# Hyperspectral Data Processing

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Phoenix LiDAR Systems store Headwall Nano data slightly differently than payloads from other integrators. This document explains the necessary workflow for utilizing PLS data in Headwall's software.
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### Input Data

* SBET format post-processed trajectory
  * This is required for georeferencing the Nano Hyperspectral imagery.
  * Utilize NavLab (Cloud or Embedded) or alternatively Novatel's InertialExplorer to produce an SBET .out file
* DEM
  * DEM files must have a geographic projection, such as WGS84 EPSG:4326, that matches the processed SBET datum
  * The best source for a digital elevation model is from co-acquired LiDAR data.
    * After achieving an accurate ground classified point cloud in SpatialExplorer, use the [Create Maps](https://docs.phoenixlidar.com/spatialexplorer-8-and-9/user-interface/toolbars/analytics/create/create-maps) tool to output a Geodetic Elevation raster .tif file.
  * Other DEM sources can also be used.
* Hyperspectral Imagery
  * It is highly recommended that users Reformat Headwall data in SpatialExplorer before proceeding to SpectralView

### SpectralView

* Place a copy of your project DEM raster into the "dem" folder that is located in the  Headwall software install directory
  * Similar to "C:\Headwall\dem"
* Place a copy of your SBET .out file in the same directory as your reformatted Headwall data
* Open a hyperspectral data cube in SpectraView.

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Other steps, such as Radiance and Reflectance computation, may be taken prior to orthorectification in SpectralView
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* Click the "Ortho R." tool and configure the orthorectification settings.
  * Enable "Advanced settings..."
    * Set "Time offset (ms)" to -18000 to account for GPS leap seconds
    * Check "Use post process file"
  * All other settings are sensor specific.

<figure><img src="https://content.gitbook.com/content/dEevfLZRIk38LUPwDa4V/blobs/TAQCzlpTJ3hr5WAKaO0V/Headwall_Ortho_Settings.png" alt=""><figcaption><p>Example Ortho Rectification Settings</p></figcaption></figure>

* Click "Start O.R" and ensure that the results displayed on the Preview tab look satisfactory.

<figure><img src="https://content.gitbook.com/content/dEevfLZRIk38LUPwDa4V/blobs/fCgd3LSbfGN4hTfrTJgC/SpectralView%20Preview%20Tab.PNG" alt=""><figcaption></figcaption></figure>

* Select all of the wavelengths that you would like output on the Create tab and then press "Create Cube"