Changes between Version 14 and Version 15 of Procedures/AlsprocProcessing


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Timestamp:
Sep 2, 2014 11:44:01 AM (5 years ago)
Author:
stgo
Comment:

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  • Procedures/AlsprocProcessing

    v14 v15  
    122122The best method is to search for rooftops or other recognisable features both along and across areas of overlap using lag. It should look like this:
    123123
    124 [[Image(pitch_error_249-2012.jpg, align=center)]]
     124[[Image(pitch_error_249-2012.jpg, align=center, 50%)]]
    125125
    126126Using the ruler tool come up with the best possible approximate for lateral displacement both along and across the overlap. Normally this will be in the region of 50cm to 10cm. If the displacement is less than 5cm or 10cm in both directions then the files you have should be ok to use and you can use the pitch and roll errors you used for this attempt in your final solution. If not, you will need to estimate some new pitch and roll errors and try again. An example of acceptable pitch and roll errors is given below.
    127127
    128 [[Image(pitch_error_corrected_249-2012.jpg, align=center)]]
     128[[Image(pitch_error_corrected_249-2012.jpg, align=center, 50%)]]
    129129
    130130Determine the direction of your error. You need to decide whether to add or subtract from each of the pitch and roll error in the fields `pitch-correct` and `roll-correct` respectively. Look at the times of a few points in each flightline to determine each of their directions, and then decide whether you want to roll the angle of the laser clockwise or anticlockwise around the direction of travel of the plane to move the data left or right respectively; and whether you want to pitch up or down to move the data forwards or backwards respectively.