Water - JiriVales/automatic-creation-orienteering-map GitHub Wiki

Create water area (LIDAR points)

Picture: Model Create water area (LIDAR points)

Algorithm description

Instrument for creating water areas using areas where the number of reflected points is zero or minimal (laser aviation scanning has been absorbed).
Used tools: Kernel density estimation (SAGA), Invert data/no-data (SAGA), Polygonize (raster to vector). Field calculator, Fill holes, Fixed distance buffer, Extract by attribute, Simplify geometries, v.generalize.smooth

Input parameters

LIDAR points
Layer of LIDAR points.
Format: vector, points
Minimum area of the water area
Format: number
Units: meters
Default value: 500
Radius (density estimation)
Parameter of Kernel density estimation. Radius. It hangs on the average point density.
Format: number (0.5 - 500, can be decimal)
Units: meters
Default value: 5.0
Density estimation: cellsize
Parameter of Kernel density estimation. Grid pixel size.\ Format: number (0.1 - 500, can be decimal)
Units: meters
Default value: 2.0
Maximal tolerance value (v.generalize.smooth)
Parameter for smoothing polygon boundary using Chaiken algorithm. Distance between the created points at the polygon boundary.
Format: integer (0 - 500)
Units: meters
Default value: 2
Tolerance (Simplify geometries)
Parameter of Simplify geometries. The maximum distance between the original and the generalized polygon boundary.
Format: integer (0 - 500)
Units: meters
Default value: 2
Enlarge of polygon of the water area (meters)
During the use of the Kernel density estimation tool, the water surface was reduced by value of Radius. This parameter is used to re-magnify it. It is advisable to enter the same value as the Radius parameter.
Format: number (0.1 - 1000, can be decimal)
Units: meters
Default value: 5.0

Outputs

Water_area
Layer of water areas.
Format: vector, polygon Picture: Created water areas (red)