Volume calculation of an indoor stockpile

I am looking at estimating volume of an indoor chip pile. I am looking at flying a Phantom 3 pro over the pile and using a GCP target to scale the x and y axis. Will this work with the capture app? (probably not) What other suggestions do you have to add accuracy and ease of capture and processing?

This is a very late reply, but you can create your own local coordinate system or… 

You could also measure a few things that will be in your image and scale them in your project

 

Thanks, I am looking at measuring the distance between my GCPs to add scale.