senseFly recently held a webinar, Drone Surveying 101, where they dedicated some time for Q&A with\u00a0two client presenters: Marc Ca\u00f1as of Jacobs and Aidan O\u2019Connor of ASM Ireland. (You can watch the entire webinar for free on the senseFly blog.) Some questions they responded to are: \tWhat\u2019s the best overlap for stitching drone pictures? Marc Ca\u00f1as, Jacobs: That depends on what your output is\u2014if you\u2019re trying to get a high resolution digital ortho model or if you\u2019re just looking at imaging. What we\u2019ve found is that if it\u2019s just imaging and you\u2019re not really concerned too much with the underlying data\u2014you just want a great orthomosaic\u2014then you could really go down to a 60%-40% lateral on that, and that would be just fine. 60%\u00a0 \/ 40% \u2026 works actually quite well for orthomosaics But if you\u2019re looking at getting some higher accuracies in your digital surface model and digital terrain model\u2014depending on the terrain and depending on if it\u2019s urban or hilly, or whatever it might be\u2014you may need to increase that upwards of 75%. In general, 60\/40 for easy terrain, which is actually the default that the eBee defaults to, works actually quite well for orthomosaics. \tDid you encounter any resistance within the profession to using survey drones? Aidan: Resistance is not really the right word. They effectively do different jobs and generally traditional surveyors are more keen on surveying smaller areas to a higher degree of accuracy, millimeter accuracy. What we\u2019re generally doing is surveying larger areas to kind of maybe a 50 to 60 mil accuracy. So they effectively complement each other. For a lot of projects we go in as the first point of call. What we\u2019re generally doing is surveying larger areas to kind of maybe a 50 to 60 mil accuracy. So they effectively complement each other. Just recently, a project we worked on three years ago as an initial design has gone back out to traditional surveyors as they want more accuracy on stuff like bridges. So really what it\u2019s done is it\u2019s brought the use of manned aircraft, which were really only for bigger projects, it\u2019s brought that use down to the smaller project. The traditional surveyors are still in work and the majority of projects we work on, we work on together. Brock: Can I jump in there as well, just for a moment? It\u2019s quite interesting and I think it\u2019s an exciting time. We had the pioneers of this drone industry\u2014people like Aidan and like Marc and many other users\u2014who really went out there and proved this, proved the accuracy, proved the data and so forth. Where we are at the moment is we have over 320,000 flights that have been completed with the eBee platform. 12 million hectares, roughly, of coverage that we know of at the moment. So we\u2019re now at that next phase of that expanded growth. I think it\u2019s accepted. We\u2019re pretty well comfortable with the acceptance of this technology out there and we\u2019re now onto that next stage. Aidan: I\u2019d like to add, we\u2019re actually doing a lot of the jobs that surveyors generally didn\u2019t want to do, in so far as difficult terrain; terrain it was probably going to take you weeks to try and get a handle on, and generally not the nicest environment to work on. So generally we\u2019re kind of doing that type of work. \u2026 we\u2019re actually doing a lot of the jobs that surveyors generally didn\u2019t want to do Just yesterday, I got thanked by a surveyor that\u2019s been working in the industry for 25 years\u2014it\u2019s the work he used to hate doing, the big difficult jobs, rocks and landfill sites, areas where the environment isn\u2019t particularly hospitable. We\u2019re in and we\u2019re out in a day. These guys don\u2019t have to crawl over landfills and in safety areas, and quarries, we\u2019re taking that sort of risk out of it. A point cloud from one of Aidan\u2019s quarry flights: \tCan you put UAV use into perspective versus LIDAR aerial surveying? Marc: From my perspective, I\u2019ve evaluated both LIDAR and conventional photogrammetry. I think it\u2019s really simply put: aerial mapping from photogrammetry, or from a UAV, is more akin to your conventional aerial mapping and photogrammetry than it is to LIDAR. Aerial LIDAR is a completely different platform, where it does have more penetration down to the ground level. It is really a different technology and it\u2019s a different tool. I think they both have their applications and their uses, but they\u2019re definitely a different application. Aidan: I\u2019d just like to add that the big difference really with UAV technology, used in photogrammetry, is that what you\u2019re really getting is a surface model, so you do inevitably pick up stuff like buildings or heavy vegetation. LIDAR has the ability to penetrate through these, whereas we generally have to take these out manually. \u2026 the big difference really with UAV technology, used in photogrammetry, is that what you\u2019re really getting is a surface model What I\u2019ve found generally is that our accuracy on surfaces\u2014like roads or even on quarries, surfaces that are freely open\u2014are generally much higher and the coverage, again, it\u2019s specific. Generally, LIDAR data, from what I\u2019ve found, particularly if it\u2019s in Ireland, it can be quite old if it\u2019s off the shelf and it\u2019s quite expensive to get LIDAR data just for one particular project. So it\u2019s a gap we\u2019re filling. We generally don\u2019t have much of a problem filtering out buildings and trees and stuff like that you know. It\u2019s quite an easy process. It\u2019s just one thing to bear in mind that they are two entirely different technologies in effect. \tAidan, why did you use GCPs when the eBee RTK doesn\u2019t require these? Aidan: Well the main reason we used GCPs is because we\u2019re an early adopter of the technology; the eBee that we have doesn\u2019t have the capability to use RTK. Nowadays it\u2019s something we\u2019re actively looking at, especially the eBee Plus, it does kind of excite us, especially the PPK element. It\u2019s probably something we are going to upgrade to and we do see the benefit of it. The technology is evolving quickly but the RTK is special and it is a game changer again The eBee that we operate at the minute is actually the second UAV we\u2019ve had from senseFly. We had the swinglet, which was five years old or more, that was the first generation. The technology is evolving quickly but the RTK is special and it is a game changer again. It\u2019s something we will probably upgrade to next year I would imagine. This article originally appeared on the senseFly Blog, Waypoint.