To build a city, you must first start with its “spine” — its roads. The roads leading into it, out of it and within it. Walk with me as I tell you the story of VELOCITY, a virtual environment software solution created by Presagis, an Esri silver-tier partner based out of Montréal, Québec.
Having established itself solidly in the fields of civilian and military aeronautics through the delivery of simulation and graphics software, Presagis continues to challenge the status quo. The creation of VELOCITY is an example of just that. It’s a geodata-centric solution, which automates the production of urban spaces, with minimal to no human intervention other than possibly pressing the “Enter” button to begin the process.
In the world of simulators, the details of what you see depend on your altitude, speed and type of mission. You will only see basic terrain if you are flying a fast jet. While at an altitude of 5,000 – 10,000 ft. in a helicopter simulator, rooftop details such as air conditioners, water tanks and so on are visually apparent. On the other hand, ground simulators need to provide the trainee a more realistic picture of the ground scene with its building details, vehicles, roads and so on.
Conventional simulation production requires human involvement to build, fix and adjust the environment, which is both labour-intensive and repetitive. Presagis pushed the envelope with VELOCITY by fully automating this process. An organization’s geographic information system (GIS) and 3D data are fed into VELOCITY to create a believable environment of large areas or countries.
Dave Lajoie, system architect and the wizard behind VELOCITY, explained that “to simulate an urban scene or city, you must first begin with its roads because they are the ‘spine’. Roads are also the veins upon which human interaction and activities in the city happen.”
His team used GIS road data available on OpenStreetMaps, which posed both free and expensive at the same time. Although the data is unlicensed making it free to use, Presagis spent time and effort cleaning it up before they could actually use it. The first snag was data vandalism, a result of crowdsourced data, and the second was the different naming conventions of attributes. For example, there were 14 different spellings for “asphalt”. Data was cleaned up within VELOCITY, and Presagis had good vectors. The actual generation of a road was the next step.
Presagis understood that generating a simple road intersection would not pose a challenge. The difficulty is how to process a large amount of data to re-create intricate angled intersections and end-junctions, which are more representative of real-life urban spaces.
The company looked at Esri’s CityEngine to resolve this issue. It’s a smart 3D visualization tool for city modelling, game development and film production, among other things, that’s also capable of processing lots of data at the same time.
Presagis collaborated with the CityEngine R&D team in Zurich to test the full capabilities of the application. They set about to find the most complex road network available on OpenStreetMaps: the Huangjuewan Overpass in China, with five road layers and more than 20 ramps. The data was churned into CityEngine to create a digital twin of this massive highway.
The Huangjuewan Overpass replicated by Esri’s CityEngine
The result was testament to both CityEngine’s ability to digest vast data into 3D and the team’s choice of CityEngine as a tool upon which they would develop their API.
Next came simulating an actual city, Singapore. Why Singapore? Singapore provided Presagis the best training start for VELOCITY. It has the right mix of everything: complex urban spaces, landmarks, waterways, bridges and much more.
To build the city limits, the team broke down the city’s road network into smaller more manageable tiles using VELOCITY and CityEngine in the background. The outline of city blocks needed filling by identifying the attributes or details in each plot. However, they quickly realized that some of this data was unavailable on OpenStreetMaps. Again, the team reverted to CityEngine to create city lots, cadastral and parcel, which were atypical of Singapore but provided a rule-base sub-division for areas with missing data. CityEngine generated approximately half a million lots in a short turnaround time. Within this automated process, the team only hand-generated 30 landmark buildings.
Presagis also collaborated with LuxCarta, a geodata provider, to fill in additional details of the virtual Singapore. LuxCarta data offered very precise building footprints along with building heights. This geo-specific data allowed Presagis to rebuild or restore exact building shapes in VELOCITY. To procedurally extract surrounding missing plots, Presagis combined the LuxCarta data with accurate 3D surface models, point clouds, shorelines and multispectral imagery provided by another company called Vricon.
2D map with all three data sources; CityEngine, LuxCarta & Vricon (above) against the VELOCITY output (below).
Vegetation was another detail Presagis took into consideration. “Nature is an excellent designer,” said Dave. Tree ecosystems give a unique visual that needed to be emulated in VELOCITY. The Vricon data enabled the team to both analyze tree location and volume to restore the canopy silhouettes into a more believable terrain. A filtering algorithm was written to guarantee the proper placement of trees in the ground and not have them branch out off buildings or streets.
This amalgamation of CityEngine, LuxCarta and Vricon data into VELOCITY allowed Presagis to produce an enhanced visual of Singapore.
Road to Perfection
Depictions of the urban scene such as the different light shades over the city horizon – be it dawn, morning, dusk or night – and varying surface materials such as wood, glass and metal were not missed by Presagis and were added through extra data processing. The virtual Singapore that would have taken days, or more likely weeks, to create was completed by VELOCITY in mere hours.
Just like the road Presagis started with, VELOCITY isn’t the final product. It will continue to expand and develop with future enhancements. For now, VELOCITY is the assembly line; it’s the data factory or the automated kitchen where all the ingredients are baked into perfection.
A majestic sunset in VELOCITY’s Singapore. Click on the picture to watch the VELOCITY video.
Have I managed to spark your curiosity to learn more? I hope I did. Learn more about VELOCITY.