Hello, I am posting this after several days of methodical, sequentlal testing while capturing screenshots at points in time. Ideally, representatives of Pix4D will provide additional information, so that Pix4D customers can have more success when using the Pix4D Mapper (Desktop) user interface, Help pages and supporting video tutorials.
This post is primarily for someone who is attempting to use State Plane coordinates within Pix4D Mapper (Desktop) (“Pix4D”). I chose Pix4D because the licensing option was appropriate for annual work on an environmental monitoring project with a limited budget. I have a one month license of Pix4D (soon to expire). I have prior experience with a trial version of Pix4D, a trial version of Global Mapper, and Pix4D Capture for mission planning. I have studied many of the Help pages, searched the Community site, and watched tutorials. Before this last round of using Pix4D, I had created many Pix4D Projects.
Unfortunately I found several ways to be unsuccessful with Pix4D. If you are having difficulty, maybe the following sequence of screenshots and comments will help in your troubleshooting and interactions with representatives of Pix4D and other software suppliers or online services. Clues to some success are in screenshots 1 through 11 below.
Background: I commercially operate several different UAV systems covering a wide range of field applications. The most recent acquisition is an Inspire 2 with the related kit from Klau Geomatics, and I have seen <3cm results in X, Y and Z axes after PPK with correction with data from a local CORS in the Washington State Reference Network. Therefore I am not using Ground Control Points during Pix4D processing. However I have Ground Check Points for comparison to Pix4D model data.
Screenshot 1 (below): Up until a few days ago, none of my Pix4D models were successful when I attempted to use State Plane coordinates.
However by the date and time of screenshot 11…. I had discovered settings that resulted in a model with correct X_Y_Z coordinates in meters.
Let’s start with Screenshot 1, below, where you can see the top of the images table. Note the Pix4D default values in the Vertical and Horizontal Accuracy columns. With default values the process is over 7 hours on my Lenovo P70. I could have changed the values to 3 cm (or to 0.09 ft) to match the values on my PPK geo-tagged images, however I did not require that level of accuracy in this model.
Screenshot 2: Note the selection of ‘ft’ and ‘Arbitrary’ in the context of this popup.
Screenshot 3: The model has been generated. Note the elevation value of -57.37 feet for the marker on the large rock.
Screenshot 4: The value of a point on the sand below the rock wall is -68.44. Checking other points in this model, the elevations are increasingly negative starting from some camera sensor altitude above the ground.
Screenshot 5: Note the change from feet to meters, leaving this ‘Arbitrary…’ selected. The resulting model continued to have the incorrect negative elevation values.
Before clicking OK, I used ‘Save Project as…’ to save the previous Project with a different name (‘Oct.11’).
Screenshot 7: After checking ‘Advanced…’, note the selection of this ‘Arbitrary…’.
Screenshot 8: I saw the Warning popup, then clicked OK.
Screenshot 9: Decided to ‘reoptimize’. This screenshot is after clicking to reoptimize. Conveniently, the two red ‘cameras’ related to the images of my two ground check point markers were ignored later when Orthomosaic views were generated.
Screenshot 10: Note the Warning.
Screenshot 11: Note the Warnings about two skipped images. Not a problem. I had left those two image files in the larger collection. Good to know that Pix4D skipped those files. Note the Warning about Ortho Gain.
After processing was complete, were the X_Y_Z values correct in the Orthomosaic view? Yes! Success! However units are in meters, not in feet.
You can stop reading here, if you are content with models/views in meters.
However I wanted a way to display feet rather than meters, and to use State Plane settings.
(As of the date of this original post, I had no success with using feet or State Plane. Maybe by posting this, someone will suggest a way.)
Screenshot 12: Now I changed Units from meters to feet. See the values for ‘Selected…’, ‘Known…’, and ‘Arbitrary…’. I am not positive, however I *think* that the values in ‘Selected…’ and ‘Known…’ were populated immediately after I selected ‘ft’ for Units.
Screenshot 13: The screenshot below is just prior to selecting a value from the EPSG list. (In past experiments with Pix4D, #2855 was missing in the drop-down list for EPSG. This time, with this Project, I found and selected #2855. Curious that 2855 was not visible in previous Projects, however it was this time. Really, I looked very carefully during past Projects but failed to find ‘2855’.)
Screenshot 14: I found the message below to be ambiguous. If I knew the intent of the author, I might suggest different text. I clicked Yes.
Screenshot 15: Warning before reoptimizing.
Screenshot 16: Note the Warning popup. What is not visible is a rotating symbol (like: something is being processed) that continued for many minutes. I opened Task Manager to see if there was substantial activity. After a few minutes I gave up and clicked OK, which caused processing to continue.
Screenshot 17: Waiting for Tie Points.
Screenshot 18: Just prior to choosing Reoptimize first (as prompted), before Steps 2 and 3.
Screenshot 19: Reoptimizing progressing.
Screenshot 20: Step 2 started.
Screenshot 21: Process failure. Should I start all three Steps, again? I decided Yes.
Screenshot 22: Processing all three steps. (Just before grabbing this screenshot, Steps 2 and 3 were in green text.)
Screenshot 23: Warning about GDAL.
Screenshot 24: Seeing negative elevations. I changed from ‘Known…’ to ‘Arbitrary…’.
Screenshot 25: Shall I wait, or click OK? At this point I gave up trying to generate models in feet or with State Plane.