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RTK question

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Hi Guys

New addittion to the forum as only just discovered this site, whilst searching through to find an answer to the following issue.

Our office has obtained a M210 RTk platform wit z30 zemuse camera and whilst Im a reasonably proficient pilot my knowledge of RTK is limited. A client asked us to do a job and we thought that the M210 would be a suitable platform to deploy however the client mentioned that while the M210 is RTK the camera isnt. ive used GCP with rover stations before but I presumed that an RTK system would work in conjucntion with the supplied camera. Does anyone have any knowledge that can shed light on the clients response eventually I will speak to the client but Id like to arm myself with a bit of knowledge before I do so to prevent looking stupid (be just my luck the client will be on this forum)

Thanks in advance
 
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"Do a job?????" Could you be more vague?

Sir, with all due respect, please pretend for a moment that we don't know you, your business, your client and especially this "job" you speak of.

Your clues of "GCP" tells me mapping. But it makes NO sense that the Z30 would NOT work for mapping. Pretty much ANY camera will work for mapping. Mechanical Shutter is a real preference, but not necessary.

I know the Z30 is a zoom camera, but have no idea why your client would dismiss it for mapping (assuming you're mapping). Did he give you a reason? Your client seems to think that the Z30 photos won't be geotagged with GPS data??? If so, why would he think that? It's pretty easy to snap a photo with the camera and show him the metadata.

I assume the Z30 is supported by your mapping software, yes? I assume this is something you would have checked already, yes?

D
 
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Apologies wasnt trying to be dense just got several balls in the air and trying to juggle one handed.

After much review apparently he is correct (waiting to speak to my colleague to clarify the exact details as it was him that spoke to a local surveying company). Although my logic was very much like yours in that any camera can be used for mapping but from what I can gather The z30 does not use the RTK data with the image it takes.

Yes we are mapping a river bed at low tide using GCP and they insisted on us using an RTK system so we borrowed from friendly forces a M210. Im not a surveyor but even though the surveying company we spoke to said the z30 is not compatible and we would need a X5s, I still find it hard to believe that the phantom 4 RTK (which we used on a similar task) can produce acceptable deliverables but the M210 cannot, however Im also of the mind that if your not an expert and you ask an expert for advice ignoring it is pretty dumb thing to do.

Really sorry for my initial post if it wasnt clear
 
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Apologies wasnt trying to be dense just got several balls in the air and trying to juggle one handed.
No worries.



After much review apparently he is correct (waiting to speak to my colleague to clarify the exact details as it was him that spoke to a local surveying company). Although my logic was very much like yours in that any camera can be used for mapping but from what I can gather The z30 does not use the RTK data with the image it takes.
Okay....so now that I *understand* the trepidation of your client, it still doesn't make sense to me for a couple reasons:

1) If the photos aren't being tagged with RTK metadata, where exactly are they getting their GPS metadata? Not knowing what goes on under the hood of the M210, I can only assume that the Matrice RTK uses GLONASS in ADDITION to RTK data, yes? This makes sense, as it would be an engineering faux pas to sell a drone that *requires* a ground station for simple flight. But then what does NOT make sense is that the RTK data - when available - would NOT be tagged into the photos' metadata. I mean...the entire purpose of RTK is NOT for "more stable flight." The entire purpose for RTK is for COLLECTING and STORING that data. If I'm reading you right, RTK is NORMALLY stored in the camera, but NOT in the Z30????

That said...

2) If you're using GCP's, the RTK data becomes redundant, right? I mean...while I'm sure it's nice to have more accurate GPS data tagged into each photo from the get go, you're correcting the accuracy anyway with your GCP data, and then "rendering" the final project based on the more-accurate (to 1/10th inch, if memory serves) GCP data.

As you can probably guess, aerial mapping is my bread and butter. My partner and I deliver architectural-grade maps to our clients and have for years. The real game changer was not RTK, but active GCP's that collect and store GPS data (Google "AeroPoints"). My partner is more learned when it comes to what goes under the hood of this process (he's the "survey engineer" and I'm the "drone guy"). While we're interested in RTK as a REPLACEMENT for these active GCP's in areas where getting boots on the ground is impractical, we certainly do not RELY on photo metadata to create accurate orthophotos.




Yes we are mapping a river bed at low tide using GCP and they insisted on us using an RTK system so we borrowed from friendly forces a M210.
You see, I just did a gig exactly like this. In fact, this "monitoring river levels" gig is one of our on-going gigs. I think our contract calls for 2 or 3 readings per year over the next 5 years. It's a lucrative contract, but I digress. My point is that we use GCP's and GLONASS to provide river data to a government entity.

There are five sites that we're mapping along the river. Here's one .kml sent to me by my business partner. This job was shot back in May. As you can see, we use 5 GCP's for this 42.3 acre plot of land.

1573833426785.png



This plot is 143 acres, and utilizes 6 GCP's.

1573833682613.png


My point is that we provided accurate maps withOUT RTK. So I'm not sure why your client is requiring it. If he were not using GCP's, then I'd get it. But if he's laying out GCP's, it doesn't make sense to require RTK data.






Im not a surveyor...
Me, too, neither...<;^) That's my partner's job.



...but even though the surveying company we spoke to said the z30 is not compatible and we would need a X5s, I still find it hard to believe that the phantom 4 RTK (which we used on a similar task) can produce acceptable deliverables but the M210 cannot,
Agreed. This would normally be a question that would require an answer straight from the horse's mouth. Unfortunately, the horse is DJI. And you'll NEVER get a straight and/or accurate answer from them....at least not via their chat portal.




however Im also of the mind that if your not an expert and you ask an expert for advice ignoring it is pretty dumb thing to do.
Agreed. But I'm not sure what makes this surveyor an expert on the M210 RTK....unless...he's been down this road before and simply "discovered" that the Z30 doesn't get RTK data.

Okay....I couldn't stand it. I called DJI and their "experts" confirm that the Z30 is tagged with GLONASS data only. The thing is that the RTK data IS recorded in the .exif file. When I asked about exporting the .exif RTK data to the photos, I was told (at least my understanding) that there is third-party software that allows the user to view and associate the RTK data with each photo, but no way to do a global import/export operation of this RTK data into the photo metadata. While this method might be fine for 20 photos, we're not taking 20 photos. It's not uncommon to take over 1,000 photos per job. I'm sure you're in the same boat. Interesting shortcoming.



Really sorry for my initial post if it wasnt clear
No worries. You seem like a smart guy so I assume your next query will give us a little more to work with from the get go.

Interesting topic. Please share your thoughts.

D
 
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HI There

Sorry for the delay just wanted to say thanks for the effort shown (didnt expect you to contact DJI) , at least we both know the answer and why (all adds to our knowledge). The outcome of it all is while we have a DJI 210 now to hire the camera needed would cost more than hiring a Phantom 4 RTK system and given that weve had acceptable results with that thats probably the way to go for the near future at least. Once again thanks for the effort you put into this admittedly vague post.
 
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HI There

Sorry for the delay just wanted to say thanks for the effort shown (didnt expect you to contact DJI) , at least we both know the answer and why (all adds to our knowledge). The outcome of it all is while we have a DJI 210 now to hire the camera needed would cost more than hiring a Phantom 4 RTK system and given that weve had acceptable results with that thats probably the way to go for the near future at least. Once again thanks for the effort you put into this admittedly vague post.
I'm still curious as to why your surveyor is demanding RTK photos when they're laying out GCP's. That honestly doesn't make sense to me. I would use RTK in LIEU of GCP's, but never in ADDITION to GCP's. I would be very interested to hear why your client wants both. Does the RTK data cut down on rendering time or something???

D
 

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