Colorizing points with imagery

Purpose:
  • Top-down projection of RGB imagery

  • Improve visualization

  • Assign other GDAL data to points

Colorization (setup)

  • LAZ point cloud

  • GeoTIFF

Range?

  • GDAL assigns NODATA values

  • Range filter tosses them

Colorization (pipeline)

{
    "pipeline": [
        "./exercises/analysis/colorization/uncompahgre.laz",
        {
            "type": "filters.colorization",
            "raster": "./exercises/analysis/colorization/casi-2015-04-29-weekly-mosaic.tif"
        },
        {
            "type": "filters.range",
            "limits": "Red[1:]"
        },
        {
            "type": "writers.las",
            "compression": "true",
            "minor_version": "2",
            "dataformat_id": "3",
            "filename":"./exercises/analysis/colorization/uncompahgre-colored.laz"
        }
    ]
}

Colorization (command)

1
pdal pipeline ./exercises/analysis/colorization/colorize.json

Colorization (polygon)

_images/colorize-run-command.png

Colorization Filter

  • For every point

    • Query GDAL-readable raster

    • Set point attribute to band value

LAS Writer

  • Output LAZ

  • LAS 1.2

  • Point Format 3

Colorization (verify)

_images/colorize-umpaghre-colored.png