No action required. (RTK) Image geolocation, horizontal and vertical accuracy is automatically recognized when importing the images. No action required.
(PPK) After PPK postprocessing in a third party software, accurate image geolocation can be imported using the Image geolocation file (.csv, .txt, .dat). If necessary, edit the Accuracy Vert/Horz column to define the actual accuracy values. No action required.
No action required. The optimized camera parameters for P4RTK (FC6310R_8.8_5472x3648) are already included and automatically recognized in the internal camera database.
No action required. The correct vertical coordinates system is automatically recognized and set to WGS 84 Ellipsoid.
Processing options
There is no need to change the default processing templates, e.g. 3D Maps, and the following processing options can be kept:
Can I process with the accurate geolocation pipeline?
Accurate geolocation and orientation pipeline can be used when both, image geolocation and orientation, are precise.
We recommend using it for large datasets (faster processing) and when the dataset contains homogeneous or complex visual content (forest and dense vegetation, flat terrain with agriculture fields, snow, sand, and water surfaces).
More in the FAQ on the accurate geolocation pipeline.
Is it possible to use another vertical datum besides EGM84, EGM96, EGM2008 or the ellipsoid of the selected horizontal system?
There is no direct way of selecting or importing a different vertical datum.
A workaround is to either provide the offset between the desired datum and the ellipsoid of the selected horizontal coordinate system or select the option Arbitrary Coordinate System for the outputs and the GCPs and import GCPs with coordinates in the coordinate system you specified.
More in the When to use the Geoid Height Above the Ellipsoid Function? and How to define Pix4D outputs with respect to a Geoid model articles.
Do I need to enable the linear shutter optimization?
What could cause a big offset when comparing the results with checkpoints?
The horizontal offset could be caused by the horizontal grid corrections and transformations.
In some cases, when flying fast, close to the ground or in high winds, enabling the linear shutter optimization could reduce the offset.
The vertical offset could be present due to wrongly selected vertical coordinates system or custom geoid models.
In case the optimized camera parameters are far from the initial values, e.g. focal length, we recommend using the All Prior processing option.
I would recommend using the Geoid Height Above Ellipsoid value when the heights of the results need to be based on a vertical datum that is not defined in Pix4D.
For example:
Geoid Height Above Ellipsoid = 0 [units], when using the EGM84, EGM96, EGM2008 geoid models (all 3 are already defined in Pix4D) or the automatically detected ellipsoidal models (by default defined in the coordinate system description).
Geoid Height Above Ellipsoid = x [units], when using a geoid model that is not defined in Pix4D, for example, GEOID12B (US), OSGM15 (GB).
In the second case, you should know the shift/offset between the current vertical coordinate system and the target coordinate system. This shift can be added in the Geoid Height Above Ellipsoid option.
Hi, I have my own geoid for my country in TIF like original 3 geoids implemented into Pix4D mapper. Can you change TIF file like this to fit into Pix4D? This would help in my work combined wit ph4 RTK.
At the moment it is not possible to import a geoid model (.TIFF) and I would recommend using the offset in order to shift the results (Geoid Height Above Ellipsoid option).
I forwarded the suggestion for importing the geoid models to the product managers in order to consider implementing it in the future releases.
I have used your method with success to shift my ellipsoid heights to the NAVD88 vertical datum using Geoid12B by entering a geoid height in " Geoid Height Above WGS 84 Ellipsoid" box that best defines my project area.
I have done it by adding the geoid height to the image coordinate system upon image import and then outputting in my desired coordinate system with a 0 value entered for geoid height. This method allows me to input my GCP’s in NAVD88 orthometric heights.
I have also done it by leaving the image coordinate system geoid height at 0 and then adding the geoid height to the output coordinate system. Using this method I have to bring in my GCP’s in WGS84 ellipsoid heights.
I see both ways work, but does Pix4d recommend one method over the other?
I ultimately think the best method will be to leave everything in ellipsoid heights and then use NOAA’s VDatum to apply Geoid12B to the .las file and shift the data to NAVD88. I think this would be more accurate for a large project area.
Blaž, I’ve been using the P4 RTK since release date back in November. I’ve been having a hard time to get this to work because I always get different suggestions from Pix4D. My biggest problem is the elevation in the datasets, is always off by a couple of feet. I was told to use Arbitrary because the elevation was corrected with the photo thru Propeller PPK processing, this is close but when you hover over the GCP the elevation is higher all the time. Its been almost 6 months since the release of the Phantom4 RTK and Pix4D still don’t have a streamlined process for the data coming from this drone. Please, I need help with this process. I’m using NAD83 Florida East (NAVD88 height)
@Andrew, as you mentioned, both options will work and the results should be the same if the same Geoid Height Above Ellipsoid value is used.
Using external tools as NOAA’s VDatum would indeed be better for larger projects where the geoid separation cannot be represented with a single value.
A good workaround would also be to transform the heights of the images to orthometric before processing the dataset Pix4Dmapper. This can be done with a custom file that contains the transformed coordinates and using the “From File…” option in the Image Properties Editor.
A more detailed workflow on how to import custom values is available in the Phantom 4 RTK - PPK processing community post.
Can you please comment on best practices in Pix4D to address this issue? Should we be including oblique imagery, or is there some other processing workflow in Pix4D that we should implement, such as creating a custom camera calibration?
I’m happy to provide datasets, Quality Reports, etc. if you would like to have a look.
As @Lukasz suggested, Pix4D should allow import of a Geoid Height raster or text file rather than requiring a single value. These products are available from NGS or can be created easily by the user, and can account for the variation in Geoid height over the study area.
I understand the method you described using “From file…” to alter image altitudes, but this is an inefficient workaround compared to just being able to point at a file representing the Geoid height spatially.
I am okay using WGS84 as an input coordinate system.
But will it effect my results if I want OSGB as an output coordinate system?
My results seem to be horizontally offset!
Hello,
You have already opened the support ticket so we will deal with the issue there. If there is anything new that is helpful for others, I will share it on this post. Your’s output coordinate system should not be the reason for the issue.
Be careful with Arbitrary. It actually puts your project in International ft instead of US Survey ft. You won’t see much of an issue on smaller projects, but anything of size you will see errors.
I am having some difficulty with the Pix4D processing results using data from my Phantom 4 RTK. I set the parameters to reflect the recommendations in your original post, however the modeled elevation data is incorrect. Elevation seems to be relative to a point on the model instead of an absolute elevation. The model seems to have selected a high point in the data and set that location to 0 elevation.
Have you encountered this issue before? Might you have any insights into correcting the problem?
Hi, when i import images taken from a P4RTK it read the location but accuracy is 5m/10m regardless of i click on “Standar”, “low” or “custom” geolocation accuracy.
In fact is not reading Omega / phi / Kappa values.
Does anyone know how make it read these data and not entering by hand one by one ???
I know the files has this values which i paste here:
xmp:ModifyDate=“2020-02-01”
xmp:CreateDate=“2020-02-01”
tiff:Make=“DJI”
tiff:Model=“FC6310R”
dc:format=“image/jpg”
drone-dji:AbsoluteAltitude=“+182.38”
drone-dji:RelativeAltitude=“+114.01”
drone-dji:GpsLatitude=“-31.78085196”
drone-dji:GpsLongtitude=“-60.43350743”
drone-dji:GimbalRollDegree=“+0.00”
drone-dji:GimbalYawDegree=“-80.60”
drone-dji:GimbalPitchDegree=“-90.00”
drone-dji:FlightRollDegree=“+0.10”
drone-dji:FlightYawDegree=“-80.30”
drone-dji:FlightPitchDegree=“-8.60”
drone-dji:FlightXSpeed=“+1.40”
drone-dji:FlightYSpeed=“-8.80”
drone-dji:FlightZSpeed=“+0.00”
drone-dji:CamReverse=“0”
drone-dji:GimbalReverse=“0”
drone-dji:SelfData=“Undefined”
drone-dji:CalibratedFocalLength=“3666.666504”
drone-dji:CalibratedOpticalCenterX=“2736.000000”
drone-dji:CalibratedOpticalCenterY=“1824.000000”
drone-dji:RtkFlag=“50”
drone-dji:RtkStdLon=“0.01246”
drone-dji:RtkStdLat=“0.01099”
drone-dji:RtkStdHgt=“0.02442”
drone-dji:DewarpData=" 2019-07-22;3691.040000000000,3684.350000000000,-4.670000000000,-14.490000000000,-0.266666000000,0.121035000000,0.000135811000,-0.000305676000,-0.047761600000"
drone-dji:DewarpFlag=“0”
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