Export JPG's from SD card and render it with Pix4D Mapper

Flight - Discussion and Q&A
1

Hi
Is it possible to export JPG’s from the SD card of a P3P and render them with Pix4D Mapper?

If yes:

  • Are your also storing TIF’s, as they have 4 times the resolution compared to JPG’s
  • Do you store relative or absolute heights in the EXIF data?
    Pix4D Capture (Beta) currently stores relative heights which is not really useful.
2

We store relative heights at the moment.

You have access to the images so you can do what you like with them. We’d prefer you use dronedeploy to process your imagery though.

Are you asking if we are storing tiffs on the phantoms SD card?

3

Yes, storing tiffs on the phantoms SD card would be perfect for my scenario.

About the heights. That will be an issue, as the Digital Surface Modells are not 100% usable and mixing the pictures with other sources with absolute heights, which some programs allow, is only not possible.

Also exporting the models to Google Earth will also be a challenge, as the height will not be correct, no?

4

The phantom and inspire do not have be capability to store tiffs. Only raw and JPEG.

@jeremy can probably answer more about the altitude values than me. I think up to now we haven’t had a need for the absolute values for users’ use cases. We are working more on 3d models and dems this week so I’m sure he will have some more information.

5

Hi martinhaemmerli,

Re using pix4d for processing, as @chasemgray mentioned all the images (with geotags) are on the sd card so you can download them and do any further processing you’d like with them. We actually perform all the necessary photogrammetry operations automatically in our cloud software so that you don’t need to do any further image stitching / 3D modelling, however if there’s an issue with the data we produce for you, or there are additional products you’d like to see, please let us know - we’re always looking for feedback and continually improving our software / adding new features.

Re the DSM levels, yes, unfortunately the elevation values are relative (so the ground elevation should usually center on 0m). What are you hoping to use the elevation values for? Our customers who are interested in engineering surveys (who usually need really accurate DSMs) usually provide some ground control information that allow us to correct the elevation information in the model. If you’re interested in this, we can provide more information.

You should be able to open the .kml files from the orthomosaic download in google earth just fine; I believe the 3D model might be an issue because google earth limits the mesh size you can import and our meshes are way too big.

If you let us know what you’re planning on using the DSMs and 3D models for, we can help find a solution that will work for you.

Hope that helps,

Jeremy

6

Hi Jeremy and Chasemgray
Thank you for your detailed reply.
@chasemgray you’re right, I meant raw files, which I would then transfer into tiffs before processing. My customer is interested in seeing leave structures of plants for type classification and from 30 meters, that’s not possible using jpegs. With raw files and maybe a reduced altitude of 10 to 15 meters we hope that we can achieve this.
@jeremy, about the relative height. I assumed that importing the .kml files would result in deep whole on Google Earth, but that’s not the case. It actually displayed the model perfectly right.
I’m not having a customer at the moment who needs absolute heights but I wonder how the data would need to be corrected if I ever would have such a customer.
Thank you,
Martin

7

@martinhaemmerli yup, the .kml files only use the horizontal locations to reference them on google earth. If you want to correct the DSMs for a specific map you can find elevations (and lat/lng coords) of several (maybe 5) points visible in your map and send them to us, then we can correct the map elevation for you. For an approximate referencing you can use google earth to find some landmarks (e.g. road line intersection, edge of a building, etc.), but if you want centimeter-level precision you’ll need to measure some points with RTK gps.

Hope that helps and do let us know any specifics that any future customers need / want and we can incorporate them into our development schedule.

Jeremy

8

Thanks @jeremy,
What do you think. Are you able to add raw files as an option for people to select?

9

At the moment we don’t have raw images because they are not something we use for our stitching pipeline. This isn’t too hard to let people turn on. I’ll bring it up in our planning meeting this week.

10

Thank you @chasemgray

11

And flight altitude of 10 meters? Will this be added as well?

Thanks,

Martin