Q's about Mapquest.

How does mapquest do what they do. Does toe DOT or somebody have routes and MQ just add this into their database?
Also, who owns it. I had a friend in 1990 that was doing something similar to what they do, and I thought he was an idiot!

Well, let’s see…
“How does Mapquest do what they do QUESTION MARK! Does **the ** DOT…”

The data comes from many sources. DOT may be one of them.

This is called GIS data. Geographic information systems. Many, many local and County governments have their own data sets. Road Centerline data is just one of many different layers. Some sell this data to places like mapquest, some don’t.

Google Tiger Data. The Census Bureau is heavily involved with GIS as well.

MapQuest was originally a division of R.R. Donnelley & Sons that was founded to produce printed maps, so they initially used the typical resources of such a company (some combinations of legal maps from government surveys and on-the-road tracking). In order to produce their maps, they began to get into electronic plotting of their data and began collecting a huge database of road information.
Some time in the 1980s, they began looking for ways to make money from the database (beyond just printing) and began to market software to use their data om Macs (probably in conjunction with some academic services–a market they were already serving in print). In the mid 1990s, Donnelly spun them off as GeoSystems Global Corporation with an eye to capturing the burgeoning home and office computer business. They then changed their name to MapQuest and were soon swallowed up by AOL.

I was at a trucking firm in the mid-1980s that was doing something similar. They were sending people out on the road with odometers tied to their computers and physically driving the roads, entering the locations of gas stations, toll booths, speed limit changes, retail outfits, etc. They then dug up who owned each of the gas stations so that they could poll them each day for fuel costs and added similar information for other places serving trucking needs. Even in 1986, a driver could get a trip-tik that would tell him or her the directions from a dock to a destination with speeds, detours, and fuel prices. It was proprietary to that company, so I do not know whether it was merged into or superseded by outfits like NAVTEQ.

Given their long history in the business, MapQuest probably has an enormous amount of base data on which to build. On the other hand, if you watch their windows as they display maps, you will see repeated copyright references to NAVTEQ. NAVTEQ is a company that physically sends out people to measure actual roads, noting distances, signage, speed limits, etc. (Whether they do it all themselves or subcontract out the work to local outfits, I have no idea.) So I would not be surprised to discover that MapQuest has moved away from doing any on-the-ground data collection, themselves, and have begun to buy their information.

As enipla noted, GIS is a really big industry, right now. It is employed by increasing numbers of government agencies to produce electronic maps of water, sewer, electric, and other utilities that can be easily overlaid onto property and highway drawings. Since the collection of that information is expensive, it is pretty much in everyone’s interest for the data to be sold to recoup the expense, so there is a LOT of shared (purchased) information being exchanged among a large number of government and corporate entities.

(Given the way that several of the mapping software outfits (MapQuest, Google, Yahoo!), tend to misplace house numbers for from a few yards to a few hundred yards, I am not sure that MapQuest is actually tied into an actual GIS network showing property lines and it is pretty clear that NAVTEQ is not recording house numbers as they drive by.)

Now that you have the info from tomndebb’s great post, are you just interested just in how they build the mapping database, or also how they generate routes? I don’t have the inside info but might be able to add something.

I have a GPS device in the car and it’s interesting to compare routes it generates to those on MapQuest, Google Maps, and Yahoo. They’re almost always the same. The GPS device is set up for speed priority (vs. distance priority). It has information in the database regarding speed limits on nearly all the roads, and uses that to figure out if you’re better off doing 62 MPH (it assumes you exceed the speed limit :slight_smile: ) on a highway for 10 miles or take a shorter route at 45 MPH.

I do not know the specifics of how they do it but it’s a very interesting problem from a software and algorithm standpoint. The most interesting part (to me) would be how to determine what routes to disregard. Obviously it can’t calculate every possible route then compare distances and times. So it must rough out the most likely routes first. And the online services are pretty fast.

Now that you have the info from tomndebb’s great post, are you just interested just in how they build the mapping database, or also how they generate routes?


Uhhhh…I dunno. It mystifies me how they can get directions from my house to the main road 1/3 of a mile away. This sort of thing is remarkable to me.

Thanks for great answers,

If they give your distance as 1/3 mile and you are, indeed, 1/3 mile from the main road, you got lucky.

As noted, they are frequently off by varying distances–in the case of my house, they show my house about 500 feet farther away from the main road than it actually is. (Their error in distance matches their error on the little flag they put at my location, so they are consistent on that point.)

Basically, they have collected and digitized information on all the roads that they can. (Think huge database). Then they do something to approximate where various addresses will occur on those roads. After that, it is simply a matter of telling the computer to track the distance across known roads for predetermined distances. (Obviously, THAT is a major accomplishment, although after at least 30 years of software development, there are probably several known routines and algorithms that they can use for the calculations.)

ESRI is probably the largest producer of GIS software. Here is theirNetWork Analyst. Refering to a network of roads.

We may start using it where I work to route emergency vehicles and such.