At Albion Surveyors we have been commissioned to inspect a whole batch of properties in London to provide measured surveys of the roofs and to produce 3D mesh models of each building. We use photogrammetry from the drone photographic data and clever software. Isn’t tech wonderful. It certainly impresses our clients. 10 years ago none of this would have been possible. We were measuring buildings using hand-held lasers then. Anyone out there had a similar experience?
Sounds interesting, I may have to look into that. Do you have to take any measurements of does it work it all out from the drone shots?
It mostly works it all out from the photos, though for improved accuracy, ground control points can be used and / or a Real Time Kinematic (RTK) positioning equipped UAV.
For direct measurement a LIDAR equipped UAV can be used.
Yes, for 3D models and for things like Ortho mapping.
Even using just visual spectrum you can pull out very precise measurements and from a archaeology point of view, reveal hidden features. And thats without Lidar, thermal etc.
The lack of SDK support has hampered more recent drones (and when it does come, people like Drone Deploy dont seem interested in updating) though.
I have a P4 RTK (and RTK base station) that I’ve used for hobby surveys. For example, I surveyed a local iron age hill fort a while back, and more recently our house roof.
For the roof I used the point cloud and mesh to take measurements (which were within a few cm of physical tape measure), and also used it to model the layout of solar panels and do some basic solar shadowing studies (in Blender).
I recently bought a Mini 3 Pro for general photography and video.
I’ve been thinking of going for A2CofC then GVC to see if I can do some commercial work on the side.
Most of my interest in it had been driven by wanting to learn a bit about geodesy and photogrammetry.
The hill fort survey was cool, because I used it to test the terrain following feature of the flight planning software. In that case I loaded a patch of public LiDAR data; when the drone flew the survey, it followed the contour of the land. 
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I have made a few 3d maps with the air 2 using map pilot pro. Been very easy to use. Can be expensive if you do more than a 1 gigapixle map.
One of my favourites, old castle site with almost nothing visible at all on foot walking around.
The aerial helps but the DEM really shows the old room layout, doors and shape of the now grass field.
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I do a lot of drone photography of boring stuff like buildings (roofs, facades, whatever) using a M3P.
I’ve been dabbling with photogrammetry, but at the moment I’m disappointed (yup bad tradesman blaming tool… err FREE tools!)
tried meshroom… but it doesn’t like my laptop (no Nvidia / cuda GPU)
currently trying Open Drone Mapping (ODM), paid version for easy install. https://www.opendronemap.org/
what I noticed was my high resolution images seemed to turn into very poorly pixelated images.
I appreciate that ODM (and photogrammetry) is trying to stitch images together and blend them to form either a 2D plan or 3D model… but what I’m getting is very pixelated… I suspect that I probably did not have enough images for a smoother blend as I tried a pack of 53…
I’ve got another site that I took a while lot more (about 300)
for those of you that have mastered this… what are your suggestions for a high quality image (2D stitched) or mode 3D.
these are fairly big buildings (the one with 53 images, was about 1500 m sq, single storey mostly with a second storey where the ground fell away… but I was really only interested in the single storey portion). the purpose of those images (and stitched dataset) was to inform a design team of the external facade + what was on the roof… think of an aide memoire to check whilst carrying out an (internal) refurbishment and remodeling… so that they could see where the roof lights were so they could be removed if needed… external lighting so it could be replaced… lightning protection so it could be inspected for coverage and integrity)
the one with 300 images was to allow for external facade snagging and defects inspection post construction (time of handover), hence really I’m looking for a very high image resolution but sort of a stitching of the images as my present workflow (very inefficient!) is to review each image and circle or mark every defect and denote a comment where required or a number which can be cross referenced… problem is… the images overlap… hence comments can be repetitive.
yup whilst I’d like a paid price of software… believe it or not this is just a “hobby”… the drone is just a tool, the same way as I use a phone camera, 360 camera, tape measure, laser measure, air flow, volume and pressure meters, water flow meters, electrical testers and circuit verification tools, etc etc. they are all personally owned and used to speed up the process of obtaining information that can be assessed to remove guess work and approximation … hence a paid subscription or something costing a hell of a lot is not justifiable.
I spotted https://lumalabs.ai/ , not used it yet, but it seems to only like video clips… I don’t really use video, due to the file size and it’s not as great as a high resolution image. (tried to video on the building snagging but it suffered from motion blur even at very low movement and huge file sizes!!)
any suggestions?
Sounds like a mismatch between its estimate of ‘ground sampling distance’ and the actual cm/pixel resolution of your image.
There is an option to tell ODM to stop using its estimate, but it does increase processing time - set ‘ignore-gsm’ to true in the run options, then set ‘orthophoto-resolution’ to the real cm/pixel value
If you are also producing a Digital Elevation Map, set ‘dem-resolution’ correctly too
If you are unsure of what your cm/pixel resolution is, an easy way to guesstimate is to use the free Dronedeploy app, put in the drone/distances to target you took the photos at and it will give you a ballpark figure
Hope that helps
Metashape. 30 day trials available.
The standard version isnt that extortionately priced at all, the pro version (orthos etc) is.
If you’re smart you can install the 30 day trial of standard, use that until expiry THEN install pro for another 30 day trial so get 60 to experiment.
But you’re going to struggle - photogrammetry ultimately is vast amounts of number crunching. If done locally its going to need a good GPU, ideally with CUDA cores (ie nvidia).
The amount of data crunching is vast.
thanks @ximi and @gnirtS , I’ll give it a shot
(looking at replacing my laptop with one with an Nvidia GPU anyway)
All from the drone shots and then loaded into special software. Amazing.