[okfn-labs] opening up what3words
Maurizio Napolitano
napo at fbk.eu
Mon May 18 08:56:16 UTC 2015
from my point of view, a good solution may be to create a grid using
the same method by using TMS - Tile Mapping Service.
This is the same method used by OpenStreetMap, Google Maps and a lot
of different webmapping providers\
I a TMS you have differents kind of "floor" (each floor is a a zoom level).
In this case I think, can be usefull use a zoom level 22 or more (the
right number to have a tile of 3x3 meters or less).
I suggest you to have a look here
http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
With a TMS you identify a single tile with 3 number: zoom level, row and column.
The projection used is the "Google Web Mercator"
https://en.wikipedia.org/wiki/Web_Mercator
but from the tile is possible transform in WGS84 (lat/log) coordinates
The solution has some mistakes: but this is a with the projections!
look here
https://en.wikipedia.org/wiki/Web_Mercator#Advantages_and_disadvantages
In my point of view:
- it's impossible have a complete coverage of the world
- the solution can forget the the cases of North and South pole, or
create another solution for this cases
- have a perfect precision is a big challenge: better concentrate to a
solution with a reasonable error of precision (from ~5 meters). The
precision depends on the use.
If ask you "Where is London?" You don't need to have a perfect
precision. It's always a big discussion define which is the point to
describe a city: the main square? the downtown? the main building? the
main symbol of the city? the social barycenter? ....
Other case if I ask "Where is the headquarter of the OKFNlab?" maybe I
need to know where is the building or the main entrance ...and so on.
- onece created the grid, I suppose that, later is "easy" have a
dictionary like what3words.
Maybe by using some data like multiwordnet -
http://multiwordnet.fbk.eu/english/home.php (cc-by license) and have a
multi language "what3words" to give a name of each cell.
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