NAC Meta Tag for Web Pages And Local Searches
Indexing web sites according to their locations is both challenging and critically important
for all search engines on the Internet. Currently most search engines are using location
information from other sources such as yellow pages and geocoding the street addresses with
street address geocode databases. There are no established standards yet. If you make a
local search on Google or Bing with keywords and street addresses, you may get many irrelevent
results, outdated results or wrong results while those you really want may not appear.
This is because these data sources are not under the control of the listed businesses which
know their up-to-date information but have no direct access to the data sources to update
Though it has been a common practice to harvest and update the data sources for keywords
searching directly from the world-wide web by robots of search engines, why are the data
sources for local searches not being harvested and updated by robots? There are many
difficulties prevent search engines from doing so. If they extract street addresses
from web pages, firstly, street addresses are not well standardized to be distinguished
from other texts; secondly many companies including street addresses on their web pages
just want to tell that they are real companies with physical addresses, but do not mean
that they are in service sectors like restaurants and hotels to receive customers in their
physical locations; thirdly many irrelevent street addresses may appear in articles of
a web page; fourthly, street addresses are language, culture and scripts dependent and
extremely difficult for search engines to correctly parse and geocode.
Now some search engines ask business owners to create and update their records themselves.
It seems that the results could be greatly improved. However, there are many search engines
on the Internet. How can a business keep updating changes on each search engine manually?
On the other hand, this is not a standard approach that have been accepted by all search
engines which keep introducing their own ways.
Therefore, a standard and search engine neutral approach should be introduced, that requires
least efforts from the listed businesses and also totally free to the listed business as
the information of the paid listings is biased and not valuable to endusers. These lead to
the introduction of a new location meta tag on location sensitive web pages. Then all search
engines just index each location sensitive business using the location meta tag found on its
web page, and exclude web pages without the location meta tag from the local search databases.
Now the question is how to define the location meta tag.
Though traditional addresses are still popular in the world, they are not digital and
need databases to geocode into lat/lon coordinates; they are language, script and culture
dependent and are extremely difficult for machines to read, understand and parse; they
are defined only at very limited locations of houses and buildings in urban areas and more
than 99% of locations in the world do not have street addresses; they are always long and
inefficient; they are not always unique and often duplicated at different locations; they
are not fine enough to specify individual entrances of buildings. Therefore, traditional
address are not condidates for the location meta tag.
You may consider using latitude/longitude coordinates to define the location for the location
meta tag. It's true that latitude/longitude can define every location in the world, but it
has problems too. It is geodetic datum dependent. One pair of latitude/longitude coordinates
in different datums can produce differences more than one kilometer. Latitude/longitude
coordinates are represented in many different formats: latitude preceding longitude, longitude
preceding latitude, North, South, East, West, degrees, minutes, seconds, decimal numbers, etc.
Latitude/longitude coordinates are also very long and longer beyond the capability of consumers
to remember. All these have made latitude/longitude coordinates not a good candidate to
represent the location in the location meta tag.
To solve these problems, NAC Geographic Products Inc. introduced a new meta tag called
NAC Meta Tag
for web sites of location sensitive businesses which receive customers in their physical locations.
NAC Meta Tag can be represented as
<meta name="NAC" content="XXXXX XXXXX" >
where "XXXXX XXXXX" is a Natural Area Code
(NAC) representing an area or a location depending on the length of the code. Natural Area Codes are
highly efficient language, culture and script independent digital codes to represent all areas and
locations in the world. They are designed for all people in the world to specify areas and locations
for all kinds of purposes as universal area codes, universal addresses, global postal codes, universal
map grids, geographic coordinates, universal property identifiers, etc. You can have up to 10 characters
for the NAC Meta Tag content such as
<meta name="NAC" content="8KDXF PGG5G">
(Panda Cafe in Washington D.C.).
<meta name="NAC" content="8KDB PGFD">
<meta name="NAC" content="8C Q8">
(City of Toronto)
More characters a NAC has, more specific area it represents. A ten-character NAC represents
roughly one square meter anywhere on the earth that can be used to specify the door of a building.
An eight-character NAC represents an area about 35 meters X 25 meters like a building.
A six character NAC represents a square kilometer like a neighborhood, and a four character NAC
represents a 30 km X 23 km area like a city.
Once a website has included a NAC Meta Tag, it means that it's a location sensitive business
or an attraction which welcomes visitors to its physical location defined by the NAC Meta Tag
content (i.e. its Natural Area Code). It has a higher accuracy than a street address embedded
in a web page and can be directly converted into latitude/longitude coordinates mathematically
without any databases. If a search engine stores the NAC Meta Tag content in its database as
a series separate NACs to represent all the levels of the NAC cells containing the NAC or store
the record into a hierarchical database organized according to the NAC levels, then the location
matching in local searches will be very efficient. For example, a web site with the NAC Meta Tag
<meta name="NAC" content="8KDXF PGG5G">
can be stored as five NACs: "8 P", "8K PG", "8KD PGG", "8KDX PGG5" and "8KDXF PGG5G" or in a
hierarchical database under "8 P"->"K G"->"D G"->"X 5"->"F G". When a user makes a local search
with "NAC: 8K PG", the search engine can simply pull out all records with NAC: 8K PG or all records
in the database under "8 P"->"K G" acoordingly.
That is, it turns the complicated location matching (converting the address into latitude/longitude
coordinates, calculating the distance to each of the possible businesses and then filtering away
those with distances larger than the specified radius) into a simple string match or a hierarchical
data retrieval which can dramatically reduce the search time.
If a web site does not have NAC Meta Tag, it means that the web site does not want to be
indexed for local searches and a search engine should exclude it from the local search
So, we have seen that NAC Meta Tag can make web sites correctly and accurately indexed in
all search engines, help search engines produce more relevant and accurate search results in less time
and allow endusers to use one standard highly efficient and language/scrippt independent code
- Natural Area Code to specify any area or any location in the world for local searches as
shown on http://nactag.info/local.asp.
With NAC Meta Tag embedded onto the web page, a business needs to update its information only on
its own web page that can be indexed and updated in all local search databases by the robots of
search engines automatically to guarantee their searching results up to date.
All end users including businesses do not need any licenses to use the NACs of their own addresses
on their own websites, business cards, letter heads, envelopes, advertisements, etc. You can obtain
your NAC or the NACs of other locations anywhere in the world on the high resolution satellite
image maps on http://nactag.info. To store, display
and handle a collection of NACs, you must contact NAC Geographic
Products Inc. to obtain a license.
NAC Meta Tag represents a new generation of technology for local searches on the world-wide web.
Copyright © 2002 - 2019, NAC Geographic Products Inc. All Rights Reserved.