Re: Best Practice for encoding spatial coverage

Lars,

the new WKT for CRS (ISO 19162 or http://docs.opengeospatial.org/is/12-063r5/12-063r5.html) is a lot clearer on this than the Geometry WKT specs were. I expect that future revisions of the Geometry WKT will follow the same rules, too.

Case sensitivity: http://docs.opengeospatial.org/is/12-063r5/12-063r5.html#18
Whitespace in WKT: http://docs.opengeospatial.org/is/12-063r5/12-063r5.html#138
Whitespace in the BNF: http://docs.opengeospatial.org/is/12-063r5/12-063r5.html#7

Clemens



> On 19 Jun 2015, at 17:45, Svensson, Lars <L.Svensson@dnb.de> wrote:
> 
> Andrea,
> 
> Sorry, but I can't resist a comment on WKT:
> 
>> - it is case and "space" insensitive - i.e., all the following
>> variants are valid: " point(0 0)" "PoinT ( 0  0)", " POINT(0  0 )  "
> 
> The specification of WKT in SFA [1] says _in the text_ that " Well known text is case insensitive." (§ 7.2.1). The BNF does not reflect this though. E. g. for "point" it states 
> 
> <point tagged text> ::= point <point text> 
> 
> Further, the specification say nothing at all about whitespace when defining a point:
> 
> <point text> ::= <empty set> | <left paren> <point> <right paren> 
> <point> ::= <x> <y>
> <x> ::= <signed numeric literal>
> <y> ::= <signed numeric literal>
> <signed numeric literal> ::= {<sign>}<unsigned numeric literal>
> <unsigned numeric literal> ::= <exact numeric literal>
> 				|<approximate numeric literal>
> <exact numeric literal> ::= <unsigned integer>
> 				{<decimal point>{<unsigned integer>}}
> 				|<decimal point><unsigned integer>
> <approximate numeric literal> ::= <mantissa>E<exponent>
> <mantissa> ::= <exact numeric literal>
> <exponent> ::= <signed integer>
> <signed integer> ::= {<sign>}<unsigned integer>
> <unsigned integer> ::= (<digit>)*
> 
> I stumbled over this when I tried to use the BNF to create a validator for WKT...
> 
> [1] http://portal.opengeospatial.org/files/?artifact_id=25355
> 
> Best,
> 
> Lars