GEOG 497C
Transportation GIS

2.1 Roadway Data Sources Used in GIS-T

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Roadway data are fundamental to GIS-T and many of the most important transportation modes (e.g. highway, transit, bike). Many GIS functions and analyses rely on it including geocoding and network analysis, both of which we’ll take a close look at in the next few lessons. Roadway data also play an important role in mapping and visualization for many GIS applications.

There are a number of commercial and public sources of street data and services which are available. Some are public and freely available, and others are commercial. In this lesson, we’ll take a look at some of the most widely used sources of street data.

Public Sources

TIGER Data

TIGER is a data source produced and published by the U.S. Census Bureau. These data include street data which can be used to perform geocoding or to produce a street network. TIGER data were used as a “seed” for many of the other roadway data sources, both public and commercial. We will take a closer look at TIGER data later in this section.

OpenStreetMap (OSM)

OSM is a rapidly growing Volunteered Geographic Information (VGI) project which got its start in 2004 and is sponsored by the OpenStreetMap Foundation. For U.S. roads, OSM initially used TIGER Line files but many updates have since been made based on input from its volunteer community which is now over a million strong. In some parts of the world, OSM data are as good, or nearly as good, as its commercial counterparts.

Agency-Generated

State-level transportation agencies have long maintained road centerline networks as well as additional networks for other modes. They have been improved greatly in accuracy and precision, and agencies are increasingly adding local and private roads and associated data. Much of this latter impetus is due to increased federal requirements for data collection and reporting. In most cases, these networks are the most complete and accurate product for network features and associated attributes for any given state.

Transportation for the Nation (TFTN)

TFTN is an evolving governmental initiative from the National States Geographic Information Council (NSGIC) and USDOT that originated in 2008. TFTN will initially be a road centerline dataset that may replace overlapping federal efforts and products. A set of centerline datasets has been created as part of state DOT submittal requirements for FHWA’s Highway Performance Monitoring System (HPMS). The next step is to try and join these across state lines.

Commercial Sources

TomTom / Tele Atlas

Tele Atlas was founded in 1984 and was acquired by TomTom in 2008. Tele Atlas data was primarily collected from its own mapping vans. The company’s road products are decreasing in importance and usage.

Nokia / NAVTEQ / HERE

Founded in 1985 and acquired by Nokia in 1991, NAVTEQ (now renamed HERE) operates independently and partners with third-party agencies and companies to provide its networks and services for portable GPS devices made by Garmin and others, and Web-based applications including Yahoo! Maps, Bing Maps, Nokia Maps, and MapQuest.

ESRI StreetMap and StreetMap Premium

ESRI does not produce road data directly but instead acquires it from HERE, TomTom, and others and repackages it. ESRI StreetMap covers North America and is part of Data and Maps which is included with ArcGIS. StreetMap premium has more current data than StreetMap and also has coverage for Europe.

Google

Google has become a major provider of mapping services. Google doesn’t make its street data available directly but instead uses it to provide services. These services are provided through products such as Google Maps, Google Earth, and various APIs. In 2008, Google released a tool called Google Map Maker to encourage individuals to submit or correct feature information. This is similar in concept to the manner in which OSM derives much of its data. Google retired Map Maker in 2017 in favor of its "Local Guides" program. As a "Local Guide," you can contribute reviews of businesses or places, upload photos and suggest a new place. Recently, they also began to add capabilities to allow users to report issues with roadway geometry and missing roads. Local Guide contributions are all made directly in the Google Maps interface. Take a look at these comparisons between OSM and Google in regards to the services they provide and their user contributions programs. One should note these comparisons are published on the OSM Wiki site so they may be a bit biased.

Also, check out this map comparison tool made available by Geofabrik, an organization who promotes OSM and provides a portal for downloading OSM data extracts. Select an area you are familiar with, and compare the OSM map, the Google map, and the HERE map.