so you may see a significant delay before a boundary appears - please be patient. Multiple VCs can be displayed. If you want to clear all the VCs, select the second option "Clear Vice-Counties". Clicking on a boundary will tell you which VC it is.
GAGR fits to the browser's window size when started. If you subsequently change the browser window size you can re-fit GAGR to it using the "Fit to Window" button (top-left).
Accessible Wildlife Site (AWS) and Roadside Nature Reserve (RNR) boundaries courtesy of the BRMC which maintains them. Note that these boundaries are intentionally only approximate and should NOT be treated as definitive site boundaries.
You can add layer(s) contained in a KML or KMZ file to the left hand map (e.g. if you want to show your own site boundaries or to display some mapped information). Enter a web address for a KML or KMZ file into the text box next to the "Add KML/KMZ" checkbox, then tick the box to add the layers to the left map. Try pasting https://www.bnhs.co.uk/technology/google_earth/maponge/Example Dataset.kmz into the text box to see an example produced using our Map Your Records tool. (The example will show squares and markers in the central Bedfordshire area).
The "mono" map version of this tool (Google maps only) can be accessed HERE if you prefer it.
* as defined on Page 35 of A Guide to Coordinate Systems in Great Britain
(Although the National Grid covers a portion of Ireland Irish grid references are usually given using a different system. Irish grid refs can be obtained here)
Want to plot a set of records on Google Earth? Use our simple interface HERE
Special permission was sought and obtained from the NBN Trust to make the vice-county boundaries available on Google Maps. This has been granted for individual use and non-commercial purposes ONLY. We are required to say that digital VC boundaries were developed under contract and funded by Defra, Scottish Natural Heritage and the NBN Trust, and to display the following.
Digital Watsonian Vice-County Boundary Data© National Biodiversity Network Trust and Crown Copyright 2003 All rights reserved
Comes with ABSOLUTELY NO WARRANTY.
Note to webmasters:
Basic instructions for including the code within a website have been provided HERE.
We are pleased to report this tool is being adopted by other webmasters and can also be found at:
Warwickshire Butterfly Conservation
Please email Webmaster if you also adopt it.