Database Reference
In-Depth Information
ST_AsRaster(ST_Transform(sf.geom, 3310),
r.rast) A
S rast
FROM sfpoly sf
CROSS JOIN r
)
SELECT
ST_Clip(ST_HillShade(r.rast, 1,
cx.rast), S
T_Transform(sf.geom, 3310)) AS rast
FROM r
CROSS JOIN cx
CROSS JOIN sfpoly sf;
Inthiscase,
ST_HillShade()
isadrop-inreplacementfor
ST_Slope()
because
wedonotspecifyanyspecialinputparametersforeitherfunction.Ifweneedtospe-
cify additional arguments for
ST_Slope()
or
ST_HillShade()
, all changes are
confined to just one line.
ThefollowingscreenshotshowstheSRTMrasterbeforeandafterprocessingitwith
ST_Slope()
and
ST_HillShade()
:
Asyoucanseeinthescreenshot,theslopeandhillshaderastershelpusbetterun-
derstand the terrain of San Francisco.
