Changes between Version 11 and Version 12 of Processing/TerrascanTips


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Timestamp:
Oct 22, 2008 12:12:42 PM (11 years ago)
Author:
mark1
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  • Processing/TerrascanTips

    v11 v12  
    1515
    1616=== Point classification ===
    17 This is an important part of the QC procedure to remove noisy points. You can make a macro and save it to use again. See the LIDAR notes on how to classify the points. Once classified we may want to strip the points of a certain classification off the LAS file. (Example - low points). This can be done by selecting "Point -> Delete -> By point class". Then select the class you want to delete. You can use "Classify -> Add point to ground" to add individual/groups of points to a certain class by selecting them. This is important because your classification routine will most likely misclassify some points.
     17This is an important part of the QC procedure to remove noisy points. You can make a macro and save it to use again. ''See the LIDAR notes for more info on how to classify the points''. Once classified we may want to strip the points of a certain classification off the LAS file. (Example - low points). This can be done by selecting "Point -> Delete -> By point class". Then select the class you want to delete. You can use "Classify -> Add point to ground" to add individual/groups of points to a certain class by selecting them. This is important because your classification routine will most likely misclassify some points.
    1818
    1919To remove haze layers, you can classify by elevation selecting points, say, >200m off the ground and classifying them as low points. It is suggested that all points to be removed be classified as low points (even if they are high).
     20
     21The main steps to set up a Macro are to select tools -> Macro.  Then classify "from any -> default" to get everything the same classification. Then "default -> low (group)", "default -> low (single)" and then classify isolated points "any -> low". This should classify all the overtly noisy points to low points. Test the macro at this stage and see if it is classifying correctly. If so, add the ground classification to the macro, "default -> ground" and re-test the macro. This is the basic ground classification macro.  Save it to a file for future re-use.