Author Topic: what 3 words  (Read 5761 times)

Re: what 3 words
« Reply #75 on: November 30, 2019, 11:42:56 am »
Storage is cheap and 10Mb is neither here nor there in the days of 128Gb SD cards. Some things are worth optimising for space, some for speed.  Data of 10Mb isn't worth the time to optimise in this day and age.  Different to the 80's when I first became a professional programmer and had to optimise for programs and their data to fit into 32kB; least you wanted to invoke the joy of dynamic loading and memory swapping

Mind I'm not sure where this DB sits as I believe the translation between Lat, lon and the three words take place on their servers. So the app doesn't really need a copy.
If you don’t make time for exercise now, sooner or later you’ll need to make time for ill health.

Re: what 3 words
« Reply #76 on: November 30, 2019, 11:58:30 am »
I would have though a few tens of kilobytes would be all you would need to store the list of words.

I went back to look at https://whatfreewords.org/about.html to see how many words were in use and it's gone. Lawyers I presume.

But if we take 40,000 words as a given:-

40,000 words * average 6 letters per word = 240,000 bytes.

Compression of english text (with no words repeated) is going to be hard to get better than 50% so you're going to have 120,000 bytes minimum for storage of the words. That's way more than "a few tens of kilobytes" but still way less than 10MB.

If they ship one database with multiple languages then I can see how they can get to 10MB for the database.

Mind I'm not sure where this DB sits as I believe the translation between Lat, lon and the three words take place on their servers. So the app doesn't really need a copy.

The whole point is that the app works where you have no data connection, so the app must have everything it needs to do the conversion.
"Yes please" said Squirrel "biscuits are our favourite things."

Re: what 3 words
« Reply #77 on: November 30, 2019, 12:32:10 pm »
Ah, I thought the app didn't have the DB as the company was worried about someone reverse engineering the code to get to what is proprietary data. If it requires a data connection it's a lot less useful in remote areas where you can often get a SMS out but nothing more.
If you don’t make time for exercise now, sooner or later you’ll need to make time for ill health.

Re: what 3 words
« Reply #78 on: November 30, 2019, 01:35:46 pm »
There are only 26 letters so 1 byte per letter seems a little inefficient, both in terms of storage and search speed. Many letter pairs and triplets are frequent and a sorted listed of words have common stems. I believe it will be a few tens of kB rather than hundreds of kB and not mb. As it is produced as a one off and extra few minutes generating it seems worthwhile.

Storing data efficiently is making a bit of a comeback as datasets are getting huge and also the move to battery powered devices and transmission. Open streetmap for example uses variable bit length integers, so for example you may only use 11 bits to store a particular number and 35 bits for another. Garmin ant+ protocol is very compact because it means the sensor batteries last longer.


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Kim

  • Timelord
Re: what 3 words
« Reply #79 on: November 30, 2019, 01:50:33 pm »
Yeah, but if it's not being transmitted, it makes sense to optimise for CPU cycles required to do the lookup, rather than storage space.  A few more megabytes of storage might be a reasonable tradeoff for higher speed and a bit more battery life.
Careful, Kim. Your sarcasm's showing...

Re: what 3 words
« Reply #80 on: November 30, 2019, 03:01:29 pm »
If you are looking up a string that is half as many bytes it will be more efficient, even though for 40,000 entries it is only 16 or so comparisons to find an entry so not a lot of saving.


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Re: what 3 words
« Reply #81 on: February 12, 2020, 06:54:20 am »
https://www.theguardian.com/uk-news/2020/feb/11/ben-nevis-climbers-extremely-lucky-to-be-rescued

Quote
People see it’s called a tourist path so they think it is an easy walk up.”

Harris said there were winds of up to 100mph and windchill was causing temperatures of -20C at the summit. The group was found on steep ice near the summit, and he said going a few metres further would have posed serious risk. “They were lucky in the sense that where they were had phone signal, if it hadn’t, we wouldn’t have known they were there,” he said.

“They certainly wouldn’t have survived the night.”

The group used the what3words app to pinpoint their location.

Re: what 3 words
« Reply #82 on: February 12, 2020, 07:16:30 am »
Quote
22 members were involved in the search operation

That 3m square must have been getting pretty full.

Re: what 3 words
« Reply #83 on: February 12, 2020, 07:28:46 am »
The cracked version has been taken down.  Boo.

Google Maps, which nearly all phones will have, will show your ICBM address with a long press (and no need for an Internet connection), so W3W is completely pointless.
Never tell me the odds.

Jaded

  • The Codfather
  • Formerly known as Jaded
Re: what 3 words
« Reply #84 on: February 12, 2020, 07:34:24 am »
It isn’t completely pointless. It’s point is to try and make money for the developers.

Hopefully phone OS manufacturers will develop a system that, with a smile push of a button, or click, (like emergency calling) sends a proper location in a universal format, and puts.the.sword to W3W
If you don't like your democracy, vote against it.

Re: what 3 words
« Reply #85 on: February 12, 2020, 08:14:10 am »
It isn’t completely pointless. It’s point is to try and make money for the developers.

Hopefully phone OS manufacturers will develop a system that, with a smile push of a button, or click, (like emergency calling) sends a proper location in a universal format, and puts.the.sword to W3W
You mean like AML?

https://en.wikipedia.org/wiki/Advanced_Mobile_Location
<i>Marmite slave</i>

Re: what 3 words
« Reply #86 on: February 12, 2020, 08:27:30 am »
They were foreign students with broken English. It was pure chance that their description of what happened “affair.enter.skid” identified the 3m square in the frozen gully where they were found.


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Jaded

  • The Codfather
  • Formerly known as Jaded
Re: what 3 words
« Reply #87 on: February 12, 2020, 09:41:19 am »
It isn’t completely pointless. It’s point is to try and make money for the developers.

Hopefully phone OS manufacturers will develop a system that, with a smile push of a button, or click, (like emergency calling) sends a proper location in a universal format, and puts.the.sword to W3W
You mean like AML?

https://en.wikipedia.org/wiki/Advanced_Mobile_Location

If that is available from a lock screen, and can be sent semi automatically with one hand, whatever the OS of the phone, yes.
If you don't like your democracy, vote against it.

Re: what 3 words
« Reply #88 on: February 12, 2020, 09:54:48 am »
It isn’t completely pointless. It’s point is to try and make money for the developers.

Hopefully phone OS manufacturers will develop a system that, with a smile push of a button, or click, (like emergency calling) sends a proper location in a universal format, and puts.the.sword to W3W
You mean like AML?

https://en.wikipedia.org/wiki/Advanced_Mobile_Location

If that is available from a lock screen, and can be sent semi automatically with one hand, whatever the OS of the phone, yes.
But what if there was no mobile signal as is often the case in the mountains and the one with suitable footwear had to abandon the other three at affair.enter.skid to go in search of rescuers or a mobile signal ?


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Re: what 3 words
« Reply #89 on: February 12, 2020, 10:03:39 am »
How about: read.before.posting

Every time this thread is bumped with a new story (no problem with that) the same things (lack of signal, GPS coordinates can be used anyway, AML, GPS drift due to plate tectonics, everything else brought up by Terence Eden, etc) that have already been discussed get brought up again and again.

But what if there was no mobile signal as is often the case in the mountains and the one with suitable footwear had to abandon the other three at affair.enter.skid to go in search of rescuers or a mobile signal ?

In this scenario remembering three words (assuming you had nothing to write them down on, physically or electronically) might be slightly easier than remembering some GPS co-ordinates to sufficient precision[1] to be useful, but that's a considerable number of 'what ifs' that need to all occur at the same time. Also risky given the possibility of mis-remembering them at the end and the fact that any error results in the co-ordinates being useless.

1. 4 decimal places with ref to https://xkcd.com/2170/
"Yes please" said Squirrel "biscuits are our favourite things."

Re: what 3 words
« Reply #90 on: February 12, 2020, 10:45:52 am »
It worked. The emergency services, mountain rescue in particular seem to like it. It has a lot of redundancy. Just 2 of the words and in the wrong order and the fact you were on Ben Nevis would have worked too. Just one of the words and that you were near the summit. It is annoying that it is proprietary but that does not detract from the idea. It can also be used over radio, a speech interface on the garmin gpsmap64 to save having to take gloves off and it would be even better.


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fuaran

  • rothair gasta
Re: what 3 words
« Reply #91 on: February 12, 2020, 11:03:42 am »
It worked. The emergency services, mountain rescue in particular seem to like it. It has a lot of redundancy.
Some mountain rescue teams like it, others have said it is a terrible idea. Are they being sponsored to promote it?

Quote
Just 2 of the words and in the wrong order and the fact you were on Ben Nevis would have worked too. Just one of the words and that you were near the summit.
How do you figure this out? Do they provide any way of searching for a single part of the code?
There are thousands of possible locations nearby, it will take a while to look up and compare the code for each one. Unless you had access to the API, but What3words might charge for that sort of thing.

Re: what 3 words
« Reply #92 on: February 12, 2020, 11:17:18 am »
The api is free for use in not for profit, so for example mountain rescue do not have to pay if using it directly themselves. Commercial software being sold to emergency services would indeed have to pay for the use so if mountain rescue was purchasing software with this facility it would be more expensive than if it didn’t.


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fuaran

  • rothair gasta
Re: what 3 words
« Reply #93 on: February 12, 2020, 11:26:40 am »
How do they decide what is "not for profit" and what isn't? And what if they start charging a lot more for the API in the future?

Re: what 3 words
« Reply #94 on: February 12, 2020, 11:34:05 am »
Ah, then mountain rescue might have to start charging, which would be unfortunate or go back to what12digits.


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Re: what 3 words
« Reply #95 on: February 12, 2020, 11:37:11 am »
Quote
Just 2 of the words and in the wrong order and the fact you were on Ben Nevis would have worked too. Just one of the words and that you were near the summit.
How do you figure this out? Do they provide any way of searching for a single part of the code?
There are thousands of possible locations nearby, it will take a while to look up and compare the code for each one. Unless you had access to the API, but What3words might charge for that sort of thing.

On the website you can move the map around to see what individual squares are called. If you know they are in a certain area (based on description) then searching around for suitable words is possible but it would be a manual task prone to error.

Knowing they are within 200m of a certain point would mean you've got a bit more than 400 3x3m squares to check. One every 2 seconds and that's somewhere around 15 minutes work.
"Yes please" said Squirrel "biscuits are our favourite things."

Kim

  • Timelord
Re: what 3 words
« Reply #96 on: February 12, 2020, 11:56:39 am »
What 3 Words isn't a solution to unprepared people getting stuck on mountains because, just like everything else, it requires a level of preparedness.
Careful, Kim. Your sarcasm's showing...

Re: what 3 words
« Reply #97 on: February 12, 2020, 12:56:16 pm »

Re: what 3 words
« Reply #98 on: February 12, 2020, 01:03:17 pm »
Really?  You must be in one of the nearby offices?  ;)

Re: what 3 words
« Reply #99 on: February 12, 2020, 01:33:19 pm »
I was waiting for a train.   I'm now in Coventry waiting for a train ...