hi, I am new here in the forum.
recently, I am doing research focus on UAV and BIM. I use DJI phantom 3 standards to conduct photogrammetry, using Ipad and Pix4D capture.
I have a problem in surveying using GCP, because have no experience on it. so when doing photogrammetry I don't really care about GCP.
I process images using Agisoft.
I tried to combine the data from Agisoft to some software?ÿI found from other forums, but it makes me be more?ÿconfusing on what i am doing.
can anyone here help me to solve my problem?
my basic idea is, start from Agisoft, I want to analyze whether the building is ok or not, then do recondition on the building.
thank you for your help.
What I read is that you already have a discussion and a topic. Expand on what you know and want and research what you don't know or want to do and find reason for why it is connected and/or needed for others.
Not of any help because none of what you said is relevant to my surveying business model.
haloo, thanks
after all this time, I became confused by what I learned. in your opinion, what can I develop from this problem?
More problems.
Maybe wrong tool, right job, or right tool, wrong job. Or, technology will solve it for you.
N
and, can I do photogrammetry without setting up GCP?
really I need advice
and if I have to set up GCP, what should I do first?
from what I have read, I have to use surveying tools to set up GCP
the problem is, my team, they don't have related experience on surveying. and no surveying tools.
My understanding is that it is possible to do photogrammetry without ground control points. It is done by getting the camera's position at the time each photo is taken using RTK. But that is tough to do with full sized aircraft and possibly it not even available on drones. I don't know . In any case, because of the difficulty of positioning the moving aircraft/camera at the exact instant of exposure, such work tends to be of lower precision than work done with GCPs.?ÿ ?ÿ
My understanding is that it is possible to do photogrammetry without ground control points. It is done by getting the camera's position at the time each photo is taken using RTK. But that is tough to do with full sized aircraft and possibly it not even available on drones. I don't know . In any case, because of the difficulty of positioning the moving aircraft/camera at the exact instant of exposure, such work tends to be of lower precision than work done with GCPs.?ÿ ?ÿ
RTK and PPK are widely available on drones. Accuracy depends partly on the fact that a typicla flight may have 500 or more positions and when these stitch together accuracy benefits from the mass of data. However GCP's will always improve the result and in some cases may rescue data which otherwise will not compute to any degree of accuracy.
so, if GCP is helpful....based on my problem, what are the simplest method to make GCP.
(no experience and not many tools for setting up good GCP)
thank you in advance
Simplest is a can of white paint. Make a cross - depending on your camera 1" wide each arm 6" long may well do. (Check out by painting one on a wall and photographing from your normal flying height. After marking, survey positions with GPS or a total station. If you have no survey experience then you might need to get somebody to do this for you.?ÿ For small sites, which you appear to be interested in, one GCP in each corner will do. For larger sites keep the spacing to under 200m.
For slightly larger ones which don't need to remain after the flight cut up cardboard boxes and do the same.
For long term use corrugated plastic sheet (yellow or white) with crosses made from electrician's black tape, or similar. Use two thicknesses of sheet, at right angles to each other and glued thoroughly. these will resist most wind. Fix to a centre peg using a large screw and metal washer. Even if the board eventually goes the peg will probably still be there and you can just fix another board.
Agisoft manages to combine aerial images with ground images quite well, so you can fill in the elevation detail on buildings b y walking round and taking photos.
?ÿ