Introduction

ThinkGeo's Map Suite product line and GPS tracking solution—Cygnus Track—both use map data sources for their mapping and tracking applications. The Map Suite products, such as Geocode USA, utilize TIGER® data from the U.S. Census Bureau to develop highly optimized datasets that enable users to find addresses anywhere within the United States. The map datasets for Cygnus Track can be fully customized to use a wide variety of map data sources. This custom map data integration feature allows Cygnus Track users to integrate high resolution satellite and street maps into the system to reflect any part of the world. Many of the types of map data used in ThinkGeo's mapping and asset tracking products, as well as the providers of these map data sources, will be discussed in this article.

In order to develop a better understanding of the applications of map data sources and datasets, it is perhaps a good idea to begin with a general overview of the ThinkGeo products that utilize various map datasets. This next section will provide a brief discussion of the .NET components in the Map Suite product line as well as an overview of Cygnus Track, ThinkGeo's resource and asset tracking solution.

Map Suite Products

The Map Suite 2.0 product line of .NET Development Components consists of Map Suite Desktop, Map Suite Web, Map Suite Engine, Map Suite Pocket PC, and Map Suite Geocode USA. The Map Suite 2.0 product line provides a set of mapping controls and tools that enable C# and VB.NET software developers to build their own geospatial applications for both desktop and web applications. Further, Map Suite 2.0 fully supports Microsoft Visual Studio 2005 and the .NET Framework 2.0.

Map Suite Desktop is a .NET mapping component that allows software developers to build detailed desktop mapping applications. Utilizing Microsoft's .NET Framework v1.1, the APIs for Map Suite Desktop Edition 2.0 incorporate the very latest technology to produce a versatile and user-friendly mapping component. In addition, Map Suite Desktop provides intuitive, streamlined interfaces to help make desktop spatial applications fast and easy. Cutting through the cryptic APIs, which are normally associated with building spatial applications, Map Suite Desktop offers the non-GIS developer the right tools to build spatial applications.

Map Suite Web Edition is an ASP.Net server control that enables C# and VB.NET software developers to build detailed internet mapping applications. Utilizing Microsoft's .NET Framework, the APIs for Map Suite Web Edition allow a developer to easily develop mapping applications on the Web in any of the .NET languages.

Map Suite Engine is a feature-rich low level .NET component that C# and VB.NET software developers can use to generate map images for presentations. Map Suite Engine features a non-visual component library that is specifically designed to generate maps. With this tool, developers can roll their own mapping control in Winforms or integrate a mapping solution with a legacy ASP web on the internet.

Map Suite Pocket PC is a .NET mapping component that enables C# and VB.NET software developers to generate mapping presentations on portable devices using the .NET Compact Framework 2.0. Map Suite Pocket PC features a sophisticated and easy-to-use component library that simplifies map building. By utilizing Map Suite Pocket PC, developers can build full-featured spatial and mapping solutions for Window CE devices and other portable devices.

Map Suite Geocode USA is a .NET geocoding engine that includes a highly optimized dataset encompassing the entire United States. Map Suite Geocode USA features a fast and easy-to-use .NET interface that enables C# and VB.NET software developers to take a United States address and quickly find its geographical location. In addition to geocoding, Map Suite Geocode USA also features reverse geocoding functionality which allows a developer to take a longitude and latitude point and find the closest address to that location. By writing just a few lines of code, a developer can integrate geocoding and reverse geocoding into a single software application. Finally, Geocode USA utilizes the most up-to-date TIGER® dataset from the U.S. Census Bureau to enhance its geocoding capabilities. This enables developers to geocode addresses anywhere within the United States.

Cygnus Track

Cygnus Track is a web-based GPS tracking application that enables owners to manage and track their vehicles and assets. Cygnus Track combines GPS technology, vehicle and asset tracking, and satellite communications networking to produce a GIS product that can be used to track vehicles, fleets, and other mobile assets through tracking devices. These tracking devices, such as cell phones or pagers, can be carried by drivers or mounted into the vehicles. Cygnus Track is based on an ASP.NET model and built on the Microsoft .NET platform, which allows the application to be accessed on any Internet browser, such as Microsoft Internet Explorer.

Cygnus Track is hardware independent, allowing owners to use current GPS tracking devices or the tracking devices of their choice. Cygnus Track can be integrated with any GPS tracking device and can be customized to integrate any geographical dataset, which gives owners maximum flexibility in their asset and resource tracking. Cygnus Track includes two types of map data for its maps: United States and World.

Map Data

Map data is simply the data that is required to represent a map, and data, in the general meaning of the term, is a collection of facts, information, and instructions organized in a format that enables it to be both communicated to and processed by a computer. This type of data format is referred to as digital data because it is data represented in a computer compatible format, which is a format that can be read by a computer. For map data and GIS (Geographical Information System) development, the following file formats are commonly used: Shapefiles, JPEG 2000, ECW, GeoTIFF, and MrSID. Finally, map data is often grouped in a dataset, which is a set of data that has a common theme or similar attributes.

Both Map Suite and Cygnus Track use map data from various map data sources in their applications. The Map Suite .NET Components utilize TIGER®/Line data from the U.S. Census Bureau to expand and enhance the capability and functionality of their map controls. For example, the Map Suite products can be integrated with mapping datasets such as TIGER® street data to enrich the GIS development process and expand the maps with more detailed features like road, railway, and county landmark features. In addition, Map Suite .NET components require a Shapefile (.shp) format for the map datasets used in their mapping and geospatial applications. Shapefiles are the most widely used file format in the GIS community and all of the Map Suite components currently support the Shapefile format.

Cygnus Track's design allows external high-resolution street and satellite maps to be integrated with its United States and World map datasets. The map data sources most commonly used in Cygnus Track data integration are Vector data, which must be in an ESRI shapefile file format, and Raster Imagery Data, which must be used in the following file formats: GeoTIFF, MRSID, ECW, and JPEG 2000.

In the following sections, TIGER® data and the main source for this data, the U.S. Census Bureau, will be discussed in detail as well as Vector Map data. Following these sections, the two major sources for premium map data—Tele Atlas and Navteq—will be discussed. Finally, at the end of this article, the two primary internet resources for map data—geodata.gov and data.geocomm.com—will be briefly discussed.

U.S. Census Bureau and TIGER® Data

With a history that stretches back to the early years of American independence, the United States Census Bureau is the leading source for reliable data about the nation's economy and people. The U.S. Census Bureau has the strategic goal of meeting the needs of businesses, policymakers, nonprofit organizations, and the public by providing current measures of the U.S. economy, population, and governments. Further, the activities of the U.S. Census Bureau include conducting large-scale surveys, updating geographic infrastructures, and collecting, processing, and disseminating data. To support its mapping and geospatial needs for Decennial Census, the U.S. Census Bureau developed the TIGER® system and digital database.

TIGER® is an acronym that stands for "Topologically Integrated Geographic Encoding and Referencing." The TIGER® format is used by the U.S. Census Bureau to describe land attributes such as roads, lakes, rivers, railways, landmarks, hydrology, and buildings. The topological structure of the TIGER® database defines the relationship of these land attributes to each other as well as the location of the attributes. The TIGER® database design is based on the theories of topology, graph theory, and related areas of mathematics in order to produce an accurate mathematical description of the geography of the United States.

The goal of the TIGER® database is to provide automated access to, as well as retrieval of, relevant geographic information about the United States. The U.S. Census Bureau uses the TIGER® System to automate the mapping and geographical activities used in its sample surveys and decennial census programs. In addition to this, the TIGER® System supports the creation and maintenance of a digital geographic database that covers the United States, Puerto Rico, the U.S. Virgin Islands, Midway Islands, American Samoa, the Commonwealth of the Northern Mariana Islands, and Guam. The U.S. Census Bureau also uses the TIGER® system to produce maps for its enumeration and publication programs and to assign individual addresses to geographic entities and census blocks.

TIGER® data files, also called TIGER®/Line files, are digital data that describes geographic features such as roads, rivers, lakes, railways, legal boundaries, buildings, etc. The TIGER® data files also contain information on the latitude and longitude of the geographic features, the names of the features, the types of features, the geographic relationship of one feature to the next, and the address ranges of most streets. In order to use Tiger® data in GIS development applications, a user needs to first import the TIGER® data by using either GIS or mapping software, such as a GIS toolkit, GIS SDK (Software Development Kit), or a map toolkit or map SDK. Finally, TIGER® data files are created by the U.S. Census Bureau's TIGER® database and are considered a public product. The most recent version of TIGER®/Line data is the 2004 Second Edition TIGER®/Line Files.

Vector Map Data

A vector is one method of data type that can be used to store spatial information. Vector data is an abstraction of the real world where positional data is represented in the form of coordinates, and the basic units of spatial information are points, lines, and polygons. Points represent X, Y, Z locations on the earth; lines represent anything that has a length; and polygons represent anything that has a boundary. Moreover, vector data is made up of lines or arcs, and the beginning and end points of these lines or arcs meet at nodes. Vector data stores geographical features that are defined by their boundaries and explicit topology. Finally, vector data models are the most commonly used spatial data models in GIS development. A vector data model represents a geographical feature as a row in a table, and each geographical feature is defined by an X, Y, Z location on the earth's surface.

Produced by the National Geospatial-Intelligence Agency (NGA), Vector Map, Vector Smart Map, or VMAP is a collection of databases providing vector-based GIS data that covers the earth at various levels or scales of detail. These levels of detail are levels of resolutions for viewing the earth and its geographical features. These levels are as follows: Level 0 (Low Resolution), Level 1 (Medium Resolution), and Level 2 (High Resolution).

Level 0 resolution (VMAP 0) is global coverage and in the public domain. This level also provides a worldwide coverage of geospatial data on a small scale of 1:1,000,000 and is available on CD-ROM or as a direct download from the National Geospatial-Intelligence Agency (NGA). Level 0 is an improved and updated version of NGA's Digital Chart of the World (DCW). The entire coverage for Vector Map Level 0 resolution is divided into four major datasets: North America (NOAMER); Europe and North Asia (EURNASIA); South America, Africa, and Antarctica (SOAMAFR); and South Asia and Australia (SASAUS). The data structure for VMAP follows the Vector Product Format (VPF).

Level 1 resolution (VMAP 1) is a medium scale resolution and features a dataset that is divided into 234 geographical titles. However, only 55 of these titles are available for download from NGA. Some of the datasets that are available for download from NGA include the following: United States, Mexico, Libya, Costa Rica, Russia, and Iraq. The scale of coverage for Level 1 is 1:250,000 and Level 1 VMAP is only partly in the public domain.

Finally, Level 2 resolution (VMAP 2) is a large scale resolution, which is a scale of 1:50,000. In addition to the levels of resolution, VMAP geospatial data is topologically structured and separated into nine thematic layers: boundaries, hydrography, elevation, industry, physiography, transportation, utilities, population, and vegetation. Each thematic layer contains a set of files that describes the features in each layer, and each thematic layer is stored as a single coverage. VMAP is designed to be used and analyzed by a GIS (Geographic Information System) and can also be used to produce map background displays for a wide range of situations.

Various tools can be used to read and convert VMAP data. For example, VPFView, developed by NIMA, can be used to render simple plots and export GIS data to other GIS file formats. VPFView is available from NGA as part of the NIMAMUSE package. Another tool that can be used is OGR with ODGI driver. OGR is capable of converting VMAP format to standard GIS file formats, such as Shapefiles. Since NGA is a government agency, nearly all GIS data created by NGA is free and openly available in accordance with the Freedom of Information Act. Therefore, much of the VMAP data is offered as part of the public domain. Although GIS data is open to the United States public, governments in other countries still view this data as a state monopoly, and it is strictly prohibited for use by the public.

The National Geospatial-Intelligence Agency (NGA) is the creator of the VMAP database system and is a Department of Defense combat support agency. The goal of NGA is to provide accurate and timely geospatial information to support national security efforts. In addition to this, NGA provides its customers with access to the world's best geospatial and imagery intelligence. NGA was established in 1996 under the title of National Imagery and Mapping Agency, but changed its name in 2003 to reflect its expanded function in the areas of imagery and geospatial intelligence.

Premium Sources for Map Data

There are several vendors of premium map data available, such as Tele Atlas and NAVTEQ. The map data provided by these vendors is readily available for integration with ThinkGeo's mapping and GPS satellite-tracking products.

Tele Atlas provides digital maps and digital map data for Geographic Information Systems (GIS), Location Based Services (LBS), and automotive navigation systems. Tele Atlas's map databases cover 51 countries and are available in a variety of formats. In addition, Tele Atlas provides accurate map data to support commercial and government mapping applications. One of Tele Atlas's products in particular, Dynamap, provides raw mapping data for end users to develop professional maps. Dynamap provides highly accurate digital map data that can be used in many GIS applications.

NAVTEQ is one of the world's largest providers of premium digital map data. NAVTEQ digital map data is most commonly used in vehicle navigational systems that are sold in North America and Europe. In addition to use in vehicle navigation systems, NAVTEQ's map data is also commonly used in numerous GIS solutions around the world. NAVTEQ digital map data features road geometry and dozens of road attributes in over 40 countries.

NAVTEQ data provides an accurate representation of road networks and up to 160 attributes, such as areas of restrictive access, physical barriers and gates, turn restrictions, one-way streets, and relative road heights. Besides the automotive industry, GIS development, and internet navigation sites, NAVTEQ data is also used in express mail services, efficient field management services, emergency and government routing plans, and vehicle tracking applications.

NAVTEQ digital map data is regularly tested by field researchers who continuously drive roads around the world to ensure that NAVTEQ data reflects current real-world conditions. Finally, NAVTEQ offers its users regular updates for its digital map data and these updates can also be added to older digital maps.

Internet Resources for Map Data

There are two primary resources on the internet for reliable map data. These resources are geodata.gov and data.geocomm.com. Geodata.gov helps users find data and map services, develop maps, cooperate on data acquisitions, and browse community information. The geodata.gov site is essentially a Geographic Information portal that is open to the public so that users can easily acquire geospatial information and data from a single source.

When a user registers with the geodata.gov site, searches, maps, and geography can be saved for later use. On the website, geography can be easily accessed for local governments and geographic data for federal, state, and local government can be accessed. GIS developers and users can access a wide variety of map data, such as live data and maps, downloadable data, offline data, and map files. In addition, data is divided into several different categories, such as administrative and political; farming and agriculture; biology and ecology; cultural, society, and demographic; geological and geophysical; and oceans and coasts. Finally, geodata.gov offers users several free GIS software tools like ArcExplorer Web.

Geocomm.com is another commonly used GIS portal on the NET and is an online resource for free GIS data to use with GIS and CAD software applications. Geocomm.com also offers free downloadable software tools and demos to help users get started with their GIS applications. Some of the GIS data that can be accessed from geocomm.com include: Digital Chart of the World (DCW), Digital Raster Graphics, Digital Elevation Model data, Landsat Thematic Mapper data, and Digital Line Graph data. The mission of geocomm.com is to be an online leader of geographic products and services for GIS developers and enthusiasts. The geocomm.com website promotes open and free exchange of geospatial information between users of the site.

In conclusion, ThinkGeo products, such as Map Suite and Cygnus Track, rely on map data from a wide variety of sources for their mapping and geospatial applications. For example, the Map Suite products utilize TIGER®/Line data from the U.S. Census Bureau to expand their look and functionality. Reliable map data is essential for the building and rendering of unique and accurate maps. In order to help customers realize the goal of building accurate, reliable, and unique maps, ThinkGeo has a staff of dedicated GIS developers and software engineers with extensive GIS experience, which ensures that map data integration is smooth and trouble-free. In addition to this, ThinkGeo uses mapping data from only the most reliable and accurate map data sources in the world, such as the U.S. Census Bureau.