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We are trying to deliver a LAS file with NIR values added for each point. The NIR comes from a raster captured at the same moment as the LiDAR, and is stored as an 8bit number along with RGB in 8bit.

We have brought this into FME and managed to import the RGB and NIR values into a LAS file, though in the transfer the RGB becomes 16bit and the NIR stays at 8bit.

However, when our customer views the LAS file (I think in GlobalMapper) they do not see the NIR values, though they see the field. We tried bringing the LAS file into ArcMap and there we see RGB fields, but all values are 0 and no NIR field. Wondering if this maybe has something to do with FME's LAS attribute being called color_red, colour_green, colour_blue and ESRI's attributes being called red, green, blue.

Nonetheless we don't see the NIR field in ArcMap but we know it is there if we look at the same file in either FME (displays all properly) or GlobalMapper (shows field but with 0 values).

Ultimately the client wants a CSV so we are trying to generate one from FME for the LAS file that has all the information we know FME can see, but so far having issues there as well.

Anyone have any advice on what is needed to get NIR values into a LAS file that something other than FME can see?

PolyGeo
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user25644
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  • Linking related question: http://gis.stackexchange.com/questions/138611/assigning-rgb-values-from-geotiff-image-to-lidar-data-using-r. – Andre Silva Apr 22 '16 at 16:01
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    If you are doing anything other than visualization, projecting a 2D geometry on to a 3D geometry is a bad idea. Your spectral values will not match the corresponding point(s) in the lidar point cloud and therefore cannot be used analytically. If you want to relate the data, come up with a binning scheme for deriving metrics from the lidar data and use these bins to relate the spectral data. In this way you are then dealing with both data sharing a 2D geometry. – Jeffrey Evans Apr 22 '16 at 16:38
  • rename color_red to red in the attribute manager for the output? – Mapperz Apr 25 '16 at 17:10

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