[fdo-internals] Parsing WKT geoemtry with measure/dimensionality

[Paul Ramsey]

Hm, I'd feel more comfortable if there were some examples there... I  
have grown quite fond of the ISO representations in my old age...  
explicit and clear:

POINT (0 0)
POINT M (0 0 0)
POINT Z (0 0 0)
POINT ZM (0 0 0 0)

On Feb 26, 2008, at 6:57 AM, Gavin Cramer wrote:

> Microsoft's SQL Server 2008 documents itself as supporting WKT  
> augmented with Z and M:
>
>   http://msdn2.microsoft.com/en-us/library/bb933823(SQL.100).aspx
>
> It does appear to have done it with the same syntactic extensions  
> for ordinate dimensionality as OGC does.
>
> Gavin
>
>
> -----Original Message-----
> From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org 
> ] On Behalf Of Orest Halustchak
> Sent: Tuesday, February 26, 2008 8:21 AM
> To: FDO Internals Mail List
> Subject: RE: [fdo-internals] Parsing WKT geoemtry with measure/ 
> dimensionality
>
> Hi,
>
> Frank is correct that the FGF format was defined prior to the OGC  
> working on the updated spec for wkb and wkt to support Z and M. I  
> agree that FDO should be enhanced to support the new OGC spec. I'll  
> add an entry to the FDO Futures wiki page for it and hopefully at  
> some point someone will put together an RFC for it.
>
> What other systems do we know about that have added support for the  
> updated Simple Features Spec?
>
> Thanks,
> Orest.
>
> -----Original Message-----
> From: fdo-internals-bounces at lists.osgeo.org [mailto:fdo-internals-bounces at lists.osgeo.org 
> ] On Behalf Of Frank Warmerdam (External)
> Sent: Monday, February 25, 2008 4:27 PM
> To: FDO Internals Mail List
> Subject: Re: [fdo-internals] Parsing WKT geoemtry with measure/ 
> dimensionality
>
> Simon Pelicon wrote:
>>
>> Hi!
>> I have a problem parsing WKT geometry with M or Z dimension.
>> For example in WKT documentation specification, point with M is  
>> defined
>> as in the example below:
>> Point M (10 10 40)
>>
>> But parsing this to geometry in FDO returns this error:
>> m_cause = 0x01693a30 {m_message=0x01693a80
>> "(.\Src\Geometry\Parse\ParseFgft.cpp: 88) String is not a valid FGF
>> string. "
>>
>> Fdo documentation says that: The Autodesk extension to WKT,  
>> referred to
>> as FGF Text, is a superset of WKT
>> (that is, you can enter WKT as valid FGF Text strings).  
>> Dimensionality
>> is optional. It can be XY, XYM, XYZ, or XYZM.
>>
>> I am confused about dimensionality specification now.
>> WKT specification puts only M or ZM ,but FDO requires XY in front  
>> of M
>> or ZM.
>
> Simon,
>
> I think the problem is that you are looking at the "new" Simple  
> Features
> geometry specification, while FDO's FGF parser was written to the old
> one.  The new specification was only released within the last year I
> think.
>
> It certainly would be desirable (in my mind) for the FDO geometry  
> parser
> to support both variations to the extent possible.
>
> BTW, the old simple features geometry specification did not include
> Z or M dimensions though there were some common approaches to  
> supporting
> them in use in the wild.
>
> Best regards,
> --
> --------------------------------------- 
> +--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | President OSGeo, http://osgeo.org
>
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--
Paul Ramsey
pramsey at cleverelephant.ca
+1 250 885 0632