How long does it take Mapquest employees to type up all the directions people need into their database?

Question

How long does it take Mapquest employees to type up all the directions people need into their database?

Answer 1

one secound.....as fast as it can print..

Answer 2

Umm, they don't.  Can you imagine how long it would take for a person to type in every possible combination of driving directions?  It's not even feasible that people could do that.

How MapQuest Works

Introduction to How MapQuest Works

MapQuest.com generates maps and directions on the fly. In the Web site's first month of existence, it got a million hits, and its instant success spawned an industry. Online mapping applications are now a dime a dozen, but MapQuest is still the top performer.

How does MapQuest.com determine the "ideal" route? What are the most common errors and why do they happen? In this article, we'll look behind the scenes of MapQuest.com to find out how it delivers maps and directions, and we'll check out some of its lesser-known applications.

MapQuest is pretty much your quintessential online mapping program. Its main functions are FindIt, which lets you find businesses in a particular area; Maps, which creates a location map based on address, city, zip code or longitude/latitude coordinates; and Driving Directions, which generates a route from Point A to Point B based on as much address information as you can provide. It'll get you from house to house, city to city or from a mall in Vancouver to an airport in Florida, and it'll estimate how long it'll take you to get there.

Every day, MapQuest.com generates about 5 million maps and about 7 million sets of driving directions. MapQuest deals with a lot of data -- it covers the United States, Canada, France, the United Kingdom, Germany, Italy, Austria, Belgium, Denmark, Luxembourg, the Netherlands, Sweden, Switzerland and Spain to the street level, and it covers the rest of the mapped world to the city level. Sources for this coverage include MapQuest's own cartography data developed for its print publications, information from digital mapping companies like NavTech and TeleAtlas, and government databases like the one compiled by the U.S. Postal Service. MapQuest updates its information every three months with any new or corrected data that comes in from its sources.

MapQuest Technology

MapQuest as most of us know it is 34 servers housed in the AOL Data Center in Virginia. These 34 servers handle all of the data and number-crunching needed to create maps and driving directions on the fly. The task breakdown looks like this:

    * 15 servers generate maps

    * 15 servers handle geocoding (matching addresses to longitude/latitude coordinates)

    * 4 servers create driving routes

Each server is a self-contained unit that stores the same information as the other servers in its task group. If you ask MapQuest to generate driving directions, you'll end up using any one of 15 geocoding servers (we'll talk about geocoding in the next section), any one of 15 mapping servers and any one of four routing servers by the time the directions show up on your screen.

MapQuest's routing algorithm looks at all possible routes between two points and then picks one by weighing certain factors at each stage along the trip. The goal is to achieve the fastest, most direct route. It factors in characteristics such as what kind of road is involved (if it's between freeway or dirt, for example, it'll pick the freeway), how many turns are involved, how fast you can travel on the road and the number of intersections you'll encounter. Once it has chosen the ideal segment for each step of the way, it delivers a set of directions.

MapQuest inputs all of this data into its own technology infrastructure to turn it into the maps and directions displayed on MapQuest.com. Let's find out what that involves.

When the MapQuest routing servers generate a route, it also generates an estimated driving time. This driving time is based on travel speeds (typically posted speed limits) along each road segment and the amount of time it takes to navigate each intersection. According to Jim Greiner, MapQuest's Director of Marketing, intersection time is calculated "based on type of turn (left, right, crossing) and the number, type, and geometry of roads at the intersection." For example, the software assumes it takes more time to turn left from a minor road onto a major road than it takes to turn right from a major road onto a minor road.

In order to pinpoint a location on a map or provide driving direction from one point to another, MapQuest must first convert a street address into a latitude/longitude coordinate. This process is called geocoding.

A Little History

MapQuest has been around since the 1960s -- it started out making maps sold in gas stations. Back then, it wasn't "MapQuest." First, it was the cartography division of R.R. Donnelley & Sons, and then it set out on its own as the GeoSystems Global Corporation (GGC). GGC launched the MapQuest.com Web site in 1996, and it received 1 million hits in its first 30 days. GGC changed its name to MapQuest and went public in 1999. A year later, AOL bought the company.

Geocoding

Geocoding assigns a latitude/longitude pair to a street address. The result is not exact -- geocoding creates the best possible estimate based on available information. MapQuest uses one of several methods to arrive at a geocode.

Address Interpolation

This method provides the most accurate results. In address interpolation, streets are broken up into segments, and each segment has a range of addresses associated with it. MapQuest's software makes an educated guess at the location of a given address based on where it should be located within that segment. For example, let's say ask MapQuest to show you the location of "25 Elm Street, Hollywood, CA." A geocoding server will ask a mapping server for the best available data for Elm Street in Hollywood. It will then locate the segment with addresses ranging from, say, 1 to 49 on one side and 2 through 50 on the other. It will assume that 25 is at the center of the segment on the odd-numbered side of the street, and it will locate the address at the latitude/longitude coordinates for that position.

If it can't geocode an address using interpolation -- typically because the street isn't in its database yet or there are a number of streets with the same name in a given area -- the server will attempt to use either intersection matching (if the address is outside of the United States) or zip code centroids (if the address is in the U.S.).

Intersection Matching

To geocode an address using intersection matching, MapQuest finds two street segments: one segment near where MapQuest thinks the address should be located, and one that touches that segment. It then geocodes that intersection, which it assumes to be the closest intersection to the given address. In this case, MapQuest delivers a map pinpointing the intersection or directions to the intersection.

Zip Code Centroids

In the United States, every address has a "zip code" that corresponds to a particular region within a city. A zip code centroid is an area that corresponds to a five-digit, seven-digit or nine-digit zip code. Most of us are familiar with the five-digit zip codes, but those zip codes are actually broken up into smaller, zip+2 areas and even smaller zip+4 areas. The zip+4 centroid is the nine-digit zip code you sometimes see on official documents, and it typically includes only about 10 homes (you can look up the zip+4 code for your address using the USPS ZIP Code Lookup). If MapQuest can figure out which +4 centroid the address should be in, it will calculate a latitude/longitude pair that is at the center of that centroid. The next step is to try to place the address in a +2 centroid, and finally in the basic five-digit zip code area, which is quite large. These latter options don't return very accurate results.

Now that we know how MapQuest generates maps and directions, let's find out how we can use MapQuest.com to get the information we want.