Urban planning and decision making were very static before 3D city models were introduced to the world. By using a 3d city modeling aerial camera, experts can now foresee potential damage caused by a natural disaster, plan accordingly due to population changes and prepare for any changes in the structure of their city. A holistic look at the urban environment is required by city planners and they now mostly rely on equipment such as an aerial mapping camera or a 3d mapping camera. These tools help them gather very accurate and measurable data that can be changed, modified, and examined for better and more precise planning. These innovative tools help them acquire oblique images that have a big advantage over conventional, vertical view mapping. With access to the 3rd dimension, city planners have access to the most detailed 3D point clouds and 3D mesh models that help them make better decisions and more precise measurements. So how does all of this work and is your city missing out on this innovative technology? Let’s have a look.
Urban Mapping with 3D City Models
Photogrammetry and Lidar are the most common methods of acquiring 3D mapped models of any structure, building complex or an entire city. While they do produce similar results, they work in different ways.
Photogrammetry is performed by recording, measuring, and interpreting photographic images. Methods of optics and projective geometry are used to produce detailed 2D and 3D models alike. In simple terms, many images and recordings are made from a lot of different angles so that a 3D or 2D model can be recovered in post-processing. By putting these images and recordings together, city planners can obtain a clear 3D view of a structure and look at it from many different angles.
Lidar (Light Detection and Ranging) uses lasers instead of images. A 3D target area is illuminated by a pulsed laser and the information gathered is rendered as a 3D model of that structure or area. The difference in reflected light return time and wavelength can provide more than enough information that is used to create a very precise and detailed 3D model. This is all made possible thanks to 1,000,000 pulses per second that Lidar produces.
Almost all phases of construction can benefit from these mapping models because they can provide fast and very reliable data in real-time. Early groundworks are made easy with an aerial mapping camera because scrap, fill volume, and position can be easily measured. As the construction progresses, both techniques can be used to check if construction is going according to plan. Any anomalies in the construction process can be easily identified and addressed before they can even pose a problem.
Which one is better?
There are some obvious differences between Photogrammetry and Lidar so the best practice is to combine the two. Photogrammetry is highly dependent on daylight because it relies on light reflection. Capturing water, snow, foliage, and areas of concrete accurately is almost impossible with this technique. On the other hand, Lidar has an immediate drawback because it is unable to capture the true colors of the object that is captured. It relies only on the data provided by the lasers so color images are not an option. Different conditions require different approaches so both Photogrammetry and Lidar have their time and place in construction.
Conclusion
3D modeling is a complex and sensitive process. Without a proper 3d city modeling aerial camera and additional equipment, it can become an impossible task. Thanks to technological innovations in aerial imagery construction and urban planning have become more simplified and accessible. Cities that own the right equipment have a clear insight in their current situation and a perfect blueprint for further improvement and advanced problem-solving.
