By Dale DePriest - All rights reserved.
This article is intended to cover the various digital map sources available in the USA. In a few cases these same map makers also build maps for other countries. These worldwide map makers include NavTech and TeleAtlas but that is not the focus of this article. This article will describe in a general way what a user might expect if their software product uses one of these map sources.
The source for the actual maps often rests in the individual county planning agencies. Since there are thousands of counties in the USA there is an obvious difficulty in obtaining up-to-date maps. Further the county agencies often depend on road plans submitted by developers and thus may have maps that include streets that are not built yet and perhaps never will be. One answer is to use aerial photographs but they don't tell you the name of the roads and some of the roads are obstructed by foliage. In addition the digital map makers often want information that is not part of the map graphics. A more technical name for these digital mapping products are Geocoding or GIS (Geographic Information System) since they include much more data than just visual maps. Often there is no choice but to just drive the roads themselves to get accurate data or to depend on other independent sources such as input from users.
The fact is: no digital maps are entirely accurate. A user needs to know which map makers are used by the product that they are interested in and check the maps for the area that they are concerned about. In addition some map databases are created from vector data while others are just scanned copies of paper maps. To understand the difference please read my article on Map Display Formats.
In addition to mapping data these same map makers can often provide poi (points of interest) data. However, a software company might use the maps from one company and the poi data from another. POI data normally takes three forms. One is public buildings, parks, airports, and possibly geographic objects. A second is government locations that inlcude specialized points lists like marker bouys, and airplane marker. Finally, there are commercial establishments, which usually includes some information about their product and contact data. Note that the location of commercial places is often derived from the street address and is not based on the actual lat/lon location. See below for more data on poi's.
The listing that follows is just the start of a mini review of each
map maker. I have tried to include links so that the user can view sample
maps and can submit updates and corrections for the maps they use.
This section includes the various map makers that create digital
maps for use on the road. Note that some road maps include rivers,
lakes, and shoreline data as well as railroad tracks. They may even
include outlines for parks and recreation areas. The fact that the map
maker includes this data does not mean that every program the maps
will use all of the data.
Tiger is the main US government source for road mapping data. This is free data and is available from their web site. Problems with the maps and data can be forwarded to the agency under Feedback, but don't expect an update very soon. They have a MapBrowser that can be used to view their maps.
Tiger maps were developed by the Census bureau from USGS (United States Geological Survey) data initially but since there were originally only for census use they were not developed with high accuracy. The roads locations were not accurately mapped in all cases and the turns and other features were simplified. For example curved sections are reprented with a few straight line segments making clover leafs look a little odd. Data is updated in regions and areas as the need arises and money becomes available. The last major update was done as a result of the 2000 census. The map browser however is based on the 1998 data.
POI data from Tiger maps usually only have public data. They also have specific gis data for specialized applications.
There is an effort to improve the Tiger data. Please read the article entitled Private Sector Makes Census Bureau TIGER Roar that appeared in Geospatial Solutions.
Products using Tiger Data augmented with their own research include
Delorme and ALK CoPilot.
NavTeq (formerly NavTech) is a major player in vehicle mapping products. They supply most of the maps used by all of the major automobile systems in the USA. Their web site can be reached at NavTech for the end user. They are very interested in Driver Feedback. For the entire USA using Navteq check Maporama.com. You can also view their maps online at MapsOnUs.com to determine how up date they are.
In 2001 these maps only covered major cities and connecting roads. While this was fine for cars traveling in the city they did not meet the needs of many users. NavTeq decided to achieve nationwide coverage by adopting map sources that were not up to their earlier standards and have had mixed results in street level accuracy in outlying areas. Many of these map sources were based on Tiger maps or old USGS maps. NavTeq is trying to update the data both in accuracy and completeness. They make quarterly updates to their database but very few of their customers update maps that often.
An interesting freeway feature of the Navteq database is that they store the exact name listed on the freeway sign for all of the exits. This can permit an exact match with the route specified in the program and the name you see on the sign. Not all programs take advantage of this feature.
Navteq is building its own poi database and claims to have about 1 million locations for the USA. For the fancy car systems they use a database from Dun and Bradstreet.
Click here for a review
of a product that uses this database.
A company called ETAK was formed to provide accurate mapping data for the USA. They were recently purchased by a major European mapping vendor called TeleAtlas. The TeleAtlas USA site provides information on their products for the USA. They are also interested in Driver Feedback. To check the accuracy for you area view the maps at the TeleAtlas site can be used to determine the completeness of this data for your area.
The TeleAtlas maps have had Nationwide coverage for a long time, but like NavTeq much of the countryside surrounding the major cities is based on Tiger data and USGS data. They are trying to get their database up to date as well. They have released a new map set that is based on corrections from aerial photographs that should improve the placement accuracy of their roads.
TeleAtlas uses infoUSA for its commerical poi database. They do correct the database themselves when they drive the roads to check an area.
The Pharos Ostia product, Navman, and TomTom Navigator uses TeleAtlas maps in the USA. Click here for a review of a product that uses this database.
TeleAtlas is in the process of merging their data and GDT data based
on their acquistion of this company.
GDT (Geographic Data Technology) was another mapping company that
produces digital data for mapping. The have been purchased by
Rand McNally is considered a map maker but for digital data they use Etak (TeleAtlas) on their StreetFinder product but interestingly they are listed as a NavTech customer. They also own Thomas Guides which is a map maker with their own source of digital mapping products. The Thomas maps are quite accurate and up to date but only available for parts of the USA.
Their POI data somes from infoUSA and from the Mobil Travel Guide.
It is extensive. It includes museums, grocery stores, shopping, auto
repair, government buildings, and many other items. Some of the
Restaurants even show the Mobil Travel Guide Ratings.
Delorme has flip-flopped a couple
of times on their road product. They were originally using Tiger maps
as a source and then correcting and updating these maps themselves
with an internal database made by research and corrections sent in by
users of their Street Atlas product. In version 8 and 9 they used GDT
maps unmodified, but recently they have switched back to the Tiger plus
their internal updates. Send them email
for information in how to supply database updates.
The Garmin Cartography department controls the maps that are used in Garmin products. Most of their products come from one of the map sources listed above. They have a map viewer that can be used to look at maps from several vendors and they also have a feedback form that can be used to submit map changes. To understand the relationship between Garmin mapping products and the mapping vendors above please refer to this chart.
|City Navigator North America||NavTech|
|City Select North America||NavTech|
|Metroguide USA 4.0 and below||TeleAtlas|
|Metroguide USA 5.0 and above||NavTech|
|US Roads and Recreation||Tiger|
Garmin gets its poi data from a number of sources and includes
5 million poi's in its newest City Navigator product. As of version
7 they seem to have adopted NavTeq poi data.
here for a review of a product that uses this database.
Magellan offers maps for their gps units. Their road maps seem to be based solely on Tiger Data except the new Map Send DirectRoute product which may be using NavTech. Here is a link to their Products. The vehicle products use NavTech maps.
Magellan claims 2 million poi's in their direct route product. New
updates seem to be using the NavTeq POI database.
Lowrance offers maps for
their gps units. Their older road maps seem to be based solely on Tiger
Data. Here is a link to their Products. Their
newer routing products use NavTech data.
UnderTow Software Inc
UnderTow software is the new owner of Chicago Maps which makes the precision mapping streets product. As of their 6.0 release they have licensed the GDT data and presumably now TeleAtlas. Older versions were based on Tiger data.
They can also create custom map databases for business use and would thus be a competitor for Maponics.
Microsoft has entered the map business as well. They use a combination of NavTech and GDT as their primary sources. NavTech is used to cover the cities while GDT covers the outlying areas. CoPilot
Copilot from ALK uses Tiger data
and then corrects it with customer feedback and satellite
imagery. Errors should be emailed to the company. They use NavTeq maps
for Europe. ALK also makes PC*Miler which is a product specifically
for trucking. One source for their POI data is Zenrin.
Zenrin makes the software used
in Nissan and Infiniti automobile systems as well as trucking systems
and Sanyo systems. They also make exit freeway data that is available
for sale separately (see below under POI). Their
system has detailed maps and data for cities but less detail for
surrounding areas. They seem to have started with Tiger data and then
supplemented it with driving the cities and freeways. Errors can be
reported using their
error reporting system.
Maponics is a variation on
the companies listed above it that they do not produce a consumer
product that you can just buy already built. Instead they produce
custom maps for companies. Their goal is to be a company's mapping
department. They use Tele-Atlas maps for their source database and
then customize the map to add specific customer needed data. They can
do such things as store locator maps, customer density maps, post
office carrier maps for targeted advertizing, and many other tasks.
The source of almost all topo mapping in the USA is the USGS (United States Geological Survey). These maps cover the entire USA and were originally produced by hand surveys. Today they are updated from aerial and satellite photographs. The original digital maps were called DRG's (Digital Raster Graphics) which were nothing more than scans of the paper maps. These are still a popular form since a map is a picture and contains some beauty as a map art form and provides some detail that is normally not available in other forms. In addition to these maps there are also DEM (Digital Elevation Models) databases that contain very accurate elevation profiles and DLG's (Digital Line Graphics) which are vector map databases. These three sources are the primary map databases used by most topo products in the USA. They are sometimes supplemented with Aerial Photos, Orthophotos, and other imaging data.
USGS data can be many years old but this is usually not a problem as terrain features do not change often. However, man made objects such as buildings and roads may not reflect current conditions.
Magellan topo maps are based on USGS 1 degree DEM (Digital Elevation Model) data. The display of these maps is done with vector data.
Garmin topo maps appear to be derived from the USGS DLG topo maps of 1:100,000 which use contour intervals of 10 meters or 20 meters. The display of these maps is done with vector data.
Delorme topo maps are from USGS DLG topo maps of 1:24,000. The display of these products is vector data except that they have one product that also includes DRG drawings as well.
Most other topo map vendors and some Delorme products use 24K and 100K DRG maps. A few map vendors, such as MapTech, scan the paper maps themselves to produce their own DRG files. They feel that they can get better resolution this way. In some cases these maps are augmented with high resolution DEM data particularly for the profile and 3D views.
Some products augment the DRG maps with other database items such as the DEM data. A DRG file is only a picture so if there is a search capability for objects, roads, etc. then there must be a second database containing this data.
Here are some comparisons of various topo maps from gpsinformation.net
Marine charts in the USA come from official government sources. The parent organization is NIMA (National Imagery and Mapping Agency). These are primarily the NOAA charts that are updated as needed by NTM's (notice to mariners). NOAA offers an Electronic Nautical Charts (ENC) database that provides vector data.
NOAA also provides a Raster Nautical Chart (RNC) database but some vendors simply scan the paper NOAA charts and provide these raster images as their database. These images may be supplemented with a database containing NavAids for use with their program.
A commercial source of this information includes Navionics. They also product a Fishing Hotspots product for inland lakes.
Garmin Blue Charts are a vector database derived from NOAA charts and updated with NTM's up to but not including the month that they are release.
Magellan and Lowrance uses the Navionics database.
Aviation data in electronic form generally is all obtained from a single source called the Jeppesen database. Note that Jeppesen is a worldwide database. This data is updated frequently and is generally purchased as a subscription with monthly updates. The data comes from government sources. The USA government organization for all mapping data is NIMA (National Imagery and Mapping Agency). This data includes government Digital Aeronautical Flight Information File (DAFIF) sources including NOTAM alerts and FLIP publications as well as some FAA data from NACO (National Aeronautical Charting Office).
Some applications use scanned aeronautical charts which may be
supplemented with NavAids from a database.
There are a number of sources for poi data available in the USA. These
are usually business listings and represent an electronic yellowpages
full of data. This usually includes contact data, location, basic
services, and name. Location is usually be street address so this must
be translated for gps use.
Interstate America is a company specializing in interstate exit
data. This is used on Garmin receivers to display the exit data. Another
freeway exit data company is Zenrin.
They include special amenities available at each business and service
such as 24 hr. service, large vehicle parking, diesel gas, ATM, car wash,
LP gas, etc.
InfoUSA is a major player in
the business yellowpages market. They include more that 14 million
sites across the USA with everything coded by SIC codes. Of course,
many of the items on their list would be of no interest the average
recreational GPS user. Their major direct competitors include Dun and Bradstreet, Acxiom, and Experian.
Other competitors who also include reviews and other data on their
poi lists include Mobil
Travel Guide, AAA, and Fodors. Usually you see these sold as
ratings for travel books that include hotels and restaurants, or
specialized books like RV guides.
Grass Roots effort
There are also some grass roots efforts to build maps for various gps devices. One of the most successful for Garmin is
CGPS Mapper. They have maps
for most of the USA and even a lot for the rest of the world. Quality
depends on who built the map. They will also tell you how to build your
There are a number of sources for poi data available in the USA. These are usually business listings and represent an electronic yellowpages full of data. This usually includes contact data, location, basic services, and name. Location is usually be street address so this must be translated for gps use.
Interstate America is a company specializing in interstate exit data. This is used on Garmin receivers to display the exit data. Another freeway exit data company is Zenrin. They include special amenities available at each business and service such as 24 hr. service, large vehicle parking, diesel gas, ATM, car wash, LP gas, etc.
InfoUSA is a major player in the business yellowpages market. They include more that 14 million sites across the USA with everything coded by SIC codes. Of course, many of the items on their list would be of no interest the average recreational GPS user. Their major direct competitors include Dun and Bradstreet, Acxiom, and Experian.
Other competitors who also include reviews and other data on their poi lists include Mobil Travel Guide, AAA, and Fodors. Usually you see these sold as ratings for travel books that include hotels and restaurants, or specialized books like RV guides.
2003/2/8 very preliminary version.
2003/2/15 some additions.
2003/2/19 added marine and aviation sections.
2003/5/1 added some more references and links to map reviews.
2003/5/12 added link to teleatlas map viewing site.
2003/5/12 added link to Garmin review, and Magellan DirectRoute.
2004/1/11 added poi section.
2005/2/3 revised GDT, Lowrance and added Zenrin.
2006/1/19 corrected mapsonus reference, added ALk and improved Zenrin.
2006/4/38 corrected mapquest reference.
2008/9/16 added grass roots choice.