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Feedback from 3 days, 50+ flights, 7210 images captured

Hi all, we do a lot of large scale mapping with fixed-wing UAVs, and are heavy Pix4D users. We recently tried using a multi-rotor for a 20km road survey, as it needed higher resolution imagery than we could reliably get with the fixed wing. It worked, but not without some issues: here’s the feedback.

This is all using the latest Pix4DCapture under Android on Lenovo 7" tablet.


Critical missing feature: Polygon Areas

This project was a road survey, and although large sections of it were straight, and therefore suited to a simple rectangular capture area, much of it was winding curves and this was incredibly inefficient to capture with only rectangles. For example for some 500m sections I needed to fly 4 separate flights to tile it with rectangles.

The ability to add/remove vertices from the capture polygon, and also then define the flight line direction (two finger drag to rotate the flight lines would be great, plus a numerical input) would allow for much better capture in this and many other cases


Bug: camera sometimes not nadir

I experienced a number of flights where after landing I checked the photos and they were forward facing rather than down. I *think* this correlates to times where I manually took off and then switched to automated flight, but can’t be certain. Nevertheless, it would be good if the app was more actively ensuring that the camera was pointing down when mapping


Bug: "Unfortunately CTRL+DJI has stopped"

I seemed to get this about 50% of the time when uploading a mission after powering up the drone. It was reliable when moving from one mission to another while powered up the whole time, so seems related to the initiation process. I always power up the transmitter first, then the drone, then unplug+replug the USB cable. It then asks which app to use, I pick CTRL+DJI, it seems happy for a bit (i.e. I see the battery reading and other telemetry), but when I go to start/launch it dies. No major problem, just switch to CTRL+DJI app, where you then notice the connection status go from connected->disconnected->connected, and you’re good to go


Bug? Auto whitebalance is all over the place

I’m not sure how this can be a Pix4DCapture bug, but I notice that the whitebalance temperature/tint it all over the place, giving wildly purple and other coloured images when they are all taken one after the other in consistent lighting conditions. I fully appreciate this in general, but if I was to take these photos manually with the Inspire looking down, I would not get this result.

No major problem, I’ve just graded them all in Lightroom to fix, but it would be good if this could be more consistent in future, perhaps using auto whitebalance for the first photo then locking that into place for the remainder of the mapping?


Bug: app slows to a crawl with many flights in a Project

I was using the project workflow, so I can have the area KML loaded in and plan each flight in turn over the top as I went. Unfortunately after about 10 flights the app slows to a crawl, to the point of being unusable. It is fine when a flight is open, but it slows/hangs when moving between a flight and the project overview (where you see all the flights). 

I’m pretty sure this will be caused by storing previous flight image positions in an inefficient way. We’ve seen similar performance problems with other high-end commercial systems when they have tens of thousands of image dots marked, and they tend to have a ‘clear’ button to erase these and make it fast again. Alternatively, store them in a more efficient memory structure rather than what I expect is a flat list of photo positions?


Bug: flight speed setting not consistent

I noticed the flight speed would set itself back to one end or other of the slow/fast scale, despite me wanting them always flown in the middle setting. Is this stored at the project level? If so then I think you need a way of setting it at that level, rather than storing it from the first flight created in a project.


Bug: abort flight can get stuck

I had this happen a few times where I would abort the flight and the app would get stuck in a state where it is trying to tell the drone to come home, and you can’t use the app any more. I had manually taken over and landed the drone, yet the app was still in the abort process, the only available button being ‘Resume’. Quitting and re-loading the app didn’t fix it, I needed to restart the tablet to clear this


Issue: Not recognising when photos have failed

At one point I had what appeared to be a bad microSD card, in that it would start the flight and take a number of photos before then stopping. The Pix4Dcapture app showed photo dots for the entire flight, but on landing there were only for example 20 out of 120 photos taken. 

Perhaps there is another SDK hook available for verifying successful image capture, rather than assuming that each time you request a photo, one is successfully taken. Perhaps just checking that the image counter has increased by one each time, or even more naively, that the available storage space has decreased.


Feature Request: show drone heading

At the most distant points the drone is often 700m+ away, and very difficult to tell orientation visually. It would be very reassuring if the app showed the heading of the drone as a means of checking this, as you should always be vigilant and ready to take back manual control at any point. A small heading arrow pointing out the front of the drone icon would be great.


Feature Request: global setting to enable/disable image transfer

Although I’m sure it is a great feature for some people, in our workflow we would never have the drone imagery transfer to the flight control tablet, so need to cancel this dialog every time.


Feature Request: KML import for iOS app

We flew this using an Android tablet to be able to use a KML, but it would be good to have the option to use the iOS version. Every single mapping job we do starts with a KML file, I’m not sure how the app went so far along in its development missing this feature! :wink:




Anyone from Pix4D reading the forum?



1 Like

Hello Andrew,

Thank you for the detailed feedback. We really appreciate that you took the time to test our app and to send us your comments. It is very important for us to receive our users’ feedback as it helps us improving our products.

We will try to discuss your comments one by one:

Critical missing feature: Polygon Areas

We are aware that polygonal missions is a feature that many users would be interested in. It is one of our top priorities and our developers are working on implementing it. We believe that it will be part of the app in the coming months. In the meantime you can use many small grid missions to better achieve the shape of the area you would like to reconstruct, as you already did as far as we understand. For more information about how to map a polygonal shape area with the current version of the app you can take a look here:

Bug: camera sometimes not nadir

Were all the images facing forward in the flights you had this issue? Or did you have some images facing down and others forward?

Please make sure to confirm before every mission that the camera angle is correctly set. Otherwise the settings of the previous mission are maintained.

Bug: "Unfortunately CTRL+DJI has stopped"

Can you please confirm that you are using the latest CTRL+DJI version together with the latest app version?

Bug? Auto whitebalance is all over the place

We are aware of white balance (WB) issues with DJI cameras reported by some users. In the same dataset, images can appear hotter or colder with different shades, depending on the temperature of the scene. The WB parameter allows to compensate temperatures so that the color of the image is as close as possible to neutral which corresponds to sunlight at noon outdoor. At the moment, the white balance is set to automatic when flying an autopilot mission with our app. For each image the temperature is adjusted by an algorithm that optimizes the colors. A WB setting was already implemented on iOS (Auto, Sunny, Cloud) but not on Android. 

The problem is that in very rare cases, the DJI camera does not handle correctly the Auto WB and even the Sunny or Cloud iOS options might not be sufficient to ensure homogeneous temperature among the image set. However, it does not affect the reconstruction in Pix4D desktop but it can affect the visual aspect of the orthomosaic and the colors of the points in the rayCloud. 

The issue usually arises when the mapped area is particularly hot like earth or desert, meaning the colors are warmer than usually and with little contrast (few cool shades). Also changing light conditions because of clouds for instance, is difficult to handle by the camera. The best is to fly at noon with a sunny weather to ensure stable and constant lightning. Ideally we would like DJI to add a tool to their SDKs that allows to set the correct color temperature to all images from the same flight. 

Bug: app slows to a crawl with many flights in a Project

Do you have this issue after you perform the flights? Do you have enough storage space on your device?

Please also make sure that no other app is running on the background.

Bug: flight speed setting not consistent

The flight speed can be adjusted for every mission of the project using the slider from slow to fast. When a new mission is added the speed is by default set to the maximum value. 

Bug: abort flight can get stuck

Did it happen many times? Does the drone respond when clicking the Abort button? Is the connection with the drone maintained?

Issue: Not recognising when photos have failed

Only 20 out of the 120 images that were supposed to be taken are found in the SD card of the drone? 

The action of shooting a picture is based on a time lapse on Android. Every time that a picture is triggered the camera icon appears on the flight path. If for any reason the image fails to be saved in the SD card of the drone, e.g. no storage space, this will not affect the camera icon in the Mission view. 

Feature Request: show drone heading

We understand that showing the heading of the drone would be very helpful to check the direction the drones move towards and ensure that the drone is on the predefined flight path. We will pass your request to our Product team in order to examine if this can be implemented in the future versions of the app.

Feature Request: global setting to enable/disable image transfer

Synchronizing consists in generating the .p4d file and transferring the images from the drone to the mobile device. This is not required to process locally on a computer by importing the images saved on the SD card of the drone and by creating a new Pix4D project on your local machine.

If you need help regarding the different options on how to transfer the images and eventually the .p4d file to your computer for processing on your local machine with Pix4Dmapper, you can refer to this article: 

Feature Request: KML import for iOS app

This is not planned yet but we will add it to our suggestion list in order to be considered for future implementation.

Thank you again for the very interesting feedback! We hope that your overall experience with Pix4Dcapture is positive and we are looking forward to receiving future feedback from you.


1 Like

Australian UAV,

What software were you using prior to Pix4D capture? I’m having some of the same issues that you are having. I’m switching between an android tablet and an I pad to get the functionality that the other one does not have. Not having KML on IOS and not having Polygon on android is a bit daft IMO. In the field I’m looking at the KML to design my polygon.

+1 for the iOS KML import! This is a no-brainer. With the improved file management in the upcoming iOS 11, this should be even easier for users to handle.

I just can’t fathom how this I still missing.

Every mapping job is defined by a KML from the clients, we don’t just show up and guess where to map, dragging points around until they look right.

The code exists too, as it is working on the android version, just not iOS.

Pix4D: please! If the app is aimed at professional users, KML should be top priority


Australian UAV, What software are you currently using out of curiosity?

Its odd that there is no KML on IOS, when using the polygon function the drone does some funny movements, it fly’s backwards, not that its a problem. It just doesn’t look right.

We reported your need for the .kml/.kmz import in iOS. Note that we are also thinking about planning the mission beforehand on a computer which could be a good alternative in your case.

The drone is actually expected to fly backwards during polygon flight.

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Hi All,

Can we have an ETA for the polygon mission  feature in Android devices as it looks available nw for iOS ?–Android-and-iOS-Which-type-of-mission-to-choose?






Hi everyone,

I will be doing a big project, about a couple thousand hectares. Any tips so that I can do it fast and what to expect?

Thank you very much. 

@Benoit, a rough estimation would be by the end of this year.

@Roy, have a look at this article to get more information:

Keep in mind that you will need a lot of computational resources in order to process the project. Splitting the project in subproject would help. 

Also, do not forget to plan missions with enough overlap between each other and place enough GCPs.


Thank You Blaz