inSar for monitoring changes in stockpiles

Two questions: (1) Is it possible to estimate volume of stockpiles wheat, coal etc using inSAR and (2) if so could this be done with S1 data as it becomes available or would I need to wait until the precise orbital corrections were available.
Thanks

The derivation of volumes (of forests, crops,…) is mostly based on Interferometric Polarimetry. Sentinel-1 has good interferometric capabilities, but is limited by its two polarizations (VV/VH).
You can have a look at PolSARpro, especially the tutorials which guide you though a number of use cases:

But I don’t know if they also work with dual-pol data.

Thank you very much for this help and greatly appreciated. I tried SLC using VV and about a third of the stock pile had coherence > 0.5. What would be the smallest coherence acceptable in your opinion?
Thanks again!

I really can’t tell in general, sorry.

Are you aware of any published research that analyses coherence and accuracy/reliability of line-of sight displacement?
Thanks

I’m sorry, I thought you wanted to estimate volumes? I don’t see the link to displacement.

Sorry, I was not clear. I want to estimate change in volume of stockpile. I would use kriging or some other spatial modeling technique to interpolate missing areas where coherence is < 0.5.

The change in volume is probably not a coherenc process and I am not sure if you can measure that with InSAR at all. It could work if the backscatter characteristics of the surface remain the same and the change is only gradually.

My understanding is that if the coherence for a specific pixel is high (e.g. 0.9) then the displacement value is accurate. I am assuming that two SLC separated by about a week are used for the analysis. If this is the case then I assume that all pixels on the stockpile with similarly high coherence will have accurate displacement values. Each of these pixels would have a volume due to change associated with it. Interpolating displacements for pixels in missing areas and summing volume changes for all pixels in the stockpile would give an estimate of net change in volume of the stockpile. Perhaps I am missing something fundamental because of my limited understanding of inSAR.

Forgot to add… I am not interested in absolute change in volume because displacement is line-of-sight but rather an index of change in volume.

your assumptions are correct. Maybe I have falsely interpreted/translated the word “stockpile”. Do you have an example (link or image) and what kind of volume change you expect?

That is a relief to hear I am on the right track. Based on our discussion I will follow through with the example I am testing to the final image output that shows “indicative” volume change for the stockpile with missing areas filled in using kriging. I am not sure how large the volume change might be until I complete the test case. When you say link I assume it is a link to a (e.g.) Google drive tif?
Thanks again - much appreciated.

no simply an image or description of a stockpile as you understand it? There are many translations for the word into my language so I’m not even sure we talk about the same thing :grin: