Hello,
I am doing something similar to this and I noticed that all my altitude values are negative, upper and lower bounds of [-46.58488, -12.0381012]. The .xyz file for the project is [7.410^5, 3.73910^6, 1.0]. I did not select a specific altitude setting when starting the project but let the software auto select.
My images were taken using DJI drone, which seems to have some issues when importing altitudes to pix4d (Altitude - #2 by Julie_Pichon)?
Are adding GCPs the best option to fix this? and if I am going to add GCPs what is the best altitude option if I am planning on relying more on GCPs for altitude alignment?
Google maps seems to be widely used to determine lat,long,alt for GCPs, are there are other/better resources for doing this?