Changes between Version 8 and Version 9 of Processing/laguserguide


Ignore:
Timestamp:
Apr 23, 2012 5:17:42 PM (7 years ago)
Author:
jaho
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • Processing/laguserguide

    v8 v9  
    1 = LAG User Guide [draft] =
     1= LAG User Guide =
    22
    33The following guide provides an overview of some of the LAG features and offers hints on how to utilize them for the best processing speed. Some of these are just convenient methods of doing things while other can offer a significant performance boost. Most of the values discussed below have been set up for the optimal performance by default, however different data sets and tasks can benefit from different configurations.
     
    5151
    5252* **Full refresh when panning**
    53     By default, when panning, rendered buckets are automatically refreshed every time a mouse button is released which may sometimes be slow. To disable this behaviour you can uncheck //Full refresh when panning// button in advanced options. This will make moving the camera much faster, but you'll have to manually refresh the view (by pressing Z) once you set the desired perspective.
     53    By default, when panning, rendered buckets are automatically refreshed every time a mouse button is released which may sometimes be slow. To disable this behaviour you can uncheck //Full refresh when panning// button in advanced options. This will make moving the camera much faster, but you'll have to manually refresh the view (by pressing Z or clicking //Refresh//) once you set the desired perspective.
    5454* **Detail level**
    5555    These values determine how many points should be displayed at given zoom level. Eg. the lower the value for the main overview detail level, the faster LAG will start using the sparse sub-buckets to display the data when zooming out. In case of the profile the higher the value, the less detailed the data. Profile main detail level should generally be left at 0, as different values may result in inaccurate visualisation. Profile preview detail level determines how much of profile's points are visible while panning.
     
    5858While 1.3 point format is fully supported, LAG makes no use of waveform data. You can however open and modify LAS 1.3 files and waveform data will be preserved __as long as you save it to another file__. If you attempt to save it to the same file the waveform part of the data will be lost.
    5959
     60== Projections ==
     61LAG currently supports UTM and latlong (or longlat: x = longitude, y = latitude) projections. By default files in both formats will be displayed using UTM coordinates. You can change it by going to //Tools >> Use latlong coordinates//.
     62
     63Latlong is generally a preferred projection because it doesn't require additional zone information. Latlong files can be saved as both latlong and UTM, while UTM files should not be converted, unless they contain projection information in the header's VLR geo keys. Alspp produced UTM files don't contain this information so this conversion should be avoided for the time being. Also latlong files seem to have higher precision than UTM files (up to about a 10th of a milimeter), which is probably much higher than the actual lidar precision. By default this values are rounded to precision of 1 centimeter when converting latlong to UTM. To prevent precision loss you can select // Use full precision // option on file saver dialog, however this will result in slightly bigger files.
     64
     65=== Test ===