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Elevation Difference in the DSM & DTM

Hi Pix4D Community

I have developed the DSM and DTM but the Highest elevations differ by 3m. The DSM elevation range is 342.7 - 417.992 and the DTM elevation range is 342.7 - 414.865. Both models have the same elevation and the GSD is 3.03.

What could be the reason for this and how can I solve it?

Kind Regards

Hi Mogapi,

Were the DSM and DTM generated within the same Pix4Dmapper project? Please note that only the Ground and Road Surface land cover classes are preserved in the DTM. The other point cloud classes are being smoothed using a spatial interpolator. Long story short, it is expected to have different elevation ranges in the DSM and DTM.

Hopefully this answers your question.

Cheers,
Teodora

Thanks Teodora

The models were generated from the same project. So there is no solution?

Hello again,

No, there is no solution. In terms of elevation values, a DSM differs from a DTM. It is like comparing apples with oranges. Think of smoothing as an algorithm that “cuts out” some elevations that might have been the maximum values in the DSM. Once removing these maximum values, you obtain a DTM where the new elevation range will have different minimum and maximum values.
I hope it makes sense.

Cheers,
Teodora

Makes sense

Thnx Teodora.

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