If you agree with the old saying, “Many hands make light work,” you understand why crowdsourcing is an excellent approach for filling gaps and improving accuracy in maps. The practice has been used online for more than a decade and has proven highly effective in identifying and updating many types of geospatial information.

At the 2015 GIS in the Rockies conference, held in Denver on Sept. 23 and 24, the theme of crowdsourced data was present in both the “GIS in Government” track and the vendor showcase. Erin Korris from the U.S. Geological Survey (USGS) presented “Crowdsourcing the National Map: Volunteer Engagement and Data Quality.” In addition, Cindi Kalb, a senior geographic analyst from Here presented “The Here Map: Many Sources, One Map.” The main takeaway from both sessions is that adding community volunteers to the process of updating and validating maps results in a far better product and, not surprisingly, there are a lot of people willing to contribute to the effort. 

Crowdsourcing is not new to USGS. Between 1994 and 2001, the USGS Earth Science Corps enlisted the help of volunteers to update U.S. quadrangles. Approximately 3,300 volunteers updated quads by marking edits on hard copies and mailing (i.e., snail mail) the changes back to USGS. Although very helpful, the manual process resulted in a considerable time lag between the edits being received and actually being reflected in the mapping products.

More recently, in 2012, a proof-of-concept pilot project was conducted in Colorado to test whether USGS could recruit volunteers to perform online map editing and, if so, would the cost of validating the contributions and managing the program be reasonable? The answers to both questions were a resounding “yes,” which led to the successful implementation of a nationwide project in 2013. Today The National Map Corps operates in all 50 states, Puerto Rico, and the U.S. Virgin Islands. Volunteers are currently editing 10 structure types — including schools, fire stations, hospitals and post offices — and all edits are subjected to a rigorous validation process that results in a more complete and improved dataset for everyone to utilize.

“Editing every point for every structure type in the U.S. is a huge job — approximately 400,000 points exist in the database, and two-thirds still need to be checked,” says Erin Korris, USGS geographer. “We’ve recruited a really good core group of volunteers who are being directed to priority areas, and we continuously reach out to attract new volunteers to help with the work load.”

To ensure continued growth of the program, The National Map Corps is focused on three areas: recruitment, engagement and motivation. Recruitment is driven by advertisements on www.volunteer.gov, social media postings and USGS news releases. USGS staff members try to make it very easy to participate. The editing tool and all user guides are online. As technology has improved, the ability to process volunteer input more quickly has made the program increasingly popular.

Engaging with the volunteers is an important part of retaining participants. Through newsletters USGS communicates helpful tips, recognizes the accomplishments of volunteers, introduces USGS staff, identifies priority areas, and reports the status of new and updated points. For many, being part of a community of people with similar interests is an important reason to contribute. Many volunteers are retired mappers and long-term contributors from Earth Science Corps days.

To keep volunteers motivated, there are opportunities to earn badges and to move up skill levels to be an advanced editor. Gamification is also used to focus volunteers on priority areas while meeting deadlines. A recent mapping challenge coincided with the Oct. 15 Great ShakeOut that aimed to raise awareness about earthquake preparedness. The challenge called on volunteers to identify all types of emergency response facilities (fire station/EMS Station, law enforcement, hospital/medical center, ambulance service) and school points. Updates to the New Madrid (central U.S.) Seismic Zone will facilitate emergency response efforts in the event of a future earthquake.

Since 2012, The National Map Corps has received 160,000 contributions — either adding, deleting, editing or verifying a point — from 3,000 volunteers. “We are really excited about the release of a new vector web editor in early 2016 to streamline the editing workflow,” Korris says. “Volunteers will be allowed to edit a replica database. Unless an edit is flagged for further review, all changes will be included in nightly updates to the live database. It will mean a lot to our volunteers to see that their work is making an immediate difference.”

Crowdsourcing has also proved effective in maintaining and updating commercial databases, such as Here Maps. Here offers maps for more than 190 countries, voice-guided navigation for 131 countries and territories in more than 50 languages, and live traffic information for 50 countries. Operating globally adds a different level of complexity, but the basic concept of using crowdsourcing to refine and update the database is the same.

“The quality of Here Maps depends on the process being open, independent and focused on creating value,” says Dan Donovan, regional map and content manager at Here. “Our community program allows users to interact with a map and make hundreds or thousands of updates. The U.S. database is fairly mature, but things are always changing. There are still plenty of opportunities to provide input, and overseas there are many areas that need work. Most people have a lot of fun with it, especially when they travel.”

Original data is collected by driving with a six-camera mobile mapping platform installed on a vehicle, along with an inertial measurement unit (IMU) and a LiDAR sensor, with satellite imagery used as a base map. Supplemental data, such as center lines and addresses, are contributed by local government entities. The Here Location Cloud receives millions of daily updates from its global online community. Here’s internal goal is to review, approve and integrate edits within 14 days.

“Since 1997, private individuals have been able to notify us of errors via a tool called Map Reporter,” said Donovan. “In 2014 we released Map Creator, which takes Map Reporter one step further. Map Creator expedites the workflow by allowing end users to make edits directly on a map, which are then validated by our in-house team.”

Map Creator is designed for individual point updates. However, a supplier portal allows approved entities to provide larger volumes of data directly. The supplier portal is a perfect way for city or county agencies to contribute geospatial data that they want added to the Here database.

“In the Here vehicle navigation database we track over 240 attributes, including road names, height restrictions and traffic lights,” Kalb says. “It is a continuous process to keep this information up to date, and contributions from people in the community really improve our product and make it more useful for everyone. We highlight some of our most active contributors in the Here 360 blog. Many people participate because mapping is such a dynamic process. Everything is constantly changing. They see an opportunity to help other people by correcting mistakes, and if a new restaurant opens in the neighborhood, and they like it, they want to tell others by putting it on the map.”

Millions of people rely on geospatial databases, so the more quickly corrections and updates can be identified and implemented, the better. USGS and Here both recognize the value of soliciting input from the public as a means of tapping into local expertise to facilitate the process. Thousands of contributors worldwide are carefully adding, deleting, editing and verifying data points every day, and having fun doing it.

If you are interested in becoming a mapping volunteer, you can register for The National Map Corps at www.navigator.er.usgs.gov or Here at www.here.com/mapcreator.