Export Orthophoto and DEM

[agi_user]

I am trying to export a DEM and orthophoto as a tiff file for use in ArcGIS Pro.

I had tried using geographic coordinate system WGS 84 to build DEM, but I then get an error "unsupported datum transformation" when I try to build the orthophoto.

I switched the reference settings to local coordinates, checked marker coordinate as WGS 84, and redid the DEM. It allowed me to build orthophoto with 1 mm size pixel with the DEM as a source. However, when I import the DEM and orthophoto from tiff file into ArcGIS Pro, the scale is completely off. I can georeference the  model in ArcGIS with the ground control point and lat/long coordinate, but instead of having 1 mm pixel, it is tens of thousand of meters per pixel. How can I fix this issue with the pixel size so it is at the right scale in ArcGIS? Is this an issue with the Agisoft workflow, export, or ArcGIS?

[Alexey Pasumansky]

Hello agi_user,

You cannot mix Local Coordinates with the geographic coordinate systems in the same system.

If you want to get the result in WGS84, then use this system as a main reference in the settings and load the coordinates in this system to the reference points. Then re-build DEM in geographic projection and use DEM as a source for the orthomosaic generation.

[agi_user]

Hi,

Thanks for your response. Using WGS 84 as the main reference system is the first thing I tried. But as in my previous post I get the error "unsupported datum transformation" when I try to build the orthophoto with DEM as source.

How can I work around this error? Thanks in advance.

[Alexey Pasumansky]

Hello agi_user,

Can you please specify the following:

- which coordinate system is selected for the chunk in the Reference pane settings dialog (if individual systems are selected for cameras/markers, please also name them),
- which reference data is used: coordinates of the camera locations, coordinates of the GCPs (markers) or both?
- if markers are used - do they have the projections on at least two aligned cameras?
- if cameras are used - are there at least three cameras that have coordinate information input to the Reference pane?
- have you pressed Update button on the Reference pane after alignment in case the coordinate information has been loaded after the alignment operation?
- which source you are using for DEM and Orthomosaic generation,
- if you are using imported DEM, then in which coordinate system it is referenced? Does this system have EPSG code or ToWGS84 parameters?
- which coordinate system you are selecting in Build DEM / Build Orthomosaic dialog?

[agi_user]

- which coordinate system is selected for the chunk in the Reference pane settings dialog (if individual systems are selected for cameras/markers, please also name them),

Coordinate system is WGS84 and marker reference is checked as WGS84

- which reference data is used: coordinates of the camera locations, coordinates of the GCPs (markers) or both?

Markers only

- if markers are used - do they have the projections on at least two aligned cameras?

I only have coordinates for 1 marker

- if cameras are used - are there at least three cameras that have coordinate information input to the Reference pane?

Camera coordinates are not used

- have you pressed Update button on the Reference pane after alignment in case the coordinate information has been loaded after the alignment operation?

Yes

- which source you are using for DEM and Orthomosaic generation,

I use the dense cloud to build the DEM, and then try to use DEM as source for the orthomosaic.

- if you are using imported DEM, then in which coordinate system it is referenced? Does this system have EPSG code or ToWGS84 parameters?

I don't use an imported DEM

- which coordinate system you are selecting in Build DEM / Build Orthomosaic dialog?

When I run the build DEM, I choose Planar projection, and use markers as projection plane. If I try to run it is as geographic the pixel size is crazy high (millions) and processing  goes no where.

For the build orthomosaic the coordinate system is greyed out but is set at WGS 84. When I try to run this step it gives error "unsupported datum transformation"

[Alexey Pasumansky]

Hello agi_user,

The model can be georeferenced if there are at least three reference points (checked on instances of aligned cameras or markers in the Reference pane). With the single marker you cannot georeference the model as it doesn't allow to define neither scale nor orientation of the model in space.

So it seems that in your case you have the model that is not georeferenced (not enough referencing data) and the error indicates that such model cannot be saved in geographic coordinates, as they are undefined.