Specifying the Starting Point, Meeting point or Finishing point.
When entering a place in the Submit Walks Form it is easy to generate confusing and conflicting information.
Basically there are four ways to specify a location. :-
- Latitude / Longitude
- OS Grid Reference
- What 3 Words
- Post Code.
Post code should be avoided if at all possible because postcodes can cover a large area.
Latitude and Longitude are not really very user friendly though they are used by Navigation aids like Google maps and Sat nav devices. Although you would typically give them a Postcode.
The OS grid Reference has been used historically to provide a way to pin point a place on an OS map. However, Google Maps and other navigation aid typically don't permit the use of an OS Grid Reference. The Grid reference is typically estimated and given as a six digit number and has an accuracy of 100 metres. Thus it covers an area of 100,000 square metres.
What3Words is a recent method of specifying a location and is far more accurate than the OS Grid Reference since each combination of three words only covers 9 square meters. In essence a What3Words location can only be accurately be derived from the What3Words app.
It is possible to convert an OS Grid Reference or a Latitude Longitude by using a number web sites. However, care must be taken when using these sites.
If you have located a place using the What3Words app for example ///flats.remedy.friday we have a very accurate location.
For the rest of this discussion I will be using results from
If we convert ///flats.remedy.friday to a OS Grid Reference and Postcode:-
https://streetmap.co.uk/ returns:-
Grid Reference SU645714 / SU6456571444
Nearest Post Code RG7 5AR
https://gridreferencefinder.com returns:-
Grid Reference SU645714 / SU6456571444
Nearest Postcode RG7 5AR
https://www2.pvramblers.org.uk
Grid Ref: SU645714 [SU64567144]
Notice: our web site only provides the six digit and the eight digit grid references.
As noted above the six digit is accurate to 100 metres. The eight digit grid reference is accurate to ten metres and the ten digit grid reference is accurate to one metre.
So these three case all three agree that the What3Words are ///flats.remedy.friday
Now if we attempt to reverse the operation using the grid reference SU6456571444
We get the same results from all sites.
However, if we only use the grid reference SU645714 we get very different results.
streetmap.co.uk
Grid Reference SU645714 / SU6455071450
Nearest Post Code RG7 5AL
what3words bleak.echo.dance
Grid Reference SU645714 / SU6450071400
Nearest Postcode RG7 5FW
what3words almost.foods.hogs
www2.pvramblers.org.uk
Location: Lat 51.4379/ Long -1.0734
Grid Ref: SU645714 [SU64507140]
What 3 words: almost.foods.hogs
You will see both gridreferencefinder and our website agree on What3Words
However streetmap gives What3Words as ///almost.foods.hogs
The reason for the differences is that streetmap.co.uk uses ’50’ to pad out to the 10 digit grid reference where as gridreferencefiinder.com uses ’00’
www2.pvramblers.org.uk only pads out to eight digits with a ‘0’.
Thus the streetmap.co.uk position is 50 metres north and 50 metres east of the gridreferencefinder.com position.
You will note also that there are differences in the post codes though they are all postcodes for High Street Theale.
When the walk is submitted to Walks Manager the Grid Reference SU64567144 is used.
The resulting Starting position in walks manager is:-
Grid reference: SU 64560 71441
Nearest postcode: RG7 5AL
what3words: goal.spices.resort
So which of these is the correct one to use? In truth it doesn’t really matter. They’re all pretty close together.
The Submit-Walk form will accept a grid reference of any length or What3Word If you really have no alternative then you can use a street address or Postcode.
If you have estimated the six digit grid reference using an OS map or have taken it from a previous walk that started in the same place. Then use that six digit grid reference.
If you have obtained a grid reference for an app such as the OS Map App use the ten digit grid Reference.
If you use the What3Words app use the location it gives you.
If you are using an app that gives you a Latitude/Longitude use https://gridreferencefinder.com
If at all possible avoid using a Street Address or postcode they are simply too unreliable.
Do not attempt any sort of conversion from say What3Words to a grid reference or a grid reference to a What3Words
Please avoid putting a What3Words location in the description since it will more than likely differ from the one generated in Walks Manager.