Can anyone direct me to a discussion on available software used to extract planimetrics,contours and spot elevations from drone data? What kind of accuracy is available for areas covering 5,000 sq. ft. and flying around 100'? thanks for your help
We've done extensive testing for our needs, I believe the answer mostly comes down to ground sample distance, which is a function of flying height and image sensor. Here's a blog article I wrote about drone photogrammetric software being used to detect tree tops and the resulting accuracy.
There are many other variables that the average user doesn't even consider, such a camera ISO, which adds a random noise to all results. You then get into image overlap percentage which leads to confidence in the end solution. The fact of the matter is this software is capable of computing points that don't really exist with a high degree of confidence. Some people call this Pho-DAR, I call it Faux-DAR.
This is a very complex issue, there is no simple answer that X height = X accuracy.
In similar conditions we have found 160ft AGL with 80% front/side overlaps, and 4 or more GCP's to yield best results using a drone with 12.4MP camera.
Of course you need to know your surroundings to be able to fly at this height. Similar to GeoPro findings the light poles, dead trees and objects smaller than the GSP will not show well in the point cloud.
Works good for sand pit topo. Here is an example of a sand pit 3d model from point cloud. This flight took about 9 minutes, taking 250 photos (3000x2000)
Accuracy also depends on ground cover - heights to hard surfaces will be more accurate than to vegetation. (Roads beat long grass in other words)
