5 ms·

I'm a little confused about what this replaces, but it's definitely not postcodes. * Postcodes have a specific meaning: they're both a geographical area and a

by jxf 12y ago

I'm a little confused about what this replaces, but it's definitely not postcodes. * Postcodes have a specific meaning: they're both a geographical area and a mail delivery zone (at least in the US). Replacing one short code with another, which requires a different and less reliable third-party service to correctly decode, doesn't seem like a good idea. * Latitudes and longitudes are unambiguous, well-understood, and don't require a third-party service to be online in order to correctly decode. So it doesn't seem like this can replace latitudes/longitudes, unless we're talking about shortening their representation. * Broadly speaking, while addresses have a lot of problems, they're unambiguous with human context. So this doesn't seem like it really replace addresses either. * For things like a loose description that might not be associated with a single point (e.g. "Central Park"), I could see mapcodes being useful -- you can provide the precise boundaries of the park, where it's located, associate metadata with the mapcode like what hours the park is open, etc. That might be very helpful. Also, won't there be multiple mapcodes for a single spot and won't that require cross-association of the respective metadata? For example, consider that Central Park is also in Manhattan, also part of NYC, also in Midtown in NYC, etc. I guess that's not necessarily a problem, but it could lead to a lot of expensive processing for frequently updated locations/boundaries (e.g. a beach, a suburban development in progress, etc.).

diydsp 12y ago
> latitudes/longitudes, unless we're talking about shortening their representation. That's a much smarter idea than this mapcode system. It would make sense to replace the base-10 representation with base 36.... at least in the Roman alphabet. It would probably be smarter to pick a base that works with the world's alphabets. Oh yeah, not all the world uses alphabets! But even then, it's not that huge of an improvement, really! Every two digits of base 36 replace three digits of base 10. (36^2 = 1296). The b36 digits replace only 4 (or 4.5) base 10 digits. 4x b36 digits replace 6 base 10 digits. I think this may actually just be the Ham radio grid system I mentioned elsewhere. > For things like a loose description that might not be associated with a single point (e.g. "Central Park"). Here, I could see mapcodes being useful -- you can provide the precise boundaries of the park, where it's located, associate metadata with the mapcode like what hours the park is open, etc. Heh, at this point, I'm just thinking "URL". After all, it's a Universal resource locator. How about mapcode://CentralPark/my_favorite_bench.
- lstamour 12y ago
  From their developers' doc: > Mapcodes can be easily translated between several different alphabets. The default system is based on the roman alphabet. Mapcodes in other alphabets are generated by character substitution. And it's not based on representation of lat/lng, which is why it's more of an improvement: > As explained in the previous section, by reserving short codes for the most densely populated areas, mapcodes for addresses (i.e. places that people need to visit) are on average as short as theoretically possible, within the limits we set for ourselves. One such limit is to use only rectangular areas in our definitions. Another is to limit the size of the “context” data table to about 16,000 records. Probably the most relevant design choice was the choice of character set. For example, had we allowed both capital and lowercase letters, 3 times as many people could have 5-letter codes instead of 6-letter codes. > The mapcode system allows about 100 km2 of a territory to be covered by 4-letter mapcodes. These are usually reserved for the capital city. About 6,000 km2 can be covered by 5-letter mapcodes . Roughly 250,000 km2 can be covered by 6-letter mapcodes. If a territory is larger than that, the remainder requires 7 letters. A few territories on Earth (notably, Australia, Brazil, Canada, China, India, Mexico, Russia and the USA) are large enough to merit 8 letters, but these actually consist of sub-contexts, i.e. people there live in a state, republic or oblast much like people elsewhere live in a country. Within such a sub-context, mapcodes are shorter.
  - digikata 12y ago
    Between this, and discussion of hardcoded magic values in lookup tables in the code, I wonder about how future population/geography shifts will be handled. It's not a dealbreaker, but it seems like a technical cost of interpreting mapcodes would be periodic required updates of the translation codes.
deleted 12y ago
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Alupis 12y ago
Their own website is displaying/using MapCode's incorrectly. For example, they have 0C.T4 and they say it's in Ireland and appears to be some bench in the picture. However, if you use that MapCode, you will see it's the middle of some river in Amsterdam. 0C.T4 == 52.369764, 4.868898 Another: 81.J4W They seem to claim it's in Alaska, appears to be some road. However, it's another river in Amsterdam. 81.J4W == 52.508957, 4.769173
- nandhp 12y ago
  The shorter MapCodes are within the context of a specific country, but the "I have a MapCode" box defaults to the Netherlands. If you change that to Ireland, it's 0C.T4 is in the middle of a park near Dublin.
- opium_tea 12y ago
  Mapcodes also have to be combined with some context. In most places it's just the country name, but in large countries it also requires the state (or equivalent). So if you go to the interactive map on the mapcodes site, there's a little link marked context and you need to change that to Ireland. Results in this: http://www.mapcode.com/getcoords.html?iso3=125&mapcode=0C.T4&xx=-6.271020&yy=53.347424 http://www.mapcode.com/getcoords.html?iso3=125&mapcode=0C.T4...
  - Alupis 12y ago
    So, they want to throw out the old coordinates system (which was absolute location regardless of any "context"), with a system that if you loose the context information, or misinterpret it, you can wind up in a very wrong location? I've written a fairly extensive GPS library for some embedded device projects in the past, and I can attest to the computer not caring about the long coordinate system, they are just floating points really.
- deleted 12y ago
  [deleted]
- apoorvai 12y ago
  I think you need to change your "context" country. If I look for 0C.T4 in Ireland, I see green (implying a bench). It looks like the mapcodes are country specific, and two countries can have the same mapcode.
jib 12y ago
Yep. Swedish post codes define mail delivery areas as well. You can effectively sort on partials and get high accuracy. For instance, the office I used to work in handled all of 421xx, 426xx and 436xx, as well as a few of the 430xx range. Sorting was done by bucket sort (literally) on the top 3 digits in a central distribution location (all 5 for those like 430xx that was handled out of several offices), then distribution to each mail office, then another bucket sort on the full five digits, followed by another bucket sort on (roughly) street address, followed by a final sort on route. This appears to lose all of that functionality.
6d0debc071 12y ago
From the Mapcode System Reference Document: http://www.mapcode.com/downloads.html http://www.mapcode.com/downloads.html 'Unfortunately, a large part of the world population has no address. In India alone, well over half a billion people live in houses that have no street name. Millions of man-hours are lost every day trying to locate or deliver goods to people and businesses based on business cards like this: ------------------------------------------------------ Amri Patel, consultant New Sun Technologies, District 14, Pune Tel. +23984982217 Three miles east along the airport road, take second left past the golden statue, in the fourth street left ask final directions at baker across from white house. Figure 1. Typical Indian Business Card ------------------------------------------------------ As we all know, even having an address is only an initial step in locating a position. Knowing someone lives on Queens’ Road 123 in Brunnock still requires you to find out where Brunnock is, and where the Queen’s Road is, and where number 123 is. The mapcode system was designed as a free, brand-less, international standard that allows any location on the surface of the Earth to be represented by a short, easy to recognize and remember “code”, usually consisting of between 4 and 7 letters and digits.' So, your point number 2 seems closest to what they're aiming for. Indeed, later in the document, they state: 'The longer a code gets, the more awkward it becomes to use, the more difficult to remember, the more easy to make mistakes in copying or using, the less benefit it offers over more elaborate descriptions. Many other benefits depend on mapcodes being short. If length was not a problem, we might as well put our longitude and latitude on business cards and address labels.' > Also, won't there be multiple mapcodes for a single spot and won't that require cross-association of the respective metadata? It seems like this corresponds to a coordinate system. You say what country you're in and then this gives you an aim point. I don't think you need to say 'it's in This, which is in This which...' :/
jofer 12y ago
> "Latitudes and longitudes are unambiguous..." This is a tangent, but actually, they're not. There have been (oil) wells fail because someone gave a lat/long without specifying the datum, and someone else assumed it was in a different datum. Without a datum defined, latitude/longitude (no matter how precise) only gets you to within ~1km of an actual location. The Earth is not a sphere (or even an ellipsoid). Therefore, we need models of the the absolute shape of "sea level" (i.e. an equipotential surface - varies due to density variations in the Earth) to go from a spherical coordinate system to an actual point on the Earth's surface. These are referred to as a datum. Because our knowledge of the absolute shape of the Earth has changed over time, there are many different datums (ranging from spheres to ellipsoids to detailed gridded surfaces). There are a large number of datums that are still in common use. WGS84 is the most common (and very accurate), but NAD83 and NAD27 are also very, very common, as well as many others. If someone gives you a lat/long in NAD27 (e.g. read off of a printed map) and you assume it's WGS84, you can wind up over a kilometer away from the original location. (NAD27 is reasonably accurate for the US, but is very inaccurate elsewhere on the planet. I regularly see it used for data everywhere, though.)
- kghose 12y ago
  Thanks for teaching me about datums: http://en.wikipedia.org/wiki/Datum_(geodesy) http://en.wikipedia.org/wiki/Datum_(geodesy)
- jxf 12y ago
  You're absolutely right, and I should have said that! I was trying to contrast to the case of just typing it into some kind of map service, i.e. MapCodes. A lat/long pair unambiguously resolves to a single point in that service.

by jxf 12y ago

diydsp 12y ago

> latitudes/longitudes, unless we're talking about shortening their representation. That's a much smarter idea than this mapcode system. It would make sense to replace the base-10 representation with base 36.... at least in the Roman alphabet. It would probably be smarter to pick a base that works with the world's alphabets. Oh yeah, not all the world uses alphabets! But even then, it's not that huge of an improvement, really! Every two digits of base 36 replace three digits of base 10. (36^2 = 1296). The b36 digits replace only 4 (or 4.5) base 10 digits. 4x b36 digits replace 6 base 10 digits. I think this may actually just be the Ham radio grid system I mentioned elsewhere. > For things like a loose description that might not be associated with a single point (e.g. "Central Park"). Here, I could see mapcodes being useful -- you can provide the precise boundaries of the park, where it's located, associate metadata with the mapcode like what hours the park is open, etc. Heh, at this point, I'm just thinking "URL". After all, it's a Universal resource locator. How about mapcode://CentralPark/my_favorite_bench.

lstamour 12y ago
From their developers' doc: > Mapcodes can be easily translated between several different alphabets. The default system is based on the roman alphabet. Mapcodes in other alphabets are generated by character substitution. And it's not based on representation of lat/lng, which is why it's more of an improvement: > As explained in the previous section, by reserving short codes for the most densely populated areas, mapcodes for addresses (i.e. places that people need to visit) are on average as short as theoretically possible, within the limits we set for ourselves. One such limit is to use only rectangular areas in our definitions. Another is to limit the size of the “context” data table to about 16,000 records. Probably the most relevant design choice was the choice of character set. For example, had we allowed both capital and lowercase letters, 3 times as many people could have 5-letter codes instead of 6-letter codes. > The mapcode system allows about 100 km2 of a territory to be covered by 4-letter mapcodes. These are usually reserved for the capital city. About 6,000 km2 can be covered by 5-letter mapcodes . Roughly 250,000 km2 can be covered by 6-letter mapcodes. If a territory is larger than that, the remainder requires 7 letters. A few territories on Earth (notably, Australia, Brazil, Canada, China, India, Mexico, Russia and the USA) are large enough to merit 8 letters, but these actually consist of sub-contexts, i.e. people there live in a state, republic or oblast much like people elsewhere live in a country. Within such a sub-context, mapcodes are shorter.
- digikata 12y ago
  Between this, and discussion of hardcoded magic values in lookup tables in the code, I wonder about how future population/geography shifts will be handled. It's not a dealbreaker, but it seems like a technical cost of interpreting mapcodes would be periodic required updates of the translation codes.

deleted 12y ago

[deleted]

Alupis 12y ago

Their own website is displaying/using MapCode's incorrectly. For example, they have 0C.T4 and they say it's in Ireland and appears to be some bench in the picture. However, if you use that MapCode, you will see it's the middle of some river in Amsterdam. 0C.T4 == 52.369764, 4.868898 Another: 81.J4W They seem to claim it's in Alaska, appears to be some road. However, it's another river in Amsterdam. 81.J4W == 52.508957, 4.769173

nandhp 12y ago
The shorter MapCodes are within the context of a specific country, but the "I have a MapCode" box defaults to the Netherlands. If you change that to Ireland, it's 0C.T4 is in the middle of a park near Dublin.
opium_tea 12y ago
Mapcodes also have to be combined with some context. In most places it's just the country name, but in large countries it also requires the state (or equivalent). So if you go to the interactive map on the mapcodes site, there's a little link marked context and you need to change that to Ireland. Results in this: http://www.mapcode.com/getcoords.html?iso3=125&mapcode=0C.T4&xx=-6.271020&yy=53.347424 http://www.mapcode.com/getcoords.html?iso3=125&mapcode=0C.T4...
- Alupis 12y ago
  So, they want to throw out the old coordinates system (which was absolute location regardless of any "context"), with a system that if you loose the context information, or misinterpret it, you can wind up in a very wrong location? I've written a fairly extensive GPS library for some embedded device projects in the past, and I can attest to the computer not caring about the long coordinate system, they are just floating points really.
deleted 12y ago
[deleted]
apoorvai 12y ago
I think you need to change your "context" country. If I look for 0C.T4 in Ireland, I see green (implying a bench). It looks like the mapcodes are country specific, and two countries can have the same mapcode.

jib 12y ago

Yep. Swedish post codes define mail delivery areas as well. You can effectively sort on partials and get high accuracy. For instance, the office I used to work in handled all of 421xx, 426xx and 436xx, as well as a few of the 430xx range. Sorting was done by bucket sort (literally) on the top 3 digits in a central distribution location (all 5 for those like 430xx that was handled out of several offices), then distribution to each mail office, then another bucket sort on the full five digits, followed by another bucket sort on (roughly) street address, followed by a final sort on route. This appears to lose all of that functionality.

6d0debc071 12y ago

From the Mapcode System Reference Document: http://www.mapcode.com/downloads.html http://www.mapcode.com/downloads.html 'Unfortunately, a large part of the world population has no address. In India alone, well over half a billion people live in houses that have no street name. Millions of man-hours are lost every day trying to locate or deliver goods to people and businesses based on business cards like this: ------------------------------------------------------ Amri Patel, consultant New Sun Technologies, District 14, Pune Tel. +23984982217 Three miles east along the airport road, take second left past the golden statue, in the fourth street left ask final directions at baker across from white house. Figure 1. Typical Indian Business Card ------------------------------------------------------ As we all know, even having an address is only an initial step in locating a position. Knowing someone lives on Queens’ Road 123 in Brunnock still requires you to find out where Brunnock is, and where the Queen’s Road is, and where number 123 is. The mapcode system was designed as a free, brand-less, international standard that allows any location on the surface of the Earth to be represented by a short, easy to recognize and remember “code”, usually consisting of between 4 and 7 letters and digits.' So, your point number 2 seems closest to what they're aiming for. Indeed, later in the document, they state: 'The longer a code gets, the more awkward it becomes to use, the more difficult to remember, the more easy to make mistakes in copying or using, the less benefit it offers over more elaborate descriptions. Many other benefits depend on mapcodes being short. If length was not a problem, we might as well put our longitude and latitude on business cards and address labels.' > Also, won't there be multiple mapcodes for a single spot and won't that require cross-association of the respective metadata? It seems like this corresponds to a coordinate system. You say what country you're in and then this gives you an aim point. I don't think you need to say 'it's in This, which is in This which...' :/

jofer 12y ago

> "Latitudes and longitudes are unambiguous..." This is a tangent, but actually, they're not. There have been (oil) wells fail because someone gave a lat/long without specifying the datum, and someone else assumed it was in a different datum. Without a datum defined, latitude/longitude (no matter how precise) only gets you to within ~1km of an actual location. The Earth is not a sphere (or even an ellipsoid). Therefore, we need models of the the absolute shape of "sea level" (i.e. an equipotential surface - varies due to density variations in the Earth) to go from a spherical coordinate system to an actual point on the Earth's surface. These are referred to as a datum. Because our knowledge of the absolute shape of the Earth has changed over time, there are many different datums (ranging from spheres to ellipsoids to detailed gridded surfaces). There are a large number of datums that are still in common use. WGS84 is the most common (and very accurate), but NAD83 and NAD27 are also very, very common, as well as many others. If someone gives you a lat/long in NAD27 (e.g. read off of a printed map) and you assume it's WGS84, you can wind up over a kilometer away from the original location. (NAD27 is reasonably accurate for the US, but is very inaccurate elsewhere on the planet. I regularly see it used for data everywhere, though.)

kghose 12y ago
Thanks for teaching me about datums: http://en.wikipedia.org/wiki/Datum_(geodesy) http://en.wikipedia.org/wiki/Datum_(geodesy)
jxf 12y ago
You're absolutely right, and I should have said that! I was trying to contrast to the case of just typing it into some kind of map service, i.e. MapCodes. A lat/long pair unambiguously resolves to a single point in that service.