Changes between Version 5 and Version 6 of Processing/laguserguide

Apr 4, 2012 10:56:12 AM (7 years ago)



  • Processing/laguserguide

    v5 v6  
    2424    The Resolution Depth determines the number of sub-buckets for each bucket and Resolution Base determines the number of points at each level by specifying the interval between included points based on the formula of Resolution Base^(Level - 1)^. For example the default values of 5 and 4 create 4 sub-buckets per bucket: one containing every point (5^0^), second containing every 5th point (5^1^), third containing every 25th point (5^2^) and fourth with every 125th point (5^3^). \\
    2525    Adjusting these values should be done carefully and based on the density, volume and coverage of the data. Generally increasing the Resolution Base and decreasing Resolution Depth will result in faster loading and quadtree operations (eg. classifying), but less smooth rendering. Creating more and denser sub-buckets may improve the interaction with the GUI but at the cost of slower quadtree and bigger memory footprint.
     26    For example for big flightlines that cover a vast area (like very long but thin lines, think 2011 29x London flights) it may be beneficial to create more sparse sub-buckets by increasing the Resolution Base. At the same time you can try to speed up loading times by decreasing the number of resolution levels, so values like 6 4 and 10 3 are worth testing.
    2627* **Points to hold in cache**
    2728    This determines the maximum number of points to hold in memory at any given time. Once this number is exceeded the points will be written to the hard drive which is much slower then RAM. This only concerns the quadtree and LAG is going to use much more together with OpenGL buffer and Gtk application. This value should be set roughly to 25% of you total available memory. Setting it too high will result in system memory swapping and setting it too low will result in quadtree uncaching data to hard drive. Note that points stored in memory are roughly 40% bigger then stored in the LAS files, so loading a 1GB file requires 1.4GB buffer.
    3435* **Keyboard Shortcuts**
    3536    The WASD cluster can be used for moving the camera (A - left, D - right, W - up, S down). The move speed can be changed in Advanced Options window. Additionaly: \\
    36 \\
    3738    B, G - zooms in and out \\
    3839    X - toggles the profile \\