foliage

[JohnW2]

It doesn't have to be in words, an easy to relay, four-digit number would show up most errors.

Sure, one could flag the fact that there was an error by adding a numeric checksum, but it would hardly be "W3W" if it included a multi-digit number! Furthermore, as I've said, although it would identify the presence of an error is would/could not correct it.

 

[JohnW2]

Any written or spoken information can be mis-typed, or misheard. But those of us with better memories should think back - not so long ago - when the way to locate Windsor Castle was with this locator information:
51.483334, -0.604167.
I rather think that W3W is a big improvement on that!

Very much so- although, as has been pointed out, there were already other well-established 'locator systems' in existence which are also distinct improvements over lat/long numbers.

 

[JohnW2]

The mathmatics necessary to calculate the check sum would need to take acount of 40,000 words, many being homophones, the order of the words and whether words are singular or plural. very unlikely that a check sum of less than ten digits would suffice.

Indeed - and, anyway, as I've just written, to add a multi-digit numeric checksum would totally defeatthe whole concept of "W3W".

There might have been more mileage to be had in including a fourth "check word", or something like that.

 

[ericmark]

I pointed of #6 that IO82IP the maidenhead locator, which has been around for many years, allows one to give one's position accurate enough for most things, I have enough of a job, with old map references.

 

[SUNRAY]

I pointed of #6 that IO82IP the maidenhead locator, which has been around for many years, allows one to give one's position accurate enough for most things, I have enough of a job, with old map references.

But isn't that about 16 square miles?

 

[Harry Bloomfield]

Sure, one could flag the fact that there was an error by adding a numeric checksum, but it would hardly be "W3W" if it included a multi-digit number! Furthermore, as I've said, although it would identify the presence of an error is would/could not correct it.

Does it really need to correct the error? A simple, short checksum, typed in by the person answering the phone, along with the W3W, would immediately identify there was an error in the three words, or the checksum, so they ask for a repeat.

 

[JohnW2]

Does it really need to correct the error?

Not necessarily. As you go on to say ....

A simple, short checksum, typed in by the person answering the phone, along with the W3W, would immediately identify there was an error in the three words, or the checksum, so they ask for a repeat.

That would usually be fine, provided that there were adequate communication and time for a repeat to be requested and provided. That will nearly always be the case, but is not inevitably the case in some 'emergency situations. However, doing a bit of 'thinking aloud' ...

​

1... The above would work, but would obviously only serve to indicate whether or not the 'intended' three words had been communicated correctly, but clearly could not detect the correcr communication of incorrect words (e.g. ones which were not used by W3W).​

​

2... if there is a single-character error in communication of the three words then, as you suggested previously, an error could be detected by addition of a 4-digit numerical checksum. If one assigned a numerical value (0-25) to the letters of the alphabet, and simply added up the values for all characters of the words to get a checksum, a 4-digit numerical checksum would be adequate for up to 384 characters in the three words. In fact, a 32-digit numerical checksum would be adequate for up to 38 characters in the three words, which should be enough. The same would also nearly always work if there were two or more errors in the words, but (as with any checksum situation) there would then be a finite probability that the coded values for the erroneous characters would 'cancel', leading to a seemingly correct checksum despite the errors.​

​

3... a lot depends upon where the W3W has 'come from'. If it is automatically generated and displayed at the time (e.g. on the screen of a phone, tablet or watch), then the above (with the checksum) ought to work satisfactorily - detecting a transmission/communication error (in either words or checksum) in what was communicated.​

However, if the W3W (and checksum) has come from a person's memory, or from a record of it they have made themselves (on paper, in a device or whatever), then it is possible that what is remembered or had been recorded is incorrect, in which any number of 'repeat transmissions' will result in the same erroneous information (with a checksum error) being repeatedly transmitted.​

​

4... in terms of 'remembered' W3Ws, I've already observed that adding a numerical element, even if only 4 digits, would do a lot to undermine the concept of W3W​

​

5... thinking aloud even more, a fair proportion of the sort of 'incorrectly communicated' W3W words that have been mentioned could have been avoided by careful exclusion of some types of words from the W3W system, such as the avoidance of:​

plurals​

words commonly mis-spelled - e.g. if their correct spelling differed from intuitive/phonetic'expectations'​

words with 'alternative' spellings and/or pronunciations​

words with internationally-differing spellings​

etc. etc.​

Just a few thoughts!

 

[Harry Bloomfield]

5... thinking aloud even more, a fair proportion of the sort of 'incorrectly communicated' W3W words that have been mentioned could have been avoided by careful exclusion of some types of words from the W3W system, such as the avoidance ofluralswords commonly mis-spelled - e.g. if their correct spelling differed from intuitive/phonetic'expectations'words with 'alternative' spellings and/or pronunciationswords with internationally-differing spellingsetc. etc.
Just a few thoughts!

All true, but it's too late to implement now - it should have been done at the planning stage. Maybe time for a MkII, with those changes implemented?.

 

[JohnW2]

All true, but it's too late to implement now - it should have been done at the planning stage.

Yes, I've acknowledged that, more than once - as I've said, I've just been musing about "how it could have been".

Maybe time for a MkII, with those changes implemented?.

Maybe, but I suspect that any change that was not 'backward compatible' would have the potential to be more confusing than beneficial.

 

[plugwash]

At least here '999' is more likely to be dialled than '112', but then the French network would just reject that with a recorded message in French, which is probably not what you want as your house burns, or whatever.

My understanding is that mobile phones have a hardcoded list of "emergency numbers" (for a phone sold in the UK this will contain at least 999 and 112, the US emergency number 911 may also be in the list). If one of these numbers is dialed the phone will not try to make a normal call at all, but instead will make a special "emergency call".

This bypasses the normal call handling and has high priority in the network, if necessary other calls will be dropped to free up capacity for it.

 

[Harry Bloomfield]

This bypasses the normal call handling and has high priority in the network, if necessary other calls will be dropped to free up capacity for it.

It can also place the calls, via any cell network, not necessarily the one your phone is subscribed to.

 

[morqthana]

My understanding is that mobile phones have a hardcoded list of "emergency numbers" (for a phone sold in the UK this will contain at least 999 and 112,

How does it decide which number to dial?

 

[JohnW2]

My understanding is that mobile phones have a hardcoded list of "emergency numbers" (for a phone sold in the UK this will contain at least 999 and 112, the US emergency number 911 may also be in the list). If one of these numbers is dialed the phone will not try to make a normal call at all, but instead will make a special "emergency call".

Yes, I believe that is the case.

However, as I previously wrote, my understanding is that, from a landline as well as mobile phone, 112 will work in the UK (and most/all of Europe) and will connect one to the appropriate emergency service from the country from which the call was made - so morqthana's fears about "French recorded messages" are probably unfounded.

 

[JohnW2]

How does it decide which number to dial?

As I've just written, it will connect to the emergency service appropriate for the country from which the call was made.

 

[morqthana]

So how does it know which country you are in?