URL Decoding

CREATE FUNCTION dbo.fnDeURL
(
@URL VARCHAR(8000)
)
RETURNS VARCHAR(8000)
AS
BEGIN
DECLARE @Position INT,
@Base CHAR(16),
@High TINYINT,
@Low TINYINT,
@Pattern CHAR(21)

SELECT@Base = '0123456789abcdef',
@Pattern = '%[%][0-9a-f][0-9a-f]%',
@Position = PATINDEX(@Pattern, @URL)

WHILE @Position > 0
SELECT@High = CHARINDEX(SUBSTRING(@URL, @Position + 1, 1), @Base),
@Low = CHARINDEX(SUBSTRING(@URL, @Position + 2, 1), @Base),
@URL = STUFF(@URL, @Position, 3, CHAR(16 * @High + @Low - 17)),
@Position = PATINDEX(@Pattern, @URL)

RETURNREPLACE(@URL, '+', ' ')
END
E 12°55'05.25"
N 56°04'39.16"

EDIT: Decoding + as Jeff mentioned