I have a .obj file output from OpenDroneMap. But I cannot determine if it is geo-referenced or not. How can I determine that?
Short answer is that OBJ files are not likely georeferenced.
According to Wikipedia, OBJ (aka Wavefront) files are "a simple data-format that represents 3D geometry alone". The article continues to explain that "OBJ coordinates have no units" (Source 1).
In an article about importing 3D files into ArcGIS Pro, OBJ files are also mentioned. The article specifically mentions that GeoVRML "is the only format that has a defined coordinate system". The article continues to state that most other models use local coordinate systems (XYZ center of 0, 0, 0). The article mentions ways of potentially georeferencing these other types of files (Source 2).
Source 3: https://docs.blender.org/manual/en/latest/addons/import_export/scene_obj.html (Additional information on OBJ file format)