Georeferencing

Purpose:

  • Transform airborne or mobile LiDAR points into usable point clouds.

Components

  • LiDAR point stream
    • X, Y, Z

    • Timestamp

  • GNSS/IMU point stream
    • GPS X, Y, Z

    • IMU roll, pitch, yaw

  • Lever arm and boresight matrix

  • Combine with the georeferencing equation:

_images/georeferencing.png

Caveats

  • Generic georeferencing is not yet implemented in PDAL.

  • The readers.optech includes built-in georeferencing, which automatically projects data to WGS84.

Command

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pdal translate \
./exercises/georeferencing/S1C1_csd_004.csd \
./exercises/georeferencing/S1C1_csd_004.laz \
reprojection range \
--filters.reprojection.out_srs="EPSG:32614" \
--filters.range.limits="Intensity[0:500]"
  • In order to display the data easily in plas.io, we must reproject to UTM.

  • There are some spurious points close to the sensor that skew the intensity distribution. By filtering these points, we will improve the default display in plas.io.

Verify

_images/georeferencing-run-command.png

Visualize

_images/georeference-plasio.png