Your ability to get free maps will be almost 100% defined by the mapping program you choose.

Choose a program that supports many map and database formats and you will have lots of sources for free maps. 

If you are new to mapping, read the Mapping Basics page first.

Summary of the Mapping Basics page:

• All mapping products have essentially two elements: the digital map database itself and the mapping software that reads the map database and creates an image on the screen.  
• Good maps are more than just lines and shapes in an image: they include a database of important information associated with the features shown on the map.
• Some consumer mapping products can use only one map database, the one that's built into them.  If you want a choice of free maps, avoid such products.
• Some mapping viewers sold by old-style mapping companies will display only map databases in that company's proprietary format.  This is a trap for suckers.
• Essentially all mapping data comes from governments, and in the US such data is in the public domain.  Just about all the high-priced private map products originate in free, public domain government data that you too could use if only you could read the government's formats.
• Some commercial maps include genuine improvements and additions.  A large number are simply format conversions from free government formats into proprietary formats where the product can be sold for a very high price to the uninitiated.

The best way to get free maps is to use a product like Manifold System that includes support for numerous government formats.   This page assumes you are using Manifold System.  At $145, Manifold is such a good deal and it supports so many formats, that quite a few users of multi-thousand dollar GIS packages have purchased Manifold just so they can easily grab free data from the Internet and then convert it into their own formats.

Map Data comes from the Government

Virtually all map data originates with governments.  Just about all of the wonderful maps popping up on web sites or embedded within consumer applications utilize digital map data that governments created at the cost of billions of dollars.   Governments need to create detailed digital maps to fulfill their civil and military responsibilities and only governments can afford the remote sensing tools, such as satellites, as well as the capital and labor costs involved in creating detailed digital maps.

In the United States, like all other non-classified government technical material, all of this wonderful map data is free for the taking.  By law, it is in the public domain and can be taken and resold.  In fact, quite a few companies are in the business of taking free government maps, changing them a bit using tools like Manifold System, and then reselling those maps to the masses in the form of proprietary map products.

In contrast, virtually all other countries sell their government map data and attempt to enforce a government monopoly on the sale of map data.  Except for international map data created by the US, it is very difficult to find free maps of international areas.  To this day, the very best digital maps of the entire world are those created by US military organizations and released by the US government.

Remember: no matter how fancy the marketing of a specific digital map product, it is quite likely that most of the map originated in free public domain digital maps published by the US Government.  Although some companies do in fact provide significant additions or changes to government maps, most commercial maps that are based on government maps have few or unessential changes.  Despite the numerous marketing claims often made for privatized versions of government maps, most of the government data resold in proprietary formats has not been changed except to be converted from the government's open format to a proprietary map format.

For example, the Defense Mapping Agency's Digital Chart of the World is available for free download.  It's the best public domain international data set around.  Quite a few companies have sold this exact same data set converted to a proprietary format for thousands of dollars.  Good business if you can get it! 

Government Map Data

The government mapping environment is aimed at sophisticated users doing sophisticated things.  Maps are almost always vector maps, because those are the most accurate reflection of the data collection used to produce the maps.  Government maps tend to be highly specific and to focus on transferring key information.  They are shipped in data-oriented formats, and not in formats that are "prettified."  Users are expected to prettify the maps in whatever GIS package they use.

For example, a detailed government map of roads will be loaded into any GIS system using whatever default formatting that GIS system uses for lines.  To change the representation of roads so that principal highways use fatter or differently-colored lines is something you will do in the GIS system.  In Manifold, this is easy to do.

Government maps are often separated into different layers or different data sets because the information on a particular topic is far too much to include into one map.   For example, the Census Bureau's Counties 1996 dataset on US counties includes many hundreds of demographic variables for over 3,000 US counties.   Users are expected to pick and choose which variables they want from this data set and to then merge those variables into a map of US counties.  Manifold makes this easy (in fact, we provide the base maps and county data set on the Manifold CD itself).

Some government maps, such as TIGER/Line, are so detailed and so huge that part of the art of using them is to extract only that information (such as roads, boundaries, ZIP code information, etc) that is actually needed.  A sophisticated GIS package like Manifold makes it really easy to extract whatever information is needed and to save it as a custom map.  This is covered in detail in a step-by-step Case Study on the Manifold CD and available in this web site.

Internet Sources for Map Data

The number one source for mapping databases is the Internet.  A good search engine (we use Alta Vista, because it indexes every page on the web) is indispensable.   We don't use human-filtered search engines such as Yahoo! because such portals are really advertising sites that will adjust the content they provide to you based on who is paying them money.  Since there is no money behind free map data, there is no way for a free government site to outbid people who want to sell you their conversions of the free government data.  Learn to use a "neutral" search engine like Alta Vista.

Almost all mapping data begins with the Feds, but federal agencies seem to be divided into two camps: those like USGS and BTS that do a good job of providing data on line, and those like the Census Bureau who illegally try to restrict public access to what is supposed to be free data. 

Cool Agencies

See the Where to Get Maps topic in the 5.50 user manual for tips on getting thousands of maps for free from government web sites.  By far the best is the US Geological Survey.  They run a superb on-line environment beginning at www.usgs.gov that provides an enormous collection of maps.

Manifold® System can draw spectacular maps from freely available data. The image at left is a detail of a 1:24,000-scale SDTS hypsography file from USGS showing a  mountain reservoir.  Certain equal topographic lines have been selected in red.  Manifold provides sophisticated analysis in addition to map drawing.

Note that USGS provides online access to a lot of data in addition to map data.  Manifold System can read maps in USGS DLG, SDTS, or DEM formats.  Virtually all of the mapping that's done in the US is moving to USGS SDTS formats.  Manifold can also handle the military's VPF format.

The Bureau of Transportation Statistics at www.bts.gov provides much data on line or by shipment of free CDs.  BTS is a better source for database statistics than raw GIS data because they use a format that is nonstandard even within the government.  manifold.net has converted the key BTS basemaps into Manifold format and makes them available for free on the Manifold CD and on our FTP sites.  However, BTS publishes a lot of data in database formats that (of course) Manifold can read and which are highly useful in transportation studies.

Manifold FTP Sites

Manifold provides a treasure trove, over 30,000 megabytes, of free map data that we've downloaded or otherwise acquired.  Manifold is the only GIS company to provide the Digital Chart of the World for free, and we were the first to provide TIGER/Line 1995 for free.

Although it is not free, many Manifold customers like to purchase copies of free, or nearly free, data on CD for the convenience of not having to download several CDs in data.  manifold.net sells TIGER/Line 1997 to Manifold customers at $52 for a set of six CDs when ordered with Manifold.  The Manifold World collection is priced at $45 per volume.  This is slightly higher than the nominal $30 per CD charged by USGS for most CDs; however, Manifold World represents thousands of hours of personnel and labor time to restructure military maps into civil form.

Manifold also provides duplicates of numerous CIESIN data sets.  CIESIN creates cool data sets that are extractions from expensive Census Bureau data tapes.  These are very handy for advanced demographic analysis.

Links Sites

Manifold can read so many different formats that a great source of free maps is to visit one of the links sites that pop up in GIS.  Many sites will provide data in AutoCAD .dxf, MapInfo MID/MIF or ESRI shapefiles.  Manifold can read data in all of those formats.