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ENVI

Color the Point Cloud

Color Point Clouds

The Color Point Cloud tool uses RGB data from a raster to colorize a LAS file of the same location. Each point of the point cloud receives the RGB value of the raster pixel that has the same location.

You can also write a script to color point clouds using ENVIColorPointCloudTask.

In the LAS format, each RGB channel is encoded as an unsigned int (between 0 and 65535). If the raster data type is byte (0-255), the data is multiplied by a factor 256 before being used to color the point cloud. If the data type is not byte, then the data is cast to unsigned int, which can produce a point cloud with poor brightness and contrast if the data is not well spread in the 0-65535 range. The recommended process for a non-byte image is to load it in ENVI; set the stretch, brightness, and contrast as appropriate; right-click the image in the Layer Manager, and select Export Layer to TIFF. This TIFF file should then be used as the input raster for coloring the point cloud.

Follow these steps:

  1. In ENVI, open the raster to use for RGB point cloud coloring.
  2. In the ENVI Toolbox, select ENVI LiDAR > Color Point Cloud. The Color Point Cloud dialog appears.
  3. Enter the .las, .laz, or ENVI LiDAR project to color in the Input Point Cloud field.
  4. Enter the raster to use for RGB point cloud coloring in the Input Raster field.

  5. In the Bands area, click on an RGB color to map it to a raster band in the Select Band dialog that appears.
  6. If the point cloud contains points that are outside of the raster footprint, select Yes to keep these points or No to remove them.
  7. If you selected Yes, select the color of the points using the Color of Points Outside Raster button.

  8. In the Bands Associated to RGB Channels area, click on an RGB color to map it to a raster band in the Select Band dialog that appears.
  9. The output point cloud file will use the same spatial reference you select.

  10. Enter a location and filename for the Output Point Cloud file (.las).
  11. Enable the Display result check box to display the colored point cloud in the ENVI LiDAR Main window when processing is complete.
  12. Click OK. Processing takes several minutes.
  13. If ENVI determines that the input point cloud does not have a coordinate system, you will be presented with options to choose an output coordinate system.



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