[NEWBIE QUESTION] Ortohophoto Skewed? What I'm doing wrong?

[ReginaK]

Trial + Ardupilot IMU GPS data + NEX7 on a Multirotor, very small area (less than 1Ha) the problem is that I'm getting a "skewed" distorted orthophot when I export it. Is there a way to correct it? What I'm doing wrong?

Take a look at the orthophoto and the agisoft screen

[Alexey Pasumansky]

Hello Regina,

There are several possible reasons:

- Incorrect coordinate input, in this case Z-axis in PhotoScan is not perpendicular to the ground plane. Please check the coordinate data and coorect coordinate system selected.
- Viewer problem - if orthophoto is exported in WGS84 (units - degrees) then X and Y units will not be equal. In the viewer (like GlobalMapper) you need to select proper visualization projection, or export from PhotoScan in UTM projection to have meters along X and Y axis.

[ReginaK]

Hi, thanks for the answer.

- The coordinate comes from an Ardupilot, where do I change the coordinate system? (I know where to export it in different systems, is that it?)

- Where to select proper visualization projection in the viewer?

Hello Regina,

There are several possible reasons:

- Incorrect coordinate input, in this case Z-axis in PhotoScan is not perpendicular to the ground plane. Please check the coordinate data and coorect coordinate system selected.
- Viewer problem - if orthophoto is exported in WGS84 (units - degrees) then X and Y units will not be equal. In the viewer (like GlobalMapper) you need to select proper visualization projection, or export from PhotoScan in UTM projection to have meters along X and Y axis.

[Alexey Pasumansky]

Hello Regina,

Please check that correct coordinate system is set in the Ground Control pane settings dialog.

In GlobalMapper the Projection tab of Control Center option dialog should be used to reinterpret the data to another projection.