All longitudes are measured from the Greenwich Meridian (also known as the Prime Meridian), which runs through (unsurprisingly) Greenwich, in London, England. The Greenwich Meridian is the line of zero longitude, although it has been moved around a little by various people and their datums...
Along its length, many signs and markers exist to show interested passers-by that the Greenwich Meridian lies here, letting people know when they pass from the eastern to the western hemisphere (or vice versa).
Your challenge, should you choose to accept it, is to find a marker or sign denoting this meridian, and take a photograph of it to post here. Ideally, two photographs. One of the sign, and one of your GPS in front of the sign, showing your co-ordinates.
Note: The Greenwich Meridian is defined in several ways, according to the map datum used. There's OSGB, WGS84, NAD27, and a whole host of others. Their locations of where zero degrees longitude differ slightly (by up to a hundred metres east or west). The WGS84 datum, for example, will often show the Meridian markers to be about 100 metres west of 0°0.00' in the UK, because the sign or marker was placed there using the OSGB (Ordnance Survey Great Britain) map datum.
So don't worry too much if the marker you find doesn't appear to be on the Greenwich Meridian! It'll be interesting to see the range of longitudes at these signs, and the different data people can report their co-ordinates back in - see if you can switch to the right datum with your unit to get all those lovely zeroes. Please post the datum your GPS is set to when you took the photo.
For example:
The lower image shows that the WGS84 datum reckons the OSGB Meridian marker to be 5.8 seconds west.
Rules:
- Each marker/sign can be logged only once - I have included shots of the sign near Royston (and near "Scooby Doo") so no-one else can have that (Sorry Subarite!)
- Each cacher may only log one marker as a 'find'. Subsequent markers may be logged as notes.
- Make sure to post a photograph of the GPS, showing the co-ordinates
- Logs MUST inlude the datum that the GPS receiver was set to - the datum and co-ordinates are pertty much the whole point of this cache!
- Clarification: I want photos of the sign that is (or claims to be) on the Meridian. Signs or maps that show where the Meridian runs, but that aren't actually on it, don't count!
Any posts that don't follow the rules are liable to be deleted!
Further Clarification: I want signs that are associated with the Greenwich Meridian! Posts logged for locations further than 0.5 degrees east or west of the Greenwich Meridian will be (and have been) deleted!
Happy Hunting!