Thank you @pablo for the info.
May I know how/what technology that is able to create those 3d maps? What I mean, how does a software or hardware is able to turn images from a camera into a 3d map? If a camera has gps-location capabilities; it only tracks the location the image it took, and the image is flat. What gives the information of the height and depth of objects in the photo?
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The camera does not need GPS capabilities itself, but if you want to connect a digital elevation model to the real world you need control points on the ground with known real-world coordinates.
Old-school photogrammetry was about triangulating points in different photos to figure out relative positions (stereophotogrammetry). It could be done painstakingly by hand, or more recently automated by computer program. A more complicated set of algorithms can be used to determine multiple camera positions and perspectives (and common features detected in multiple images) in software now referred to as "structure from motion." With it you can easily find thousands of points in space to define a 3D model. All you need is a bunch of photos. Photoscan is a commercial software to do this. Open source here: http://ccwu.me/vsfm/ And more expensive software with more capabilities is available through Leica or other GIS software makers.
https://en.wikipedia.org/wiki/Structure_from_motion
Example: http://culturalheritageimaging.org/Technologies/Photogrammetry/
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thanks for the clarification, as thats the reason of my original question wondering if it was possible for balloon mapping technique to get the 3d information. I thought the method of how drones did it was due to sensors in the drone that could detect distances to the ground as it flew over thus getting height/depth data.
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LIDAR is possible by drone, but it's a much more expensive technique and if you don't have a trained pilot and an excellent quality UAV you are putting a lot of money at risk. In most situations you are better off using expensive LIDAR equipment from a helicopter or fixed wing aircraft.
At this point I'd say photogrammetry is much better fitted to low budget operations with relatively high risk platforms (kite, drone, balloon). It also has the benefit of giving you color and texture data in 3D. LIDAR is used on drones by some professional groups though and provides unambiguous data that involves a little less processing and fewer stray 3D points.
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Juan Pablo Torrente has made several maps out of balloon and kite mapping https://sketchfab.com/bajaltura.com They are amazing 3D maps, like this one from Las Médulas in Spain https://sketchfab.com/models/88bb7c08a8104650ae3f3ed3b026e882 He made for us this 3D map of a square in Barcelona.
A commercial tool like PhotoScan can be used. It is a good opportunity to ask if people are using any open source software for post processing 2D images into 3D.
The software needs a good amount of photos from different angles and positions to be able to generate the 3D object out of all the 2D images.
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