Changes between Version 33 and Version 34 of Processing/LidarCalibrationProcedure


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Timestamp:
Aug 29, 2012 5:11:11 PM (7 years ago)
Author:
emca
Comment:

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  • Processing/LidarCalibrationProcedure

    v33 v34  
    7575 Check the ground_classified LAS files in LAG to make sure that the classification has worked as expected. If doing it manually, you can alter the settings used in lasground e.g. using -step, -spike. See the lasground Readme for more info. When satisfied, replace the attune created *.bin files with the ground classified ones.
    7676
    77  Note: Ground classification procedures using TerrsScan can be found [wiki:Sensors/LeicaLIDAR/MashUp#Groundclassification here].
     77 Note: Ground classification procedures using TerraScan can be found [wiki:Sensors/LeicaLIDAR/MashUp#Groundclassification here].
    7878
    79795. Tie point the data [[BR]]
     
    144144 * Run the processing on the 4 low altitude flight lines.
    145145
    146 2.Load the results into Terrascan and use the 30-40 GCPs of the calibration site.
    147  * GCPs are available [wiki:Processing/CalibSite here]
    148  * Tools -> Output Control Report
    149  * Browse -> GCP file and remove bad points (maybe an error occurred in the surveying of a certain point)
    150  * Look at the dz value, the average dz is used for the nominal range offset A1.
    151  * Save the text file.
     1462. Calculate the A1 nominal range offset. This can be done using LASTools or TerraScan.  The GCPs for Little Rissington are available [wiki:Processing/CalibSite here]
     147 * LASTools:
     148     * Copy the GCP's to the 02a_ROff_+-7Deg folder. You may need to edit this file to remove some points.
     149     * Run lascontrol.exe -i *.LAS -cp gcp_points.txt -parse xyz (you may need to edit the parse command depending on the format of the GCP's you are using)
     150     * Scan the output and remove any bad points from the gcp file and re-run
     151     * Look at the average (abs) value, this is used for the nominal range offset A1. This value should not change dramatically from season to season
     152     * Note: if there are negative values in the lascontrol output then calculate the average value yourself (lascontrol gives the average absolute value)
     153     * Save the output to a text file
     154 * TerraScan:
     155   * Load the results into TerraScan and use the 30-40 GCPs of the calibration site.
     156   * Tools -> Output Control Report
     157   * Browse -> GCP file and remove bad points (maybe an error occurred in the surveying of a certain point)
     158   * Look at the dz value, the average dz is used for the nominal range offset A1.
     159   * Save the text file.
    152160
    1531613. Preferably using data including areas of forest (little riss should do) and the BIT mode data, run Rangecardcal (from ALSPP tools menu) on all flightlines. (on ~45 degrees?).
     
    1571654. Analyse the results
    158166 * Check these results and re-run using the full FOV (~45 degrees) on the low flightlines again (remember to change output back to normal folder)
    159  * Check average dz is less than 1cm or so, and standard deviation <5cm in Terrascan control report. (also look at cross sections)
    160  * Then process the 4 high altitude flights in ALSPP and check in Terrascan (around nadir and swath edges) (looking at absolute height).
    161  * Finally load in all flights into Terrascan (within a fence if memory issues) and check them (ideally along a stream because this has a “good” profile) Can use the travel path tool in Terrascan for comparing cross sections along a path.
    162 
     167 * Check average dz is less than 1cm or so, and standard deviation <5cm using lascontrol or TerraScan control report. Save the output from this check as it is used in the Data Quality report. Note for lascontrol output you will need to calculate the average dz value.
     168 * Check the flightlines in LAG/TerraScan (also look at cross sections)
     169 * Process the 4 high altitude flights in ALSPP and check in LAG/TerraScan (around nadir and swath edges) (looking at absolute height).
     170 * Run lascontrol/TerraScan control report for the high altitude flightlines and check for reasonable values. Save the output as it is used in the Data Quality report.  Note for lascontrol output you will need to calculate the average dz value.
     171 * Finally load in all flights into LAG/TerraScan (within a fence if memory issues) and check them (ideally along a stream because this has a “good” profile) Can use the travel path tool in TerraScan for comparing cross sections along a path.
    163172
    164173