Stitching Close Up Warehouse Roof Photos

Has anyone tried creating an orthomosaic of a warehouse roof using very close photos like 15ft off the roof. Does it stitch properly or can there be portions of the roof without enough variation in the photos to allow it to stitch properly?

This is standard roof inspection stuff. Take 3-5 overalls looking straight down from slightly different positions. The whole roof in frame with a little to spare. Take one with the left side on the left edge, one centered and another right side right edge. Then take your closeups. Make sure to takeoff and accurately measure the top of the roof with the highest point in the center of the frame and then add 15-20ft to that. Run a normal mission with at least 80% overlaps and make sure to takeoff from the same elevation you did before.

You sure that will work on a roof that is 750,000 square feet? I suppose you may need to take a few more high altitude photos is all compared to a more typical warehouse size like 100,000 square feet.

With something that big, you will need to frame the width of the image to the shortest dimension and how ever many images it takes to achieve just over a 50% overlap.

The lowest you can fly with DroneDeploy is 66ft so depending on the height of the structure you may have to fly with something else. Also, at that distance from the roof you may need more than 85% overlaps to truly get more than 50% because of the lesser square footage the camera will actually see. All that said, I get over 5,200 images at 66ft and 85% overlaps so it would probably be in your best interests to quadrant the mission with 2-3 batteries per quad. Then you can stitch the quads together in QGIS for a giant master map. You will also probably have to manually bring the speed down to about 12-15mph, but you might be surprised at the detail you will get at 66 feet.

While you can’t yet do it with DroneDeploy, you might consider an oblique camera angle. You can run less overlaps and it will probably model rooftop structures better.

If you can find a lower location for you takeoff point, then you can fly lower over your building. The 66 ft limit applies to the takeoff point and not to what you are flying over. Probably obvious but I just thought I would point it out so you consider all available options.

Regards,
Terry.

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