Arun,
This post from @igor.vereninov lists some use cases that will be of interest…
I am not sure about current DJI integration status. My understanding is you would need to run the Reach as a separate device with it’s own radio as 3rd party integration with DJI is a bit challenging. Not sure you can get shutter event from a DJI branded camera.
Most of the people we work with are favoring a Sony A6000 since it has a nice 23MP sensor with hot shoe for shutter event timestamps. I would guess you could make a Phantom 4 fly that rig with a Reach.
I would say you may want to take a look at their Matrice over a Phantom if you really want a DJI. It’s being designed for your use case, among others. You just need to know whether being locked in to a vendor’s tech is worth the relative turn-key capability. For some it is perfectly OK as long as it meets mission.
The other big question in my mind is whether the organization(s) you will be surveying for have published standards for aerial photogrammetry/survey. E.g. Some Dept of Transportation’s at the state level in the US will have a published standard that may require sensors are calibrated at a lab to work on a DoT contract. Might be the same when it comes to other infrastructure projects. I am NOT an expert in this field. I just build the things. Rarely get to use them. It’s just something I am watching very closely as this is relatively young tech in a new market and there is a lot of hype still.
Overall, the tech exists and it’s getting better every day thanks to people here on this forum and companies like Emlid pushing L1 RTK capabilities. But there are still some integration hurdles and regulatory issues that are open as far as I am concerned. IMO, being an early adopter is only fun if you have patience and a twisted sense of humor.