The M30 has this FAQ and response:
"Does the M30 series support accurate mapping?

Not supported. TheM30 series is not designed for aerial surveying. Users can plan a flight path and capture photos in the aerial FPV mode of DJI Pilot 2 App, but the model's accuracy is not guaranteed."

My friend has a new M30T, it seems well suited to mapping.  What exacltly do"not supported" and "accuracy is not guaranteed" mean?  
What would another model provide?
Thanks very much . . . . .

The M30 doesn't have a mechanical shutter, nor what DJI calls TimeSync for accurate mapping. With M30 you can do mapping but accuracy and precision are going to be very relative. You'll need many GCPs, M3E is a much better suited if you want to do mapping.

AR_AirPrecision Posted at 11-14 00:39
The M30 doesn't have a mechanical shutter, nor what DJI calls TimeSync for accurate mapping. With M30 you can do mapping but accuracy and precision are going to be very relative. You'll need many GCPs, M3E is a much better suited if you want to do mapping.

Right, thanks for that.  What do they mean by Time Sync?  Is it dealt with in the Manual?  Thanks . . . .

stellar0645 Posted at 11-14 00:55
Right, thanks for that.  What do they mean by Time Sync?  Is it dealt with in the Manual?  Thanks . . . .

We only have M300s so info is : https://dl.djicdn.com/downloads/ ... _Manual_EN_v4.0.pdf

See page 8

OK, thanks for that info.

AR_AirPrecision Posted at 11-14 00:39
The M30 doesn't have a mechanical shutter, nor what DJI calls TimeSync for accurate mapping. With M30 you can do mapping but accuracy and precision are going to be very relative. You'll need many GCPs, M3E is a much better suited if you want to do mapping.

what AR_AirPrecision said.

patiam Posted at 11-14 13:24
what AR_AirPrecision said.

Thanks for that insight.  It does make me wonder what is the role for the M30T for considerably more $?

stellar0645 Posted at 11-14 18:08
Thanks for that insight.  It does make me wonder what is the role for the M30T for considerably more $?

All weather - long duration surveillance & inspection ( my own summary )

stellar0645 Posted at 11-14 18:08
Thanks for that insight.  It does make me wonder what is the role for the M30T for considerably more $?

M30T is aimed at 1st responder/SAR/Public Safety use cases, not mapping.

Just DJI creating and dividing the market the way they wish by intentionally removing functionality from some platforms rather than making them all as capable as they could be.

patiam Posted at 11-15 11:17
M30T is aimed at 1st responder/SAR/Public Safety use cases, not mapping.

Just DJI creating and dividing the market the way they wish by intentionally removing functionality from some platforms rather than making them all as capable as they could be.

Thanks very much for those comments.  It does shed some light on the situation.  I do see videos of people using the M30T for mapping but perhaps they are not so concerned with accuracy.

Does adding a single ground level image improve the accuracy for the M30T significantly?  On our first test of my friends new drone, that image was not available and the vertical, contour information was rubbish.

Another curious item, why provide built-in RTK capability in a system that otherwise has accuracy compromises?  It appears to be a contradiction.

Thanks again, slowly getting this into focus…

stellar0645 Posted at 11-15 18:25
Thanks very much for those comments.  It does shed some light on the situation.  I do see videos of people using the M30T for mapping but perhaps they are not so concerned with accuracy.

Does adding a single ground level image improve the accuracy for the M30T significantly?  On our first test of my friends new drone, that image was not available and the vertical, contour information was rubbish.

What do you mean by rubbish about your contour? Probably needs a higher overlap, even oblique if really high level changes.

RTK is used for precise positioning of the aircraft and it adds some interference resistance when "close" to high voltage powerline or other EMF sources.

AR_AirPrecision Posted at 11-15 23:54
What do you mean by rubbish about your contour? Probably needs a higher overlap, even oblique if really high level changes.

RTK is used for precise positioning of the aircraft and it adds some interference resistance when "close" to high voltage powerline or other EMF sources.

Thanks for your comments.  The contours bore no relationship to those provided by the local government.  Yes, the overlap was not good, especially at the edges.  We are going to redo the flight, probably at a higher flight altitude and using the zoom camera with a 21 mm focal length instead of the wide camera with a 4.4 mm focal length.  The rationale is that this may reduce the radial distortion.  Is there a better way perhaps?

As DJ I advise against using this model for accurate mapping, what would be the advantage of using RTK if other parts of the equation are less than ideal (rolling shutter, lack of TimeSync and possibly other factors which they do not specify)?  They just say that "mapping is not supported" without giving any details.

Thanks again…

stellar0645 Posted at 11-16 00:58
Thanks for your comments.  The contours bore no relationship to those provided by the local government.  Yes, the overlap was not good, especially at the edges.  We are going to redo the flight, probably at a higher flight altitude and using the zoom camera with a 21 mm focal length instead of the wide camera with a 4.4 mm focal length.  The rationale is that this may reduce the radial distortion.  Is there a better way perhaps?

As DJ I advise against using this model for accurate mapping, what would be the advantage of using RTK if other parts of the equation are less than ideal (rolling shutter, lack of TimeSync and possibly other factors which they do not specify)?  They just say that "mapping is not supported" without giving any details.

Flying lower and slower is better in your case and use 80/80 overlap. The "zoom" lens is a beter option using 2x.

RTK is again the position of the aircraft, with other payload on mapping "certified" it's calibrated with the payload.We only fly M300 so I can only refer to some tests we did with Mavic 3T.

stellar0645 Posted at 11-16 00:58
Thanks for your comments.  The contours bore no relationship to those provided by the local government.  Yes, the overlap was not good, especially at the edges.  We are going to redo the flight, probably at a higher flight altitude and using the zoom camera with a 21 mm focal length instead of the wide camera with a 4.4 mm focal length.  The rationale is that this may reduce the radial distortion.  Is there a better way perhaps?

As DJ I advise against using this model for accurate mapping, what would be the advantage of using RTK if other parts of the equation are less than ideal (rolling shutter, lack of TimeSync and possibly other factors which they do not specify)?  They just say that "mapping is not supported" without giving any details.

I bought my Matrice M30 for the high quality zoom camera to make close up inspections at a distance from sensitive or dangerous objects - power lines, towers, industrial locations, etc.
It's also good for wildlife and environmental monitoring because of that.

That said, I also use mine for making 2D maps of areas that are undergoing improvements in land use purely for guidance and comparisons.
I don't get survey level quality (cm. level precision).

The typical GPS errors in my maps is around 1-1.5 meters - fine for viewing and guidance, but not for something more rigorous.

You can get around this by creating GCPs - Ground Control Points - that have an accurate GPS location,  placing targets on the ground at that location and including them in your photos. You then upload the GCPs as part of your dataset to your mapping program and it can improve your accuracy greatly.
It sounds more like your situation needs different things though.

I find flying slower and having good overlap - 80-85% really helps increase the fidelity of the final image. If you want better vertical accuracy, you will need to run multiple flights at different offset angles and gimbal angles to capture the data. 2-3 times would be a typical scenario it seems for some of the better 3D models I've seen. Flying at different heights is also important to provide more context for the programs to use.

The RTK antennas provide fine positioning accuracy for making close and repeated inspections to dangerous equipment like power plants. Having 2 antennas means that the drone can get direction headings from the GPS since the compass is often unreliable near power generation equipment and power lines.
Waypoint missions are set up and the drones are used for repeated inspections - in some cases in large industries like the oil industry, the drones can be managed remotely and fly autonomously using the DJI dock. Being able to fly to a centimeter accurate position is vital in these industries and only the Matrice models provide that.

Sorry for the long post - as a great scientist once said, I didn't have time to make it shorter LOL.

Hoarfrost Posted at 11-16 08:24
I bought my Matrice M30 for the high quality zoom camera to make close up inspections at a distance from sensitive or dangerous objects - power lines, towers, industrial locations, etc.
It's also good for wildlife and environmental monitoring because of that.

Thanks again for that information.

Hoarfrost, you mentioned using GCPs as a means of improving accuracy.  MME offers an option to include a single ground level image to help in calibrating the vertical reference for the set of images being processed.  Is that something you use?

In various posts and articles I see lots of references to using the M 30T for mapping although DJI states that it is "not supported."  Unfortunately they do not explain what this means.  It seems that with reasonable care that model can be used for non-survey grade mapping.

I see some advice to fly lower although MME advises flying 4 to 5 times higher than the highest object in the target area.  How would you advise?

We are going to be doing some more testing, Thanks again…

You can use the M30 for mapping. It will yield results as good or better than any non-RTK drone with a similar camera, especially if you use GCPs with positions recorded using another RTK GNSS unit. When DJI says "not supported" they are referring to precision, survey-grade mapping. They're just saying that despite having RTK GNSS, the M30 is not guaranteed to deliver the cm-precision of their other aircraft designed for survey-grade mapping (P4 RTK, M3E, M300/350 RTK, etc).

WRT to altitude, that should be driven by your desired GSD. Fly as high as you can to get the resolution you need (or maybe a bit lower). Slow down and increase overlap.

Go for it.

stellar0645 Posted at 11-17 23:20
Thanks again for that information.

Hoarfrost, you mentioned using GCPs as a means of improving accuracy.  MME offers an option to include a single ground level image to help in calibrating the vertical reference for the set of images being processed.  Is that something you use?

Hello, there. As said in FAQ, the Matrice 30/Matrice 30T is not used for mapping and surveying, so we can not guarantee the performance.

patiam Posted at 11-18 08:02
You can use the M30 for mapping. It will yield results as good or better than any non-RTK drone with a similar camera, especially if you use GCPs with positions recorded using another RTK GNSS unit. When DJI says "not supported" they are referring to precision, survey-grade mapping. They're just saying that despite having RTK GNSS, the M30 is not guaranteed to deliver the cm-precision of their other aircraft designed for survey-grade mapping (P4 RTK, M3E, M300/350 RTK, etc).

WRT to altitude, that should be driven by your desired GSD. Fly as high as you can to get the resolution you need (or maybe a bit lower). Slow down and increase overlap.

Hello Captain, thanks very much for that information, very helpful.

Can you suggest flight planning software that will consider the GSD?  We are using the MME point estimator but it does not recognize the M 30 T camera and I cannot find sensor specifications to allow a custom setup, particularly the pixel pitch.  Is there a workaround for this or perhaps other software?  I want to strike a balance among the GSD, flight altitude, focal length and overlap to get a reasonable 2-D product with a minimum image count.  I do not have access to the drone itself.

Thanks again, certainly appreciate your suggestions…

DJI Wanda Posted at 11-18 23:57
Hello, there. As said in FAQ, the Matrice 30/Matrice 30T is not used for mapping and surveying, so we can not guarantee the performance.

Hello Wanda, thanks for the note.  To the contrary, as we see elsewhere, the M 30 T is being used for mapping, apparently with satisfactory results, particularly with GCP's.  So, what performance level are you not able to guarantee?  It is unfortunate that the FAQ is so vague on this topic.  It simply raises doubts without adding any clarity.

Thanks very much…

stellar0645 Posted at 11-19 00:19
Hello Wanda, thanks for the note.  To the contrary, as we see elsewhere, the M 30 T is being used for mapping, apparently with satisfactory results, particularly with GCP's.  So, what performance level are you not able to guarantee?  It is unfortunate that the FAQ is so vague on this topic.  It simply raises doubts without adding any clarity.

Thanks very much…

The design for the Matice 30 series is not for the mapping. Users can choose to use it for mapping but we can not guarantee the final accuracy.   

DJI Wanda Posted at 11-19 01:35
The design for the Matice 30 series is not for the mapping. Users can choose to use it for mapping but we can not guarantee the final accuracy.

OK, thanks . . . . . .

stellar0645 Posted at 11-19 02:14
OK, thanks . . . . . .

We appreciate your understanding and support.

stellar0645 Posted at 11-19 00:10
Hello Captain, thanks very much for that information, very helpful.

Can you suggest flight planning software that will consider the GSD?  We are using the MME point estimator but it does not recognize the M 30 T camera and I cannot find sensor specifications to allow a custom setup, particularly the pixel pitch.  Is there a workaround for this or perhaps other software?  I want to strike a balance among the GSD, flight altitude, focal length and overlap to get a reasonable 2-D product with a minimum image count.  I do not have access to the drone itself.

I've never heard of MME point estimator. Any decent flight planning software used for mapping (DJI Pilot, UgCS, DroneDeploy, Esri SiteScan, Pix4D Capture, etc.) will allow you to plan based on altitude/GSD/overlap. They all have the camera model for your drone built in so that they can provide interactive numbers for all these parameters. If the software you're using doesn't do that then it's time to try something else.

stellar0645 Posted at 11-17 23:20
Thanks again for that information.

Hoarfrost, you mentioned using GCPs as a means of improving accuracy.  MME offers an option to include a single ground level image to help in calibrating the vertical reference for the set of images being processed.  Is that something you use?

It sounds like your MME program thinks a single ground level point will provide greater vertical precision. I don't really know much about mapping, but what I know about ground control points is that you need generally a minimum of 5 - one for each corner and one in the center of your mission area.
If you have different elevations, you will need to add them at different points to continue to guide the software to assemble an accurate map.
The GCPs provide accuracy closer to what you could get using RTK. Since the GCPs are set on points of the earth known accurately from surveys this data can be used to increase the accuracy of surveys taken with a drone like the M30.
Height is a different issue and is dependent on the resolution you require at the ground - how many cm/pixel is "good enough".
There are realities - if you are covering a larger area - 2 square miles or more, there will be thousands of photos with 80-85% overlap even if you're flying at 500 feet AGL. If you need greater resolution, you will need a camera with higher mpx or fly lower and slower.
The M3E has a mechanical shutter vs. the electronic shutter on the M30. There will be much more rolling shutter effects on the M30 which means you will have to fly slower. Data I've seen shows that the M3E can fly missions at twice the speed of the M30.
That said, I've been able to get good results flying at 18-20 mph at 280-300 feet AGL with shutter speeds around 1/320 sec.

patiam Posted at 11-19 09:06
I've never heard of MME point estimator. Any decent flight planning software used for mapping (DJI Pilot, UgCS, DroneDeploy, Esri SiteScan, Pix4D Capture, etc.) will allow you to plan based on altitude/GSD/overlap. They all have the camera model for your drone built in so that they can provide interactive numbers for all these parameters. If the software you're using doesn't do that then it's time to try something else.

Thanks, Captain.  Sorry, I should have been more clear.  MME is the Maps Made Easy flight planning tool which also provides a GSD and estimated cost.  I have been pleased with their processing, very economical.

I just installed Pix4D Capture Pro on my android tablet but it did not offer the M30T model.  I am not sure about the others, they probably need a paid plan.  I will check further.

The problem is, it is not my drone and it is 500 miles away; I am helping my friend to set it up from a distance.

Thanks again, will keep on trying other options…

Hoarfrost Posted at 11-19 15:14
It sounds like your MME program thinks a single ground level point will provide greater vertical precision. I don't really know much about mapping, but what I know about ground control points is that you need generally a minimum of 5 - one for each corner and one in the center of your mission area.
If you have different elevations, you will need to add them at different points to continue to guide the software to assemble an accurate map.
The GCPs provide accuracy closer to what you could get using RTK. Since the GCPs are set on points of the earth known accurately from surveys this data can be used to increase the accuracy of surveys taken with a drone like the M30.

Hoarfrost, thanks for your comments.

Yes, the Maps Made Easy processor will accept a single ground-level photo as an altitude reference, not for the image.  Probably as a workaround if real GCPs are not available.  I believe it is used to calibrate the barometric and GPS altitudes from their own elevation model.  

I know that the GCP approach is the better one and also improves the horizontal accuracy as well as all of XY and Z are, or should be, accurately surveyed.

Thanks for the comments on the shutter considerations; I note your suggestions regarding speed, altitude and shutter speed .

Thanks again for your help…