The National Map Corps Pilot Projects

USGS Workshop on volunteered geographic information (VGI)

The USGS held a workshop on volunteered geographic information in January 2010. The goal of the workshop was to learn more about programs that had successfully used volunteers to collect data.

The workshop included representatives from organizations that ranged from citizen science efforts (e.g. NOAA’s Cooperative Observer Program), to online crowdsourced identification of historic photographs (e.g. Library of Congress), to commercial firms such as TeleAtlas that update street networks by placing sensors in volunteers’ cars, and OpenStreeetMap (OSM), a non-profit venture to build an online map of the world with volunteered data.

Discussions at the workshop raised a number of questions that must be explored before the USGS can reestablish a viable volunteer program. These include:

• the accuracy of volunteered data
• choosing suitable tasks and structures for volunteer data collection
• motivating volunteers and providing incentives
• integrating volunteered data with official data
• cost/benefit trade offs
• sustainability of volunteer programs.

OpenStreetMap Collaborative Project, Phase One

As a result of the workshop, the USGS initiated an experimental project, the OpenStreetMap Collaborative Project (OSMCP), to address some of these questions and to test the viability of using VGI to improve The National Map.

Phase One of OSMCP evaluated the suitability of existing web-based collection systems for USGS VGI efforts. In this phase, USGS created a system to support collaborative editing for transportation (roads) data with a USGS partner but did not incorporate volunteer contributions.

A prototype was built using the open source software that supports the OSM system.

This software was chosen for several reasons:

• it supports web-based editing via a variety of browsers
• there is a simple user interface that can be used effectively for "heads-up"digitizing¹ with a minimum of training and user documentation
• the costs are low and the software is deployable on existing USGS hardware
• there are no requirement for data contributors to have a software license
• the software can be customized to support all the editing functions required to incorporate data into The National Map.

This software was replicated, deployed, and customized on a USGS system.

The USGS partnered with the Data Access and Support Center (DASC). of Kansas to test whether this software was appropriate for collaborative editing, and whether the data produced met USGS specifications for accuracy, completeness and conformance to the USGS "best practices" data model. Editing and data improvements were focused in Douglas and Johnson counties in Kansas. These counties contain a mix of urban and rural areas.

The editing software runs in a web browser with a backdrop of aerial photography provided by the National Agricultural Photography Program (NAIP). The software was used in a heads-up digitizing mode to update the existing state roads database which lacked many interchanges, divided roads and attributes. The work process was as follows:

• Specifications for editing based on the USGS Best Practices data standards were drafted and shared with the partners.
• Road data for the entire state of Kansas aggregated by DASC was loaded into the database.
• The initial area of interest (Douglas and Johnson Counties) was selected.
• Interstates, US Routes, Ramps and Service Roads were edited by USGS personnel in Denver, Colorado.
• State Routes were edited by DASC personnel in Lawrence, Kansas.

The first phase of OSMCP resulted in a roads database for the two Kansas counties that was of suitable quality for both partners, adding missing interchanges, divided highways and attributes to the existing Kansas roads database.

The OSM software proved to be easy to use for co-editing by multiple organizations in a distributed environment. A more detailed report can be found online.

OSMCP Phase Two

In the second phase of this project, the USGS is working with non-professional contributors, engaging GIS students at Denver-area colleges and universities to systematically collect 30 types of structures data for four 7.5-minute USGS topographic quadrangles in the Denver area: Arvada, Commerce City, Fort Logan and Englewood.

Structures data were chosen for this phase because they are less complex than roads data and thus easier for non-professionals to edit.

This project will track costs and benefits by comparing the results of traditional data collection methods to volunteered data collection methods.

Another important goal of this phase is to ascertain whether "volunteer editors" drawn from the ranks of users, such as those used by Wikipedia.com, can provide quality control to data collected by non-professional users with the editing software described above.

Additionally, quantitative methods for estimating the number or percentage of structures that are wrongly attributed or that are omitted from the database will be explored.

This phase will also allow the USGS to evaluate the usability of the OSMCP interface for non-professional users. A report on this phase of the project will be posted on this site at the conclusion of this phase.

¹Heads up digitizing: the process of tracing feature outlines from an image on a computer screen.