Access: For:
- Images: On the Menu bar, click Project > Image Properties Editor..., on Coordinate System, click Edit...
- GCPs: On the Menu bar, click Project > GCP/MTP Manager..., on GCP Coordinate System, click on Edit...
- Outputs:
- On the Menu bar, click Project > Select Output Coordinate System...
- When creating a new project, after defining the Processing Options Template, the Select Output Coordinate System window is displayed.
Important: The output coordinate system does not need to be the same as the images' coordinate system or as the GCPs' coordinate system. It is recommended, though, that the output coordinate system is the same as the GCPs' coordinate system.
There are 2 sections:
- Selected Coordinate System: Section that displays the currently selected coordinate system.
- Coordinate System Definition: Section that allows to select the coordinate system.
And 3 buttons:
- OK: Confirms and applies the changes.
- Cancel: Does not save the changes and exits the pop-up.
- Help: Opens the Pix4Dmapper help.
This section displays the currently selected coordinate system:
- Datum: Represents the selected datum.
- Coordinate System: Represents the selected 2D coordinate system.
Based on the selected datum and coordinate system the following icons appear:
-
When the selected coordinate system is WGS 84.
-
When the selected coordinate system is any Coordinate System other than WGS 84.
Note: The default Selected Coordinate System is:
- For the images: WGS84 (egm96). If the images are captured with a senseFly drone, the default Selected Coordinate System is WGS 84 (Geoid HeightAbove WGS 84 Ellipsoid=0).
- For the GCPs: The coordinate system that is selected when creating a new project under the Output / GCP Coordinate System section: Step 2. Creating a Project.
- For the Outputs:
- Arbitrary: if the project has neither image geolocation nor GCPs.
- The corresponding UTM zone: if the project has image geolocation.
- The coordinate system that is selected for the GCPs: if the project has GCPs.
There are the following options:
- Unit: It is used to set the unit of the coordinate system. The unit can be meter (m) or international foot (ft).
- Arbitrary Coordinate System [unit]: It is used for coordinate systems that the origin, the scale and the orientation are defined by the user.
- Auto detected (only for the Output Coordinate System): Based on the coordinates of the images and the selected unit, Pix4Dmapper auto detects a coordinate system. If the project does not have image geolocation, this option is not available.
- Known Coordinate System [unit]: It is used to select a known coordinate system. The search text box allows to find the coordinate system in auto-complete mode from Pix4Dmapper's database.
- Advanced Options: By enabling this check box, depending the selected coordinate system (Image, GCP or Output), some buttons or sections are displayed, for:
- Arbitrary Coordinate System
- Auto detected
- Known Coordinate System
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Access: This section is displayed for Auto detected and Known Coordinate System when the Advanced Options are enabled.
It defines the vertical coordinate system. There are the following options:
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| From .prj |
|---|
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Access: This button is displayed for Known Coordinate System when the Advanced Options are enabled.
It is used to define the coordinate system. Note:
Opens the Import .prj File pop-up, with the following options:
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| From EPSG |
|---|
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Access: This button is displayed for Known Coordinate System when the Advanced Options are enabled.
The EPSG Geodetic Parameter Dataset is a widely used database of Earth Ellipsoids, geodetic datums, geographic and projected coordinate systems, units of measurements, etc. It is used to select a known coordinate system from an EPSG code. Opens the Coordinate System pop-up: On the Choose EPSG Number section, by clicking on the arrow, a drop-down list appears that allows to select among different EPSG codes. There are 3 buttons:
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Dear Sir and Madam
I have a Problem.
When I import my Images from my DJI drone I usually choose WGS84 coordinate system and Output Coord. System CH1903+/LV95.
But my Images are always around 1km south on the map.
Which Image Coord. System do I have to choose?
Can I delete unused images in the project or only deactivade it?
Thank you.
Best regards
Chris
Hi Christoph,
Can you tell me what drone configuration do you have (drone + camera + mobile device)?
As for now, you can only disable the unnecessary images. If you deactivated the images after you processed step 1, please remember to Reoptimize your project. Read more Difference between "Reoptimize" and "Rematch and Optimize".
Best regards
I am using right now a DJI Mavic Air with a Galaxy Note 8.
Thank you
Hello Christoph,
The DJI Mavic Air writes only approximate coordinates for image geolocation and we recommend using Pix4Dcapture and synchronize images with the mobile device in order to get more precise coordinates.
In Pix4Dcapture, we incorporated precise image geolocation in the p4d file generated when downloading the images to the device. If you process your images with the .p4d file, they will have the right geolocation.
More info about .p4d file generation here and how to transfer and process images after a mission here.
If you do not use Pix4Dcapture, going through the workaround 2 of the official comment of our technical support on our community should also solve this geolocation issue.
Best,
Hello
Thank you.
Many times I don't get a such a file. It doesn't even show me the caputred picutres in the App.
Sometimes it works and it starts synchronizing after the mission, then I get this file.
I will try soon.
Is there any possibility to set some markers and lines in the Desktop software , same like in the cloud?
Another thing I would like to do is to stitch some picutres togheter, for example to make one high resolution picture of one side of a building. It should have the same quality like the captured pictures. Would that be possible?
Thank you very much.
Christoph
Hi Christoph,
Thank you for your questions.
As a reminder, this space is dedicated to give feedback about the articles themselves. For example, we will be glad to get your feedback if, from your perspective, you are noticing wrong, missing, outdated or unclear information. Your questions are not really related to the above article and then I would suggest you write on our community or to contact us via our support website.
1) About the possibility to measure distances, area or volume with Pix4Dmapper, I would suggest you have a look at this article.
2) I am not really clear with your project here. If my understanding is correct you would like to do two separate acquisitions and then merge them into one single project. If so I would suggest you read this article. Although we recommend merging separate projects, you can also process one single project even if two cameras were used, it will be recognized from the EXIF files.
Best,
I have made the unfortunate mistake of capturing my GCPs in WGS84 but need my outputs in OSGB36
Is this possible? It seems to set the GCP datum as the same as the output and I was wondering if these are tied or if Pix4D has a conversion algorithm
Hi Harry,
The output coordinate system does not need to be the same as the images' coordinate system or as the GCPs' coordinate system. It is recommended, though, that the output coordinate system is the same as the GCPs' coordinate system.
How-to-select-change-the-Image-GCP-Output-Coordinate-System!
Best,
I have two groups of images from different "input" coordinate systems.
Can Pix 4D deal with such groups in the same project?
Hi Daniel,
No, all images have to be at the same coordinate system. Υou should convert the coordinates of one of the groups.
I hope it helps :)
How can we select the output coordinate system to be an un-projected WGS84? I do not want the UTM projection. I want the exact same Output that is shown on the Input (see picture).
I need this because I want to upload the Pix generated generated DSM into the P4 RTK controller in order to utilize the terrain awareness function. If I upload the UTM DSM it is vertically off by 110m.
Hi Tylor,
As mentioned in the Output coordinate system in geographic coordinates community post, Pix4Dmapper can only export outputs in a projected coordinate system.
@Tylor, I could not find any official DJI documentation about the supported formats for DJI terrain awareness feature. Do you happen to have it? Is there any information on supported import formats?
The DSM offset that you get after importing the Pix4D generated DSM could also be related to wrongly selected output vertical coordinate systems. What is the vertical system that you select in Pix4D for the output coordinate system?
Best,
I've attached a document for terrain awareness I received directly from DJI support.
https://drive.google.com/file/d/1upn3aB-lER5_V28gFRfQjXIM22BU6d7b/view?usp=sharing
I have tried several times following the instructions exactly however whenever we take flight with the P4 RTK we are consistently 110m higher than what we should be. For example if I set the flight height in the controller to 50m it will always go to 160m.
Also below is the text from an email I received from DJI support in the same conversation:
----------
Regarding your issue:
First, ensure that the coordinate system used by the test point is the same as that used by Phantom 4 RTK for composing (if more than three image control points are set, use the coordinate system of the three image control points; if no image control point is set, use the image coordinate system by default). Please unify the output and input coordinates to the same coordinate system under the premise of no image control point. Please pay attention to the projection belt type and choose a certain central meridian.
Please compare accuracy using the same coordinate system. That is to say, WGS84, C2000, 80 or 54 coordinate system cannot be used together for accuracy comparison.
In addition, the local CORS stations of the provinces/municipalities/Autonomous regions cannot be mixed with WGS84 or CGCS2000. Ensure that when the image control points are less than 3, the coordinate system used by the aircraft and the test point, or used for mapping are the same.
What’s more, if it is a systematic deviation (all test points are pointing in exactly the same direction), it is very likely that the problem is caused by inconsistency of coordinate systems in previous operations.
----------
As far as your last question I have tried running in WGS84, but obviously it projects to UTM. We are in zone 11. I have also tried running in arbitrary.
Hi Tylor,
somehow this post slipped through the cracks, apologies for the late reply.
The offset of 110m could be caused by the geoid offset. What is the vertical coordinate system of your outputs?
If you used a geoid model that is not supported in Pix4Dmapper or if you used GCPs that shifted the whole model, then this could be causing the offset.
One thing you could try it to set the Geoid Height above WGS 84 to 110m (now it is set to 0) for the output coordinate system and process the project again.
Let me know how it goes,
Hello,
From this page:
Can someone explain why the default datum for imagery is set to the egm96 geoid? I've never worked with drone data where the georeferencing uses this vertical datum, and it would suit my company's applications much better if the default was always set to Geoid HeightAbove WGS 84 Ellipsoid=0, as we have to change it every time we process a project.
If this is an oversight then can I request the default be changed to Geoid HeightAbove WGS 84 Ellipsoid=0?
Similarly, WGS84/UTM zones as an output system is no good for us in Australia, as it is not a 'static' coordinate system, so no serious professional GIS company will accept it.
Primarily I would like to be able to set my own defaults for image, GCP and output coordinate systems since we never use the default systems in Pix4D. Having to change them for every project is just annoying and presents an unnecessary source of potential human error in generating products to a correct standard.
Regards,
Rory
Hi Rory,
Thank you for additional details to your feature request Community post.
As I mentioned earlier, I'm going to discuss your idea with our teams.
Regards
Bonjour
Je viens d'acquérir un Phantom 4 RTK connecté à un réseau local GPS à La Réunion et après plusieurs essais je m'aperçois que les altitudes sont supérieures de plus de 3 m par rapport à des points de repères connus. Il en est de même sur un projet calculer sur le PIX4DCLOUD . J'ai essayé les différentes configurations de projection y compris les MSL et l'écart reste important. ( la plus faible est celle EGM 2008 avec 80 cm d'écart).
Comment corriger cet écart, les géomètres qui utilisent ce même réseau avec du matériel LEICA arrive à une correction optimale. Ils utilisent un ficher de correction transis par l'IGN (ficher RAR07_bl.GEM).
Merci de votre retour.
Stéphane HENAFF Société IDEM'S
Hi Henaff,
The offset that you get is most probably related to the fact that it is not possible to directly define the model RAR07_bl, IGN 1989 from the area of Reunion in Pix4Dmapper. At the moment, it is possible to use three geoid models (egm84, egm96. egm2008) and the ellipsoid of the selected horizontal system.
You should either provide the offset between the desired datum and the ellipsoid of the selected horizontal coordinate system or to select the option Arbitrary Coordinate System for the outputs and the GCPs and import GCPs with coordinates in the coordinate system you specified.
I hope this helps,
Merci pour cette confirmation. J'ai réglé ce problème de calage vertical en passant par un logiciel extérieur (CIRCE) de l'IGN pour effectuer la transposition de la hauteur géographique en altitude géodésique.
Le calcul différentiel entre hauteur et altitude est en suite reporté sur le système de projection verticale et le résultat est centimétrique.
Salutations
Stéphane HENAFF
Thanks for sharing the outcome, and I am glad to hear you managed to find the correct values for the Geoid Above Ellipsoid.
Feel free to share more insights if you have them.
Best,
Hi,
my images are wgs84 / Utm zone 33N and GCPs MGI Balkans zone 6 (Gauss Krugger). I want to my outputs as same as GCPs coordinate system. How to do that?
On the Menu bar, click Project > Select Output Coordinate System...
and define the coordinate system of your outputs. I hope it helps!
hello, can you help
I have a ascii file with the coordinates in the system WGS 84 bl and shift from the geoid
How can i prepare a tif file so i can load it as a new geoid into Pix4D
Pix4Dmapper cannot work with custom geoids. Currently, Pix4Dmapper lets you choose from the geoids EGM 84, EGM 96 and EGM 2008. Converting the images' coordinates or the GCPs' coordinates to other geoids has to be performed beforehand, with 3rd party tools. For more information, please visit here.