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nsw_lidar [2019/02/10 21:28]
bushwalking
nsw_lidar [2019/02/22 21:37] (current)
bushwalking
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 The raw stream data is very jagged. Smooth using  The raw stream data is very jagged. Smooth using 
   * v.generalize   * v.generalize
-  * Algorithm = Hermite (there are other options which can be used) +  * Algorithm = Hermite (there are other options which can be used, but Hermite has the smoothed line passing through the points of the original
   * Maximal tolerance value = 20 (in m, obviously scale dependent)   * Maximal tolerance value = 20 (in m, obviously scale dependent)
  
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 ===== Clifflines ===== ===== Clifflines =====
  
-The steps below have been tested ​in the Blue Mountains, a region that has a significant number of relatively vertical sandstone cliffs. It may be less effective in different terrain.+The steps below are being developed for use in the Blue Mountains, a region that has a significant number of relatively vertical sandstone cliffs. It may be less effective in different terrain.
  
 This is more a set of ideas than a fully fledged process. The main aims are to get a set of steps that can largely be automated, and that create cliffline vectors that are running in the correct direction. There is still some way to go on this! This is more a set of ideas than a fully fledged process. The main aims are to get a set of steps that can largely be automated, and that create cliffline vectors that are running in the correct direction. There is still some way to go on this!
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 using DEM and [1] Maximum Triangle Slope (Tarboton (1997)). I haven'​t tested any other algorithms. ​ using DEM and [1] Maximum Triangle Slope (Tarboton (1997)). I haven'​t tested any other algorithms. ​
   
-Cliff areas can be identified using a range of 60-90 and 70-90 degrees on the Slope file. Using 60-90 degrees helps connect logical cliffs and avoid small breaks.+Cliff areas can be identified using a range of say 60-90 and 70-90 degrees on the Slope file. Using 60-90 degrees helps connect logical cliffs and avoid small breaks.
  
 ==== Initial Cleaning ==== ==== Initial Cleaning ====
  
 Next convert data to 1 bit (1,2 not 0,1, as Sieve ignores 0s) using Raster Calculator. Next convert data to 1 bit (1,2 not 0,1, as Sieve ignores 0s) using Raster Calculator.
-Formula is: (Slope > 0) + 1+Formula is: (Slope > 60) + 1
  
 Then Sieve resulting data using a Threshold of 100 and 8-connectedness to get rid of small non-connected cliffs. Note above that Sieve doesn'​t like 0s. Then Sieve resulting data using a Threshold of 100 and 8-connectedness to get rid of small non-connected cliffs. Note above that Sieve doesn'​t like 0s.
nsw_lidar.txt ยท Last modified: 2019/02/22 21:37 by bushwalking