Where to Get Maps

Manifold reads so many different formats it is usually easy to find many sources for maps and their components: drawings, images, surfaces and geocoded tables or other data sets that may be merged into tables. In this topic we refer to data that may be imported as any Manifold component using the generic term "GIS data."

Manifold users working with the United States have a seeming infinity of free data sources to work with. Federal law in the United States places essentially all GIS data sets created by the Federal government into the public domain. Since Federal agencies in the US are the most prolific creators of GIS data in the world, US users are blessed with an abundance of data, usually free of charge. The usual problem in the US is choosing which one of many possible drawings or images is the right one to use.

The situation in the rest of the world is much worse. Except for the US, most governments do not place GIS data in the public domain. Most governments charge high prices for any GIS data. Some governments discourage or openly outlaw any competition to state cartographic monopolies. For these reasons, free GIS data for much of the world is difficult to obtain.

General Sources for GIS Data

Manifold can read numerous formats for drawings, images, surfaces and tables. Sources for such data include:

The Manifold CD	A "starter" collection of base maps, including Manifold's base World map is on the CD. See the various readme.txt files and the comments within the .map files on the CD. Note that some .map files on the CD contain numerous drawings. Fetch drawings from these .map files using File - Import - Component to import just the drawing you want into your project. The .map files on the Manifold CD were all saved using the Compress .map files to save space option in Tools - Options in order to place more files onto the CD. When opened for use the resulting projects may be considerably larger than might be expected from the size of the .map file on CD.
The Internet	The Internet provides more access to GIS data at zero cost than any other method. Become expert at using a good search engine and crawling the web for sources. When downloading from the web, be alert for any accompanying documentation that describes necessary projection information or other metadata. Acquire a fast Internet connection and a large hard disk as well.
Manifold Download Sites	Visit the manifold.net web sites for information on downloading GIS data directly from manifold.net servers.
Government Sites	Agencies like www.usgs.gov, www.nima.mil, and www.census.gov (USGS, NIMA and the Census Bureau) on the federal level and various state and local agencies are placing more and more GIS data on the web for free download. Use government sites to get highly detailed drawings and maps for the area of interest.
Non-Profit Organizations	Non-profit organizations such as www.ciesin.org often provide sites with GIS data that originated in government but which have not yet been made available by government on the web.
Universities	Numerous universities operate web sites with free GIS data.
GIS Vendor Sites	Many GIS vendors operate sites that provide highly detailed GIS data in the format of their GIS systems. ESRI, for example, provides free downloads of highly detailed international data in .shp format from their www.esri.com site. Manifold can read such formats. Read the vendor's terms and conditions to see if your intended use of the data is permitted. Many vendors allow remarkably free usage of the free data provided on their sites so long as you credit them as the source of your data in publications.
Other Sites	"Ezines" focussing on GIS as well as sites run by individual businesses or GIS enthusiasts provide hundreds of gigabytes of GIS data for free. Use a good search engine or ask about in newsgroups to find these.
Peer to Peer Exchange	Internet newsgroups like comp.infosystems.gis or GIS lists are a good place to meet other GIS users for exchange of GIS data.
Libraries	Don't overlook public libraries as a source of GIS data. These are usually best for locating paper maps or printed photographs for scanning, a less preferred route to GIS data than direct electronic download via the web. Larger libraries will often have CDs on hand from the Census Bureau or other agencies. Bring a laptop into the library and copy the data onto your hard disk for later use. If it's public data, it's your right to copy it.
Government Libraries	Many government agencies have libraries that are open to the public. USGS has major libraries in Virginia, Colorado and Northern California that provide access to hundreds of CDs of USGS-published GIS data. Bring your laptop.
Federal Depository Libraries	By Federal Law, agencies are required to provide copies of their publications, including electronic publications like GIS data CDs, to Federal Depository Libraries. University libraries will often function as a Federal Depository Library for their particular location. If a library participates in the Federal Depository system, you must be granted free access to that library and allowed to use the Federal materials on file. Again, bring your laptop. Search the web for information on the nearest Federal Depository library to you.
University Libraries	University libraries are often open to the public for free or for a nominal fee. Any good university library will have a wealth of GIS data on CD available for use. Most have no problem with use of personal laptops or copying of GIS data that is in the public domain.
Government Sales	USGS provides numerous GIS data titles on CD for low costs. The Bureau of Transportation Statistics (BTS) will ship CDs to you for free. Numerous other agencies will sell data. Most government data in the US is sold for reasonable prices, but a few agencies charge illegally high prices. If confronted with a demand to pay $1500 for a couple of CDs, file a Freedom of Information Act request instead. Agencies cannot charge more than the cost of duplicating the data.
GIS Data Vendors	For those parts of the world not covered by publicly available NIMA data sets, the only options may be to create your own data or purchase it from a commercial vendor. In the US, the only sources of very timely and high accuracy data are commercial vendors. Vendors like TeleAtlas (www.teleatlas.com) provide good coverage of Europe. Manifold can read all common commercial formats.
Satellite Photography Vendors	Commercial satellite photography vendors such as IKONOS (www.spaceimaging.com) and SPOT (www.spot.com) sell satellite images from their huge inventory of existing images. Some companies will even snap a custom picture for you from orbit of the location you desire. Other sources include archives of Landsat and other data.
Freedom of Information Act	The United States guarantees access to virtually all unclassified Federal data via the Freedom of Information Act (FOIA). If you see a map created by any Federal agency, you should be able to get the GIS data that was used to create the map with a simple FOIA request. Use a good web search engine to find resources and step-by-step instructions for using FOIA. Before filing a FOIA request, please check carefully to make sure the data you seek has not already been published

Key Internet GIS Data Sources

Internet URLs change frequently. The URLs below were active when this documentation was created. If the URLs are changed, usually drilling down from the main web site for the agency or organization will find the current URL. In addition to USGS Geodata, the National Atlas, the Census Bureau and NIMA, there are many, many other resources on the web. For example, many state governments operate web sites from which GIS data may be downloaded.

USGS Geodata Downloads	www.usgs.gov is the first stop in the US for GIS data products. Numerous USGS servers provide many different sites from which data may be downloaded. http://edc.usgs.gov/doc/edchome/ndcdb/ndcdb.html - A Manifold favorite for USGS data. See this site for documentation and detailed information on the various data sets provided. This site provides free downloads for: 2M DLG - 1:2,000,000-scale drawings showing boundaries, major roads, hydrography, etc. for the United States. Suitable for background maps and overviews at the state level. 100K DLG - 1:100,000-scale drawings showing features in greater detail. Used by many for roads and similar features at the county or city level. 24K DLG - Actually published using SDTS format, these are the vector drawing equivalent of USGS paper topological "Quad" maps. Very highly detailed roads, hydrography and much more. Used for local work. 250K DEM - 1:250,000-scale Digital Elevation Modules (terrain elevation) suitable for use as surfaces at the county level. 24K DEM - 1:24,000-scale Digital Elevation Modules published in SDTS format suitable for use as surfaces at the local level. Equivalent to "Quad" maps. Extraordinarily detailed. Use the SDTS drawing importer to import these (a surface will automatically be created even though a drawing importer was used). Note: USGS is now moving free downloads of SDTS DEMs to third parties. LULC - In 1:250,000-scale and 1:100,000-scale versions. Land use and land cover data provides information on urban or built up land, agricultural land, rangeland, forest land, water, wetlands, barren land, tundra, and perennial snow or ice. Associated data sets display information in five data categories: (1) political units, (2) hydrologic units, (3) census county subdivisions, (4) Federal land ownership, and (5) State land ownership. The1:250,000-scale resolution maps yield spectacular maps when thematically formatted in Manifold. NCLD - A collection of raster data sets, one per state, that provides extensive land use data for the US as rasterized data sets. Derived from the early to mid-1990s Landsat Thematic Mapper satellite data, the National Land Cover Data (NLCD) is a 21-class land cover classification scheme applied consistently over the United States. The spatial resolution of the data is 30 meters and mapped in the Albers Conic Equal Area projection, NAD 83. These are imported into Manifold as surfaces using the Raw Binary Files importer. See the Import a Raw Binary File - NLCD topic for an example.
National Atlas of the United States	http://www.nationalatlas.gov/atlasftp.html - The National Atlas of the United States Map Layers Warehouse. Download dozens of data sets for free in either shapefile or SDTS format. SDTS results in more complex projects (because SDTS contains more information, like metadata comments) but it guarantees correct projection information import. Everything from Abandoned Mine Inventory, Agriculture Census, Airports and Average Precipitation to Volcanoes, Water Features, West Nile Virus 2000 and Wildlife Mortality. Includes many database tables in DBF format as well.
US Bureau of the Census	http://www.census.gov - The Census Bureau has begun placing data on line for download. Drill down to subsequent pages, like http://tiger.census.gov/ to find specific data sets. There are many pages that just serve images: drill deeper to find the actual GIS data sets for free download. A favorite Manifold site is http://www.census.gov/geo/www/cob/ the home page for Cartographic Boundary Files. TIGER/Line - A highly detailed, complex GIS data set providing streets with address ranges, boundaries and numerous other detailed features for the entire US. The basis for most commercial street maps. See the Census Bureau's Tiger pages. Boundary Files - States, Counties, Congressional Districts, Metropolitan Areas, Urbanized Areas, Incorporated Places, County Subdivisions, School Districts, Voting Districts, Census Tracts, Census Block Groups and much more. Usually organized by State. Download in .e00 format so that they will import by default into Manifold with the correct NAD83 datum used by most files. Alternately, when importing .shp versions (preferred by many people because the result of importing .shp files are simpler, better organized projects) use Edit - Projection - Current Projection to change the datum to North American 1983 (mean for Conus). ZCTAs - ZIP Code Tabulation Areas are the Census Bureau's representation of ZIP codes as areas. We predict these will become a standard for demographic work. Gazetteer - Places, ZIP and other centroids.
National Imagery and Mapping Agency	http://www.nima.mil - The primary source for public domain international data. Download the most detailed international data available in the world. Drill down to find maps and geographic data at the NIMA Geospatial Engine (currently at http://geoengine.nima.mil). VMAP1 - VMAP Level 1 data: the world on 232 CDs at exquisite detail (1:250,000 to 1:100,000-scale). NIMA has released some data, but not all. File a Freedom of Information Act request for what you need if they do not have it available for download. VMAP0 - VMAP Level 0 data. Updated edition of the famous Digital Chart of the World. DTED - DTED Level 0, terrain elevation data for the world. DOI - Georeferenced SPOT satellite imagery for much of the world. JOGA - Joint Operations Graphic - Air, JOG-A (1:250,000 scale) digital raster graphics images. (scanned paper charts). ONC - Operational Navigation Chart, ONC (1:1,000,000 scale) digital raster graphics images. (scanned paper charts). TPC- Tactical Pilotage Chart, TPC (1:500,000 scale) digital raster graphics images. (scanned paper charts).
Bureau of Transportation Statistics	http://www.bts.gov - A "must have" CD for every serious GIS person is the National Transportation Atlas Database (NTAD). In addition to key transportation layers it has many general purpose GIS data sets as well. At the current writing, BTS will ship you an NTAD CD free. It may be "ordered" at zero cost from the BTS web site. Several of the data sets on the Manifold CD come from the NTAD.
CIESIN	http://www.ciesin.org - The Center for International Earth Science Information Network at Columbia University: see their Data Resources page for links to the archive of Census related products (detailed demographic data), fundamental GIS layers for China, world population data and more.

International GIS Data Sources

National Imagery and Mapping Agency	http://www.nima.mil - The primary source for public domain international data. See notes in the table above.
Bureau of Transportation Statistics	http://www.bts.gov - Provides transportation GIS layers for Canada and Mexico as part of its North American Atlas Database (NORTAD) free CD.
Geogratis	http://geogratis.cgdi.gc.ca - Cool Canadian data from Natural Resources Canada for free download, plus links to other free data sites. Includes the National Atlas of Canada.
NOAA GLOBE	The Global Land One-km Base Elevation (GLOBE) project provides the latest, most modern, public domain terrain elevation database for the entire world. Currently at http://www.ngdc.noaa.gov/seg/topo/globeget.shtml, the data set may be downloaded in 16 "tiles," most of which are very large files (over 100MB each) when unzipped. Import using the DEM *GLOBE Files (.)* setting in File - Import - Surface.
CIESIN	http://www.ciesin.org - The Center for International Earth Science Information Network provides GIS layers for China and world population data.
TeleAtlas	http://www.teleatlas.com - Not a free download site, but a commercial vendor of very high quality, very detailed Western European GIS data. Their Etak subsidiary in the US at http://www.etak.com provides detailed US streets data.
Other resources	If you can find it online in one of the common GIS interchange formats (.shp, .mid/.mif, .e00) it's almost certain you can read it in Manifold. Many vendors provide GIS data for free without restrictions.

Commercial Sources

Although the emphasis on the above is on free data sources, there are many fine companies providing GIS data for a fee. Such companies often begin with government data for a particular region and then enhance it by reorganizing the data into more user-friendly form, correcting mistakes, updating the data and so on.

Creating Your Own Data

Always keep in mind the possibility of creating your own data sets. This may be required for some international users if commercial or government data is not available. There are several methods to create a custom map:

Acquire GPS data points	Manifold includes a connection to GPS devices controlled by the GPS Console . For small regions such as ranches and farms it's remarkably easy to create a map by driving or walking boundaries with a GPS device connected to a laptop running Manifold. GPS data points can be used to mark control points used to georegister aerial photographs.
Scan a paper map	Although almost all modern maps are created digitally, many maps still exist in paper form. This is especially true of historical maps. One can scan a paper map as an image and then georegister it using control points that appear in digital maps that map be obtained. Scanned maps can be used as images (slow and inefficient) or converted into drawings using tracing .
Scan a printed photograph	Printed photographs may be scanned and georegistered like scanned paper maps. Many libraries have archives of aerial photographs that can be scanned. Modern flatbed scanners are very light and are easy to carry into a library together with a notebook computer for scanning of materials that are not allowed to circulate outside the library.
Custom aerial photography	Custom aerial photography ranges from inexpensive to very expensive custom work. Most GIS purposes can be accomplished with inexpensive, ad hoc aerial photography. Visit a local airport near the area of interest and hire a pilot and a Cessna for an hour. Shoot a roll of film (or use a quality digital camera) from a suitable altitude on a clear day and many images will be very useful once scanned. Georegister them using control points. Tip: Crack open the door a bit and shoot down through the crack so no glass is between the camera and the scene. Search the web for other aerial photography tips.
Custom satellite photography	Stock satellite photographs with two-meter resolution will frequently sell for under $100. Custom satellite photography from commercial operators is occasionally available for under $500 an image if the satellite viewing swath traverses the target area. Prices will no doubt come down as the amount of stock photography and satellite competition increases.

Tables as Sources of GIS Data

Much data is published as tables in various forms that can be used in GIS work even though the tables are not geocoded. A good example is the Counties series of data sets published by the Census Bureau on CDs with titles like Counties 1999 or the City and County Databook. Such data sets are collections of tables, often in .dbf dBase II format.

A typical table might consist of records of demographic data for each county where each record has the county FIPS (Federal Information Processing Standard) numeric code identifying the county together with other data fields. We can use such tables in Manifold if we first import a drawing that shows counties that also has a FIPS code field for each county. We can then form a relation between the drawing's table and whatever table was imported from the demographic data set. This same technique can be applied to use tabular data in many different types of GIS work.

Tables may also appear in electronic documents using non-database formats. For example, one might encounter a PDF file containing a table, an HTML web site page showing a table or a Microsoft Word .doc file that contains a table. The experienced user will learn Windows techniques for transforming such data into a format that can be read as a table by Manifold.

For example, we might highlight some tabular text in a PDF file, paste it into a Microsoft Word document and the use Word to convert the text into a real table. We could then "clean it up" if need be in Word and save it either as an HTML document containing a single table or write it out as a .csv ("Comma Separated Values") text file. Sometimes clever use of search and replace to convert tabs to commas or other character manipulations within Word will help us create the table we desire for import into Manifold.

Notes

Respect copyright laws: It is important to become familiar with the copyright laws that apply in your jurisdiction. Knowing the law will help you avoid accidentally ripping someone off, and it will also prevent unscrupulous data providers from ripping you off as well.

Web sites change constantly. The URL's mentioned above or the availability of the data sets described may have changed since the publication of this document.

A Call to Arms

When living in a free society it is easy to become complacent about one's freedoms and rights. If you live in the United States you have a right to get and use public data, but that right will disappear if you are not vigilant about maintaining it. Even as Internet makes it easier and cheaper than ever for agencies to provide public access to public data, some agencies are using Internet to make it harder to get access to public data.

A recent trend, for example, is for many state and federal web sites to present only PDF files or web-served images of data instead of the real data themselves in some publicly accessible GIS format such as .shp. Whenever you run across a web site that provides access to only images of the data, take a moment to email the people affiliated with that web site to ask them how you can get access to the real data. Encourage them to post links that allow download of the actual data. If they refuse, ask them to whom in their agency a Freedom of Information Act (FOIA) request should be addressed to get the data. Most states have a statute equivalent to the FOIA that allows you to get access to public data whether the agency likes it or not.

Some agencies mean well: they know that GIS usually costs many thousands of dollars per license so they put effort into providing images in the belief that the public cannot afford to work with the real data. Bring them up to date: tell them that Manifold makes it possible to work with the most sophisticated data to as great a degree of sophistication as one chooses at prices no higher than ordinary Microsoft Office applications. The more sophisticated the data is, the more important it is that users be able to work with it as real data.

See the Essay Public Access to Public Data for a rant in support of public access to government data.

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