Urban Planning and Digital Experiences

How 1960s Urban Planning Principles Influenced Digital Products, Services and Connected Spaces.

Tron Credits — GMUNK

Tony Fadell, the design innovator who led the development of many successful products at Nest and Apple, often talks about the importance of noticing frustrating moments. This might include the annoying task of peeling those little stickers off of fruit. Produce stickers were added to help with grocery scanning, but this step drives all of us crazy once we are at home. After identifying these moments, a solution can be explored. But how do you quickly recognize and identify the source of the problem for a complex connected product, service, or space?

When I’m confused using a mobile application, or not sure how to find an exit when leaving a building, or trying to get my bearings in a new part of a city that I’m visiting, I often think of PEDNL. PEDNL stands for paths, edges, districts, nodes and landmarks and the term gained popularity more than fifty years ago in the urban planning community by MIT professor and author Kevin Lynch. It can can be used as a simple way to better understand digital products, services, physical spaces and cities.


For designers and technologists who worked through the rise of the “commercial” internet in the mid 1990’s, “borrowing” approaches from related fields was a common practice. The industry was growing at a speed such that teams needed to speak in a language that was common to their clients, investors, and each other. The excitement around the rise of internet innovation attracted industrial designers, architects, and graphic designers, among others. Over time, our blended language, methods, and tools reflected these diverse backgrounds. Practitioners used the language of the physical world to make sense of new digital assignments. Wireframes, which resemble building blueprints, became tools to plan out a software application. Information Architect became a common job title. From software to mobile applications, the form of these digital interaction expanded and were ironically used to change human behavior. These new forms enticed people to spend less time looking around their environment and more time looking down at a variety of displays and devices

In recent years, internet connected objects such as Amazon’s Echo, which follows audio commands, and responsive signage that can sense surging crowds and help redirect people for better flow, are again changing our relationship to technology and spaces. The line between digital services, spaces, and cities is blurring. but the PEDNL checklist applies.

The five elements of PEDNL can be credited to Lynch in his 1960 book The Image of a City. He makes a case that people orient themselves by means of mental maps. Mental or cognitive maps help people make some sort of personal sense of the world, where they’ve been against the places they’ve never seen before. Mental maps are a way of combining our objective knowledge of places in addition to our subjective perceptions, or opinions, of locations around the world. A clear mental map of an urban space is needed to counter disorientation (source). Lynch suggested that these mental maps consist of the following:


Paths: The streets, sidewalks, trails, and other channels in which people travel. Lynch noted that paths were often the predominant elements in people’s mental maps with the other elements being arranged and related along paths.

Edges: May be barriers, more or less penetrable, which close one region off from another. Edges can also be seams, or lines along which two regions are related and joined together.

Districts: Areas characterized by common characteristics, districts often related to large areas of land, which observers mentally enter ‘inside of’ and/or have some common identifying character. Some examples may include Industrial Zones, Residential Neighborhoods, and large parks.

Nodes: The strategic spots in a city into which an observer can enter, and which are the intensive foci and from which the person is travelling. (Note: I often think of nodes as wayshowing elements such as street or subway station signage)

Landmarks: Landmark’s key physical characteristics was singularity some aspect that is unique or memorable in the context. Some landmarks — towers, spires, hills are distant and are typically seen from many angles and from distance, over the top of smaller elements. Other landmarks — sculptures, signs and trees are primarily local being visible only in restricted localities and from certain approaches.

Lynch was able to use this image of a city and his PEDNL elements to influence generations of civic planners. How does this relate to current digital service and product design challenges?

Zoom down from Lynch’s bird’s eye city view. Imaging you’re now in a retail store. Think PEDNL You have your paths (aisles), edges (parking lot, back of house), districts (changing rooms, checkout, etc), nodes (wayshowing signage). For confusing spaces like this you often hear that the service design or store flow is lacking. Use PEDNL the next time you’re conducting a service audit. How does the mental map of a new customer differ from an exiting customer?

Continue to Zoom down. Now imagine that you’re holding your phone using an application. PEDNL applies. Every piece of software that you use has an intended path that designer wants you to follow. Landmarks and Nodes help you pass through districts such as welcome pages, account set-up, product inventories, and payment states. For confusing digital experiences like this you often hear that it poses “usability challenges”. Use PEDNL the next time you’re conducting a experience audit.

Example of Application User Flow / Mike Pons

Lynch’s urban planning frameworks can help designers and technologist to make sense of a new digital world and discovery opportunity areas to make improvements. When we can adjust our perspective to rapidly think through the space, service and device level interactions. New systemic solutions emerge. As technology continues to redefine digital services and spaces, we are again using Lynch’s principles to impact the physical world he focused his life on improving.