Low Horizontal accuracy while vertical accuracy is very good

[chris2018]

Hi everyone,

I am proccesing around 2 sets of 400 images taken in two different places with a dji phantom 4 pro. I followed all the steps from this post: https://www.agisoft.com/forum/index.php?topic=7851.msg37494#msg37494 and everything is good until I put all the GCPs and the horizontal accuracy is around 0,5 m ...
GCPs are very accurate, photos are clear .. no problem with that..
In the first area horizontal accuracy and vertical accuracy is very good but in the secont one is 0,5 m the horizontal one..
They are similar regarding the terrain.
Am I missing something?