# Z-axis inverted?
**URL:** https://community.opendronemap.org/t/z-axis-inverted/26966
**Category:** General Help
**Created:** [September 28, 2026, 4:46am UTC](https://community.opendronemap.org/t/z-axis-inverted/26966 "2026-09-28T04:46:30Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@falconensis](https://community.opendronemap.org/u/falconensis)
#### Post date: [September 28, 2026, 4:46am UTC](https://community.opendronemap.org/t/z-axis-inverted/26966/1 "2026-09-28T04:46:30Z")
Hello all,
I am teaching an undergraduate class in SfM and I wanted to use the dataset found here: [GitHub - merkato/odm\_boruszyn\_kap: OpenDroneMap Boruszyn dataset · GitHub](https://github.com/merkato/odm_boruszyn_kap/tree/master)
The dataset is small enough that most students will be able to run it without a problem. However, after testing it myself it seems like the orthophoto, as well as the 3D model, are upside down.
The negative-GSD warning appears late, during report generation: [WARNING] Negative GSD estimated, this might indicate a flipped Z-axis. (the complete task output is pasted at the end of this post). I loaded the gcp\_file.txt along with the images and used only the default setting.
I will assume that the GCPs were included since the report reads, “Geographic Reference: GCP” and “GCP errors: 12.91 m.” Though the report only contains a table with 2 GCPs, 1 and 2 even though there should be 5.
Importantly, the orthophoto had already been generated before this warning, and the subsequent processing continued normally.
The browser was Safari on a MacBook Pro, Apple M2 Pro, 16GB of RAM).
Any suggestion would be appreciated. Thanks!
Mathieu
_ **Truncated Task Output** _
> **[console.txt](https://drive.google.com/file/d/1X5fsXdvpLUrNYzqFMX4DU0cH1o5e1nf_/view?usp=sharing)**
>
> Google Drive file.
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### Author:  [@falconensis](https://community.opendronemap.org/u/falconensis)
#### Post date: [September 28, 2026, 6:30pm UTC](https://community.opendronemap.org/t/z-axis-inverted/26966/2 "2026-09-28T18:30:24Z")
Hello all,
Let us not worry about this dataset and my question. I tried to recreate the GCP file but to no avail because it is difficult to know where the GCPs are located on some of the images. I just need to choose another dataset for my in-class exercise, that is all.