

The 10:10 code - global position in ten characters - jgrahamc
http://blog.jgc.org/2010/06/1010-code.html

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dave1010uk
The article mentions GeoHash [1] and suggests 10:10 is better as it contains a
check digit. The advantage of a GeoHash is you can have arbitrary accuracies.
For example, if you take the GeoHash for Buckingham Pallace (gcpuuwme9mzp3)
and remove the last 6 characters (to give gcpuuwm) then the GeoHash covers a
large area of London.

[1] <http://en.wikipedia.org/wiki/Geohash>

~~~
jgrahamc
Fair enough, but that's not the use case for the code. It's designed to get
someone who's using a consumer navigation device to a location with reasonable
accuracy with high accuracy in entering the location itself.

~~~
bryanlarsen
You've said "that's not the use case" 4 times already, which is almost half
the number of comments. Perhaps this is a clue that your proposal needs a bit
of work.

That's the great thing about hacker news -- you can throw an idea at them, get
some feedback, and iterate while it's still cheap to change.

~~~
jgrahamc
Or it's an indication that people are throwing up use cases that weren't what
I was designing the code for.

For example, people have said that the ability to compare two codes is
important to see how close they are. They've said this without justification
and it is not a use case for which I designed the code.

Also, people have said that arbitrary levels of accuracy are important, they
are not needed for a navigation device being used by an individual to get to a
location.

Others have brought up the issue of using it instead of postcodes. It was not
designed for that either.

~~~
estel
But isn't it the case that a system for encoding location is more likely to be
widely accepted if it can be universally applied to a wide range of use-cases?

~~~
qntm
_Maybe wide acceptance isn't the use case!_

It's okay to intend a tool for a specific purpose! It's okay to do _one_ thing
_well_.

~~~
owenmarshall
Then the blog post should mention what it does well. In my case, I figured out
one place where it _would_ : <http://news.ycombinator.com/item?id=2674732>

This post left too many blanks, and we are trying to fill them in. If you
don't show people _why_ we should use your tool, and _why_ it is better than
the alternatives, people may not figure them out.

------
sneak
We don't need a twelfth system for encoding lat/lon tuples. Pick an existing
one and start using it.

Currently, we have:

\- decimal lat/lon

\- d/m/s lat/lon

\- UTM (
[http://en.wikipedia.org/wiki/Universal_Transverse_Mercator_c...](http://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system)
)

\- MGRS ( <http://en.wikipedia.org/wiki/Military_grid_reference_system> )

\- Geohash ( <http://geohash.org/> )

\- "Natural Area Code" ( <http://en.wikipedia.org/wiki/Natural_Area_Code> )

Please, suggesting something like this and encouraging people to implement it
is like coming out with a device that only charges over micro-USB. Just...
don't.

~~~
PieSquared
I completely agree, but was mystified by this statement...

*Please, suggesting something like this and encouraging people to implement it is like coming out with a device that only charges over micro-USB. Just... don't."

What's wrong with micro-USB? I look for it whenever I buy a new device, just
'cause all new phones, cameras, etc. use it (and only it) for charging. It's a
nice standard. No?

~~~
sneak
I said micro-USB, not mini-USB.

~~~
lambda
Yes, micro-USB is the standard which most phones, and some other devices like
the Sony Reader, conform to these days. What's wrong with that? I've never
seen another phone connector standard become as popular; before micro-USB it
was mostly proprietary connectors.

~~~
sneak
No, before micro-USB it was mini-USB, which worked great on fucking everything
from portable hard drives to Blackberries (remember those?) for years and
years.

Seriously, micro-USB is a solution looking for a problem.

------
andrewcooke
you could reduce the number of letters required without losing accuracy by
being less precise at the poles (a simple lat/lon is over-precise there
because the lines of longitude get closer together). it would require a
slightly more complex transformation, but not by much (for example, you could
make it uniform in lambert equal area -
[http://en.wikipedia.org/wiki/Lambert_cylindrical_equal-
area_...](http://en.wikipedia.org/wiki/Lambert_cylindrical_equal-
area_projection)). in other words, by taking the sine of the latitude and then
converting that to letters you can truncate more digits (because you the
resolution you need at the equator and at the poles is the same).

also, i suspect geohash could be improved by using a fractal approach like
<http://xkcd.com/195/> (<http://blog.xkcd.com/2006/12/11/the-map-of-the-
internet/>) which should reduce the need for worrying about boundaries (ie
make things more efficient).

in fact, you could combine the two.... [edit: although the fractal approach
with equal area would mean that the distances of "nearby" points changed with
latitude; it would be better to use an equal-distance projection.]

------
PaulHoule
Ham radio operators use a "grid square" code to specify locations, see

<http://en.wikipedia.org/wiki/Maidenhead_Locator_System>

this is particularly used in VHF/UHF operation where something special is
happening if you contact somebody more than 200 miles away. (Last month I
talked to somebody across Lake Ontario about 280 miles away with my handheld
thanks to a tropospheric duct.)

Grid square codes range from 4 characters to 8 depending on how detailed you
want to get. Less detailed than jgc's system, but already in use.

------
nodata
I like this idea but since it requires changing everything in the world to
deal with it, I think a better way to enter longitude/latitude co-ordinates
would be better.

Or maybe not, since search will make all of this irrelevant :)

~~~
jgrahamc
It really doesn't require much change. The major GPS vendors could support it
plus the online map services (so that's only a handful of people) and then
businesses could start publishing the 10:10 code of their location.

~~~
rmc
Loads of GPS vendors and loads of online map services isn't "much change"?

~~~
jgrahamc
Truly, it's not that much change. It would be a small update to allow GPS
devices to accept a 10:10 code and validate it, and the online mapping
services could quickly add recognizing the codes with a regexp + check the
checksum.

~~~
bryanlarsen
A small update in a well written desktop app? In the poorly written firmware
that exists on many embedded device, that's a large change.

And given that there's thousands of devices, even it was just a small change
it would be a huge massive change because of the number of places that need to
change.

------
rmc
Although that's interesting, there is a lot of advantages to a code based on
postal areas. In both cases you can find out where on earth a code _is_ , but
with a postal code you can figure out how 2 points are related, and you can
easily aggregate statistical data.

If you have 2 10:10 codes/lat lon pairs/geohashs you have no way of knowing if
they are in the same town, or are separated by a big lake. The longer the
common prefix of the 2 post codes, the more likely the 2 locations are to be
in the same place. If you're looking for "ABC 123", and you're outside "ABC
124", you're probably close.

When collecting statistics, you can ask people for the postal code, and then
aggregate the data based on where people live by just truncating the postal
code.

~~~
eftpotrm
Firstly that's specific to how a particular region encodes its postal coding,
which isn't worldwide.

Secondly, it's less true than you'd think within the UK. From
<http://en.wikipedia.org/wiki/File:London_postcodes.png>, compare the
locations of W2 and W3 or W12 and W13.

~~~
a3camero
I agree. Canada uses a concept of FSAs (forward sortation areas) that
correspond to regions. I don't think it's safe to rely on truncation under the
Canadian postal system. I believe only the first three letters/numbers
identify a geographic area, and this is the triple used by politicians and
people who need to split up regions of provinces. As you might expect, FSAs
are way smaller in major cities than out in rural areas.

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owenmarshall
Small changes to the inputs can result in dramatic changes in the output.

For example: I _know_ that (50,1.11) is pretty damn close to (50,1.12); how do
I begin to think about the distance from MEQ N6G 7RN4 to MEQ QYD 901Q?

In my mind, that's a pretty huge distance -- look how many places changed!

Not so: that's the difference between (51.0955, 1.13) and (51.0965, 1.13).
Pull that up in a map. That's a difference of, what, a hundred feet or so?

IMO, a location encoding that can't indicate at a glance that two close
locations are -- well, close -- isn't helpful.

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njl
<http://spotwoo.com/>

My weekend project a couple of weeks ago, an attempt to solve this sort of
problem. I was picking up a friend, and there was no easy way for his smart
phone to tell me where he was. So I wrote a site to let 'im. I haven't
finished testing it, but folks might be interested.

------
ignifero
If you are to make such a change, why settle for such low accuracy? What about
height/floor numbers?

Also, what about geological changes such as the japanese earthquake? thousands
of misdelivered letters...

~~~
jgrahamc
It's not designed for postal delivery. It's designed for everyday navigation.

~~~
ignifero
There are cases where navigation codes won't be more practical than postal
codes: Old cities with narrow streets and heavy buildings where GPS has no
reception. Try navigating Venice, Italy with a phone GPS to get the idea.

