Tag Archives: Visualisation

Urban X-Rays: Wi-Fi for Spatial Scanning

Many of us in cities increasingly depend on Wi-Fi connectivity for communication as we go about our every day lives. However, beyond providing for our mobile and wireless communication needs, the intentional or directed use of Wi-Fi also provides new possibilities for urban sensing.

In this video professor Yasamin Mostofi from the University of California discusses research into the scanning or x-ray of built structures using a combination of drones and Wi-Fi transceivers. By transmitting a Wi-Fi signal from a drone on one side of a structure, and using a drone on the opposite side to receive and measure the strength of that signal it is possible to build up a 3D image of the structure and its contents. This methodology has great potential in areas like structural monitoring for the built environment, archaeological surveying, and even emergency response as outlined on the 3D Through-Wall Imaging project page.

Particularly with regard to emergency response one can easily imagine the value of being able to identify people trapped or hiding within a structure. Indeed Mostofi’s group are have also researched the potential these techniques provide for monitoring of humans in their Head Counting with WiFI project as demonstrated with the next video.

What is striking is that this technique enables individuals to be counted without themselves needing a Wi-Fi enabled device. Several potential uses are proposed which are particularly relevant to urban environments:

For instance, heating and cooling of a building can be better optimized based on learning the concentration of the people over the building. Emergency evacuation can also benefit from an estimation of the level of occupancy. Finally, stores can benefit from counting the number of shoppers for better business planning.

Given that WiFi networks are available in many buildings, we envision that they can provide a new way for occupancy estimation, in addition to cameras and other sensing mechanisms. In particular, its potential for counting behind walls can be a nice complement to existing vision-based methods.

I’m fascinated by the way experiments like this reveal the hidden potentials already latent within many of our cities. The roll out of citywide Wi-Fi infrastructure provides the material support for an otherwise invisible electromagnetic environment designers Dunne & Raby have called ‘Hertzian Space’. By finding new ways to sense the dynamics of this space, cities can tap in to these resources and exploit new potentialities, hopefully for the benefit of both the city and its inhabitants.

Thanks to Geo Awesomeness for posting the drone story here.

The Art & Science of 3D Cities at the Transport Systems Catapult

Back in March I attended a day long workshop the at the Transport Systems Catapult (TCS) in Milton Keynes on the subject of ‘The Barriers to Building 3D Synthetic Environments’. The aim of the workshop was to bring together key SMEs and Academics to collaboratively identify challenges and discuss solutions for the creation of virtual environments that would be suitable for simulating and testing transport scenarios.

Alongside presentations from the Transport Systems, Future Cities and Satellite Applications catapults a number of SMEs also presented on topics as diverse as LiDAR data capture, GNSS positioning, 3D GIS and the use of GIS data in game engines. For my purposes the following talk on ‘The Art & Science of 3D Cities’ by Elliot Hartley of Garsdale Design was particularly interesting and raised a number of great points:

One of the key challenges for the generation and use of 3D data discussed by Elliot derives from the heightened expectation generated by the depiction of 3D urban environments in films, video games and Google Earth. The truth is the creation of these kinds of environments require considerable investment in terms of time and investment. Elliot’s talk poses key questions for stakeholders when embarking on a 3D project:

  • Why do you want a 3D model?
  • Do you actually need a 3D model?
  • What kind of 3D model do you want?
  • What 3D model do you actually need?
    • Small areas with lots of detail?
    • Large areas with little detail?
  • How much time and/or money do you have?
  • Will you want to publish the model?
  • What hardware and software do you have?
  • What’s the consequence of getting the model wrong?

While the primary focuses for the day were the practical and technical challenges of creating 3D environments, the further implication of Elliot’s discussion is that the use of 3D data and the creation of virtual environments can no longer be considered a purely technical activity with neutral products and outputs. For me the last question in particular foregrounded the stakes involved in moving beyond visualisation toward the growing use of 3D data in various forms of analysis. Thanks to Elliot for the stimulating talk.

After the presentations we had a tour of the TCS facilities and then broke up into work groups to discuss a number of themes. A report and summary is expected to be published by the TCS soon.

Pointerra: Points in the Cloud

Pointerra New York

Pointerra are an Australian geospatial start-up offering point cloud and LiDAR data as a service. Their platform which is deployed on Amazon Web Services enables online visualisation of massive point clouds in 3D via a standard browser.

The U.S. Geological Survey point cloud of New York visualised above has a massive 3.1 billion points. These can be navigated in 3D, viewed with or without a base map, and visualised by intensity, classification or height, as depicted here. Quality settings can be adjusted to speed up render times. Even on the highest setting the point cloud updates in a matter of seconds on our rigP.

Pointerra St Pauls

This second Pointerra example of St Paul’s Cathedral in London is visualised with RGB values. Being able to view point clouds on the web is great. With their plans to be “the Getty Images of 3D data”, as reported by The Australian, it will be interesting to see how the platform develops and what features get added over time. The platform isn’t yet live but you can try it here today.

This City: Controlling Urban Traffic Simulations With Sound

In the audiovisual performance piece This City designer Mark Wheeler has created an urban traffic simulation that interactively responds to his own live musical performance in real time.

In the walkthrough above Mark demonstrates how this was achieved using openFrameworks to provide the visuals with a custom sequencer and Ableton Live to control the the performance.

Inspiring work!