Elevation Histogram Scale Values

How are the Elevation Histogram Scale Values derived?

In my example, I see a low of -404.25ft and a high of 327.48ft.

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I assume this is not relative to sea-level. What does a base of zero represent?

I’ve also seen references to DTM and DSM, but I cannot find those options. I am interested in the DSM to measure the height of a forest canopy.

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The values are taken from the 3D model costructed from your drone photos. The elevation values, at least for a P4P drone, are measured using a barometer which can provide good relative elevation values but worthless absolute values. You can use the Calibrate tool in DroneDeploy to move your model up or down in Z. Pick a spot with a known elevation in your model and use this tool to move it to the correct value. After this all your elevations should be much closer to their absolute value.

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Thank you! I used the Calibrate Tool to set a known point on the map to an elevation of 0.0ft.
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Then all the elevations on the map are a relative offset to that point. That can give me consistent comparative results for future elevation maps.

I will try to obtain an an actual GPS elevation for a known point on the map and experiment with calibrating the actual elevation at that point.

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