Chapter 23

VGI & NeoGeography

The power of the crowd. Learn how volunteered geographic information and open-source mapping are democratizing the GIS industry.

At a Glance

Prereqs: Chapters 01, 05 Time: 20 min read + 25 min practice Deliverable: VGI quality critique

Learning outcomes

  • Explain what VGI is and why it can be powerful and risky.
  • Identify at least three VGI quality dimensions.
  • Design a simple QA plan using imagery or authoritative data as reference.

Key terms

VGI, completeness, positional accuracy, bias, conflation, metadata

Stop & check

  1. What is one reason VGI can be biased?

    Answer: Contributions are uneven across places and communities.

    Why: Participation varies by access, interest, and events.

    Common misconception: Crowdsourced means objective; it can reflect systematic gaps.

  2. How can satellite imagery support VGI QA?

    Answer: By providing a consistent visual reference for feature presence/location.

    Why: Imagery can help validate geometry and completeness.

    Common misconception: Imagery is always truth; it also has date, resolution, and interpretation limits.

Try it (5 minutes)

  1. Find one missing feature in a map you use (path/building/landmark) and describe how you would verify it.
  2. Write one sentence: what evidence would you cite?

Lab (Two Tracks)

Both tracks produce the same deliverable: a 1-page QA note evaluating a small VGI area (completeness, accuracy, and bias).

Desktop GIS Track (ArcGIS Pro / QGIS)

Compare a VGI layer to imagery for a small AOI. Mark 3 discrepancies and propose fixes.

Remote Sensing Track (Google Earth Engine)

Load imagery for an AOI and overlay a vector layer. Document 3 features that agree/disagree and explain why.

Common mistakes

  • Treating VGI as authoritative without checking.
  • Ignoring date mismatches between imagery and edits.
  • Conflating no data with no feature.

Further reading: https://www.ucgis.org/site/gis-t-body-of-knowledge

What is VGI?

Volunteered Geographic Information (VGI) is the harnessing of tools to create, assemble, and disseminate geographic data provided voluntarily by individuals. Instead of relying solely on professional surveyors, we now have millions of "citizens as sensors."

The "Wikification" of GIS: Just as Wikipedia democratized knowledge, VGI has democratized map-making, moving it from high-walled government agencies to the palms of our hands.

🎨 GIS as an Art: The Participatory Canvas

In VGI, the map is not a finished painting controlled by a single artist; it is a collaborative mural. Like street art, it is dynamic, sometimes messy, and deeply personal. The "art" is in the coordination—how thousands of individual strokes (edits) come together to form a coherent picture of the world.

OpenStreetMap (OSM)

OpenStreetMap is the greatest example of VGI. It is a free, editable map of the whole world being built by volunteers. In humanitarian crises, OSM often provides more up-to-date information than any official government source.

Geographic Inquiry: Asking Questions of Where

Before ever opening software, a GIS analyst starts with a question. "Where" is not just a coordinate; it is a relationship.

  • Concentration: Where is the phenomenon clustered?
  • Boundary: Where does it change sharply vs. gradually?
  • Uncertainty: Where is the data missing or biased?
  • Verification: Where would you stand on the ground to prove it?

🤝 Interdisciplinary GIS: Political Science

VGI disrupts the traditional power structures of mapping (a core theme in Political Science). By allowing citizens to map their own neighborhoods (counter-mapping), we challenge state-sponsored views of territory. This has huge implications for democracy, as "who controls the map controls the narrative."

Interactive: Crowdsourced Mapping

Click anywhere on the panel below to "volunteer" a location point. Notice how individual points start to reveal a pattern (the "Wisdom of the Crowd").

Points Contributed: 0
📢

Regional Decision: Crisis Mapping Harvey

During Hurricane Harvey in Houston, official flood maps couldn't keep up with the rising water. Volunteers created the Harvey Relief Hub map to track requests for rescue.

The Dilemma: You are a dispatcher. You see a "VGI" point on the map from a resident claiming their street is underwater, but the official satellite pass from 2 hours ago showed the street was dry. Do you:

  • A) Ignore the point because it's "unverified" citizen data?
  • B) Wait for the next official satellite pass to confirm?
  • C) Dispatch a drone or neighborhood scout to verify immediately?
Expert Insight: Most modern emergency managers choose Option C. In a "NeoGeography" world, citizen reports are often the earliest warning system. We use "VGI" to identify areas of interest and then use "Authoritative Data" to confirm.

Summary of Big Ideas

  • Citizens as Sensors: Every person with a smartphone is a potential geographic data generator.
  • Open Data fuels innovation and provides critical safety info in regions lacking official mapping resources.
  • NeoGeography: The use of digital maps by non-experts for personal, social, or humanitarian goals.
  • Quality Control in VGI is maintained through "Linus's Law"—the idea that with enough eyes, all data errors are shallow.
Critical GIS: The Participation Gap

VGI is often touted as "democratizing" mapping, but who actually has the time and technology to volunteer? Studies show the vast majority of OpenStreetMap contributors are young, male, wealthier, and from the Global North. This results in highly detailed maps of European cities but empty spaces in developing nations. "Crowdsourcing" is only as diverse as the crowd.

Chapter 23 Checkpoint

1. Which platform is widely known as the "Wikipedia of Maps"?

Google Maps
OpenStreetMap (OSM)

2. What is a primary criticism of Volunteered Geographic Information?

Variable data quality and inconsistency in metadata.
It is too difficult for ordinary people to use.

Chapter Glossary

Citizen Science: The collection and analysis of data relating to the natural world by the general public, often as part of a collaborative project.
Crowdsourcing: Obtaining information or input into a task by enlisting the help of a large number of people via the internet.
Geotagging: The process of adding geographic coordinates to media such as photos or social media posts.
← Chapter 22: AI Next: Chapter 24: Lifelong Learning →

BoK Alignment

Topics in the UCGIS GIS&T Body of Knowledge that support this chapter.