ST_Roughness — Retourne un raster avec la rugosité d'un MNT.
raster ST_Roughness(raster rast, integer nband, raster customextent, text pixeltype="32BF" , boolean interpolate_nodata=FALSE );
Calcule la rugosité d'un MNT en soustrayant le maximum du minimum pour une zone donnée.
Disponibilité : 2.1.0
WITH foo AS (
SELECT ST_SetValues(ST_AddBand(ST_MakeEmptyRaster(5, 5, 0, 0, 1, -1, 0, 0, 0), 1, '32BF', 0, -9999),
1, 1, 1, ARRAY[
[1, 1, 2, 3, 3],
[1, 2, 4, 15, 3],
[2, 4, 10, 7, 5],
[3, 5, 7, 6, 4],
[3, 3, 5, 4, 4]
]::double precision[][]
) AS rast
)
SELECT ST_Value(ST_Roughness(rast, 1, '32BF'), 3, 3) AS roughness
FROM foo;
13
ST_MapAlgebra (callback function version), ST_TRI, ST_TPI, ST_Slope, ST_HillShade, ST_Aspect