Altitudinal problem

Hi everyone,

I have a project which is to generate topographic maps of the ice surface on a glacier. We have taken picture with a camera on a drone and generate the model with pix4d. But the model is wrong on different coordinates, During our expedition, we have taken some DGPS points with their coordinates. I have add all of them (just like 3 or 4) to the model and it is a little corrected but not all the model is right.

My question is; if I want a real and reliable model, do I have to take more DGPS points and add them to my map? It can work? Or I have done mistake in my process ?


Thanks a lot !


First and foremost, make sure that your dataset has sufficient image overlap. In order to acquire an optimal dataset, please follow our best practice here:

Sometimes, the 3D reconstruction is not optimal because the software could not find enough keypoint matches to stitch all the images of the dataset. To improve the 3D reconstruction, please add Manual Tie Points (MTPs) and reoptimize the project after performing this step. More information can be found here:

Please mark more GCPs throughout your dataset (we recommend adding 5-8 GCPs) and ensure that they are well spread around the project. Sometimes, you can get high errors in the area near the edge of the project, but this is expected due to lower image overlap.