pggeodb.nancy.inra.fr/db_cefs - db_cefs on pggeodb.nancy.inra.fr

Function: _st_roughness4ma

Schema

public

Owner

postgres

Descriptions

There is no description for function _st_roughness4ma

Options

Definition

CREATE OR REPLACE FUNCTION public._st_roughness4ma (
 value double precision [],
 pos integer [],
 variadic userargs text [] = NULL::text[]
)
RETURNS double precision AS
$span$
DECLARE
x integer;
y integer;
z integer;

minimum double precision;
maximum double precision;

_value double precision[][][];
ndims int;
BEGIN

ndims := array_ndims(value);
-- add a third dimension if 2-dimension
IF ndims = 2 THEN
_value := _st_convertarray4ma(value);
ELSEIF ndims != 3 THEN
RAISE EXCEPTION 'First parameter of function must be a 3-dimension array';
ELSE
_value := value;
END IF;

-- only use the first raster passed to this function
IF array_length(_value, 1) > 1 THEN
RAISE NOTICE 'Only using the values from the first raster';
END IF;
z := array_lower(_value, 1);

IF (
array_lower(_value, 2) != 1 OR array_upper(_value, 2) != 3 OR
array_lower(_value, 3) != 1 OR array_upper(_value, 3) != 3
) THEN
RAISE EXCEPTION 'First parameter of function must be a 1x3x3 array with each of the lower bounds starting from 1';
END IF;

-- check that center pixel isn't NODATA
IF _value[z][2][2] IS NULL THEN
RETURN NULL;
-- substitute center pixel for any neighbor pixels that are NODATA
ELSE
FOR y IN 1..3 LOOP
FOR x IN 1..3 LOOP
IF _value[z][y][x] IS NULL THEN
_value[z][y][x] = _value[z][2][2];
END IF;
END LOOP;
END LOOP;
END IF;

minimum := _value[z][1][1];
maximum := _value[z][1][1];

FOR Y IN 1..3 LOOP
   FOR X IN 1..3 LOOP
    IF _value[z][y][x] < minimum THEN
   minimum := _value[z][y][x];
ELSIF _value[z][y][x] > maximum THEN
   maximum := _value[z][y][x];
END IF;
   END LOOP;
END LOOP;

RETURN maximum - minimum;
END;
$span$
LANGUAGE 'plpgsql'
IMMUTABLE
CALLED ON NULL INPUT
SECURITY INVOKER
COST 100;

This file was generated with SQL Manager for PostgreSQL (www.pgsqlmanager.com) at 13/03/2014 13:23