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LAS Elevations from P4RTK

Goodday, First post here,(P4RTK, D-RTK 2 Base, MapPro v5.06xx)

Base set up over known point, P4RTK fixed solution reading correct ground elevations near base, pic for geo ref EXIF tag shows correct elevation, Flights with Terrain awareness(photo EXIFs show elev changing:), Upload DJI work flow with ground photo. M.M.E creates LAS.

Process LAS to tin surface, surface doesn't match ground elevation of the geo reference photo provided for M.M.E by varying amounts      (0.9m-1.90m) at different flight levels.

Thanks in advance!

Tyler Lee

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How are you measuring the differences? I believe the LAS file has a different projection than the DEM which is EPSG:4326.

Also the DEM has more data points so depending on how much data you did your TIN on there are bound to some small discrepancies.  

It is always high or low or a mix of the two?

Zane 0 votes
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Measured difference is from ground orthometric(RTK, EXIF matching) to LAS surface produced.(Also used a DEM built surface as a check, it matches the tin surface elevations from LAS)  Both of which are lower.

Projections from LAS&DEM look like WGS84.  

Tin surface is projected to NAD83/UTM11N.

Small variance is expected between flight levels and DEM vs LAS. All good there.

More concerned that the surface elevation isn't closer to the geo ref photo used to process.

Tyler Lee 0 votes
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