Ever wondered what’s beneath your feet as you walk down a city street? It’s not just soil and stone – it’s a complex, hidden web of water mains, gas lines, power cables, and communication networks that keep a city running. The problem? Most cities don’t have a clear or complete map of what’s down there. Despite its importance, underground infrastructure often remains poorly mapped and inconsistently documented. This lack of visibility carries serious risks: accidental utility strikes during construction, costly project delays, and slowed emergency responses during disasters.
And that’s where MUDDI comes in. Developed by OGC members, the Model for Underground Data Definition and Integration (MUDDI) is helping cities uncover, understand, and manage their underground assets with far greater clarity and coordination.
MUDDI is bringing order, accessibility, and interoperability to the fragmented world of subsurface data. In this blog, we unpack what MUDDI is, why it matters, and how it’s already shaping safer, smarter cities.
What is the MUDDI Standard?
MUDDI is an open, international framework designed to make underground infrastructure data findable, shareable, and interoperable. Developed by OGC members, it provides a common language and structure for describing subsurface features – pipes, cables, tunnels, and more.
It captures essential details:
- Multiple asset types like water mains, gas pipelines, sewerage systems, and telecom networks
- 2D and 3D geometry to map both layout and depth
- Temporal information to track historical changes and asset lifecycles
- Environmental connections to geological and soil data
MUDDI also integrates with OGC APIs, making it easier to link underground data with digital twins and other emerging technologies.
In simple terms, it offers a unified “family tree” of what lies beneath, bringing clarity to a traditionally fragmented and invisible domain.
The Challenges of Subsurface Data Today
Today, underground data is scattered across different utilities, agencies, and contractors, often stored in incompatible formats or incomplete records. This fragmentation leads to major operational risks – from accidental strikes to costly project delays and slower emergency responses
After 9/11, these risks became painfully clear. New York City’s responders needed urgent access to underground utility maps, but no comprehensive data existed. As Alan Leidner, who led the city’s geospatial response, reflected:
“It took us 10 days to piece together information about underground utilities after the collapse. That delay could have led to secondary disasters – fires, gas explosions, toxic leaks – because we simply didn’t know what was there. We learned the hard way that underground data isn’t a luxury; it’s critical infrastructure.”
Without standardized, accessible subsurface information, cities remain vulnerable to both everyday accidents and large-scale crises.
According to Scott Simmons, Chief Standards Officer, OGC, “Underground infrastructure is one of the most complex and least visible elements of the urban environment. MUDDI tackles this challenge by providing a common, interoperable framework that connects fragmented data across agencies, utilities, and technologies. It supports smarter policies, better planning, and more resilient cities—making the hidden systems we rely on every day safer and more manageable.”
How MUDDI Addresses These Challenges
MUDDI is designed to solve these longstanding issues by:
- Providing a consistent structure for organizing underground data
- Enabling cross-agency collaboration and system interoperability
- Integrating easily with GIS platforms, BIM models, and digital twins
- Supporting more efficient maintenance, smarter construction, and faster disaster response
Drawing from lessons learned in New York City, London, and beyond, MUDDI was developed through a practical, use-case-driven approach. It is not just a theoretical model; it is built to meet real operational needs, from routine street excavations to major disaster recovery.
Real-World Impact: Where MUDDI Principles Are Already in Use
The principles behind MUDDI are already being applied globally:
- New York City: Post-9/11 efforts to consolidate and map underground infrastructure have heavily influenced MUDDI’s structure and priorities.
- OGC Underground Infrastructure Pilots: These projects tested MUDDI-based models and APIs, showing real-world benefits in utility coordination and urban planning.
- National Underground Asset Register (UK): The UK’s NUAR initiative embodies the same values of interoperability and accessibility at a national scale.
- Ordnance Survey (UK): The UK’s national mapping agency is using OGC standards to improve underground data management and inform initiatives like MUDDI.
Alan Leidner captures the broader ambition well:
“Our goal is to move beyond isolated mapping projects. We’re working toward a continuous, integrated view of the underground – a living system of knowledge that evolves as our cities grow.”
What’s Next: Scaling Adoption of MUDDI
Looking ahead, MUDDI is set to power a new era of smart city infrastructure:
- Expansion into national frameworks through pilots and partnerships
- Integration with digital twins for real-time infrastructure monitoring
- Development of environmental extensions to address natural hazards like flooding and soil erosion
- Broader collaboration between public agencies, private utilities, and standards bodies
Scaling adoption will require more than technology – it will demand policy alignment, open data principles, and a shared commitment to building safer, more resilient cities.
Building Smarter Cities from the Ground Down
Resilient, safe, and sustainable cities must be built with the invisible in mind.
Underground infrastructure is vital to modern life, yet without standardized data models like MUDDI, it remains a costly blind spot.
MUDDI is laying the groundwork for cities that are not only smarter and safer – but also better prepared for whatever challenges lie ahead.
The future of urban resilience starts underground – and it starts with making the hidden visible.