[OSGeo-Standards] Re: FW: [MetaCRS] 'FOSS Maintained' Source ofCRSDefinitions

Thu May 8 13:09:42 EDT 2008

You may download (for free) 19111 from the OGC website. 
http://www.opengeospatial.org/standards/as The current version is a bit 
dated. The OGC members are currently voting on approving the latest version. 
19111 is a joint OGC-ISO document. OGC Members can log into the portal and 
download the 2007 version of 19111.

Regards

Carl

----- Original Message ----- 
From: "Landon Blake" <lblake at ksninc.com>
To: <arnulf.christl at wheregroup.com>; <metacrs at lists.osgeo.org>
Cc: <standards at lists.osgeo.org>
Sent: Thursday, May 08, 2008 8:03 AM
Subject: RE: [OSGeo-Standards] Re: FW: [MetaCRS] 'FOSS Maintained' Source 
ofCRSDefinitions

> Arnulf,
>
> Has the ISO spec that Martin mentioned moved trough the OGC? If so,
> wouldn't we be able to download it from the OGC website?
>
> Just curious...
>
> Landon
>
> -----Original Message-----
> From: standards-bounces at lists.osgeo.org
> [mailto:standards-bounces at lists.osgeo.org] On Behalf Of Arnulf Christl
> Sent: Thursday, May 08, 2008 12:29 AM
> To: metacrs at lists.osgeo.org
> Cc: standards at lists.osgeo.org
> Subject: [OSGeo-Standards] Re: FW: [MetaCRS] 'FOSS Maintained' Source of
> CRSDefinitions
>
>
> On Wed, May 7, 2008 18:30, Landon Blake wrote:
>> Frank wrote: "Can you point us to a public document on this model?"
>>
>>
>> This might be an issue with the ISO spec. You have to pay for copies
> of
>> ISO specs if I remember correctly. They are also protected by
> copyright,
>> which might be another issue for some of us.
>
> Another side note: One thing that OGC is adamant about is to publish
> standards openly and royalty free. All ISO standards that have gone
> through ISO TC211 and were developed with involvement by OGC members are
> therefore also available for free. Cool thing I'd say.
>
> Apart from that it is obviously easier to just hack into an existing
> library that already implements standards like GeoTools and GeoAPI does.
> Whenever you do need to look into the original papers and cannot find
> them
> let the standards list now. Several OGC members are involved with
> FOSSGIS
> and OGC has offered several slots to OSGeo to be used by independent
> developers to access documents still under development. If you need more
> information please let me know, I am happy to act as enabler.
>
> Regards,
>
>>> From the ISO FAQ:
>>>
>>
>> Are any ISO standards available electronically?
>>
>>
>> Some ISO standards are available as electronic products. Contact the
> ISO
>> member in your country or our sales department using the online
> contact
>> form.
>>
>>
>> Where can I obtain technical assistance on standards?
>>
>>
>> Contact the ISO member in your country. A list of members can be
>> accessed on this site. The ISO Central Secretariat does not provide
>> technical assistance, but the online enquiry service may be able to
> help
>> you save time by directing you to appropriate sources of information.
>>
>> Can I reproduce material from ISO standards?
>>
>>
>> All ISO publications, including ISO standards, are protected by
>> copyright. See the ISO copyright guide page for further information.
>>
>> The web page for the newest version of the ISO 19111 spec being
>> developed is here:
>>
>>
> http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.
>> htm?csnumber=44075
>>
>> Frank wrote: " I'd be interested to hear from the CS-MAP folks if they
>> model datum shifts between arbitrary datums, as opposed to mapping
>> everything through WGS84 (as PROJ4 is inclined to do)."
>>
>>
>> We talked about this at OpenJUMP a few months back. It seems design of
> a
>> CRS library is simpler if you use WGS84 as the common currency for
>> transformations, but it adds overhead for some more simple
> transformations.
>> For example, you don't need to convert to WGS84 to go
>> from California State Plane Coordinates in US Survey Feet to
> California
>> State Plane Coordinates in Metric units. You just scale. We had
> thought
>> a solution would be to break transformations into two (2) types.
> Simple
>> transformations that could be performed with scaling, rotation, and an
>> elevation shift, and everything else, which would use WGS84 as a
> medium.
>>
>> Frank wrote: " A few limitations to WKT that I am concerned about..."
>>
>>
>> Could we extend the format? I don't really think it is critical that
> we
>> use WKT. As long as we have something that is human readable text, and
> not
>> locked up in a relational database.
>>
>> The only advantage of an extended WKT format is that it is already
> known
>> to a lot of programmers.
>>
>> Frank wrote: " When talking about dictionaries I would prefer not to
> get
>> hung up on API specifications.  I'd prefer to manage and provide a
>> dictionary in some form suitable exploitation by different packages
> and
>> leave it to them to talk about APIs."
>>
>> I agree. I'm speaking to Jody about setting up a mailing list that can
>> host discussions on collaboration between Java projects.
>>
>> Landon
>>
>>
>>
>> -----Original Message-----
>> From: metacrs-bounces at lists.osgeo.org
>> [mailto:metacrs-bounces at lists.osgeo.org] On Behalf Of Frank Warmerdam
>> Sent: Wednesday, May 07, 2008 8:24 AM
>> To: Martin Desruisseaux
>> Cc: metacrs at lists.osgeo.org
>> Subject: Re: [MetaCRS] "FOSS Maintained" Source of CRS Definitions
>>
>>
>> Martin Desruisseaux wrote:
>>
>>> There is already an existing model, which is an international
> standard
>>>
>>
>>> approved both by ISO and OGC: ISO 19111. Would it be an acceptable
>> model?
>>
>> Martin,
>>
>>
>> Can you point us to a public document on this model?  I'm frankly
>> somewhat intimidated by it, and concerned that a lot of stuff it
> describes
>> is not practically useful.  But I really need to do a current review
>> before I spout off much more.
>>
>>>>> There is already a "standard" and open format for CRS definitions,
>>>>> namely WKT, correct? Couldn't this be used?
>>>
>>> It can be used for "minimal" CRS definition. But the OGC standard WKT
>>> can not express Bursa-Wolf parameters targeting any other datum than
>>> WGS84, and can not contain useful metadata like area of validity. Yet
>>>
>> it
>>> still applicable when there is nothing better. But when a choice is
>>> possible, I rather push for the EPSG database.
>>
>> I'd be interested to hear from the CS-MAP folks if they model datum
>> shifts between arbitrary datums, as opposed to mapping everything
> through
>> WGS84 (as PROJ4 is inclined to do).
>>
>>
>> A few limitations to WKT that I am concerned about:
>> * There is no way to express datum shift methods other than 3/7
>> parameter transformations to wgs84 (via TOWGS84).  In particular, how
> am I
>> supposed to document use of grid shift files in WKT? * There is no way
> to
>> express that there are more than one possible datum shift
> approximation
>> available for use. * No way to mark coordinate systems as deprecated,
>> categorize them for display to the user and such.  If we produce a
> "super
>> dictionary" it would be nice if user interfaces could provide a useful
>> navigation mechanism to user based on it.
>>
>> I can imagine picking the ISO model as our central CRS data model, and
>> distributing definitions in some format that maps well to that model,
> like
>> GML, but I'm concerned we make our dictionaries so complicated that
> they
>> become very difficult to exploit.
>>
>>> As far as I known the EPSG database is the most widely accepted at
>>>
>> least
>>> at OGC. Some other sources like the PostGIS "spatial_ref_sys" table
>> are
>>> actually generated from a subset of the EPSG database.
>>
>> The EPSG database will certainly be a large portion of a
>> super-dictionary. However, I would like to be able to capture other
>> coordinate system dictionaries too.  A few of interest to me:
>>
>> * The datum list from NGA, as used in GeoTrans.
>> * The ESRI "coded" extensions to EPSG.
>> * The ERMapper projection and datum definitions.
>> * The MapInfo datum list.
>> * The IAU (International Astronomical Union) definitions for other
>> planets. * OGC authority space definitions like
> urn:ogc:def:crs:OGC::CRS84
>>
>>
>> I should also point out http://spatialreference.org/ as a point of
>> interest in our discussions.  This web site maintains it's own list of
> CRS
>> definitions, many user submitted, though starting from the EPSG set.
> It
>> effectively stores them internally as WKT (I think) but endevors to
> return
>> them in a variety of formats (using OGRSpatialReference facilities to
> do
>> the translation).
>>
>>>> - CRS interface spec. (not necesary but would be nice)
>>>>
>>>
>>> GeoAPI ?
>>>
>>
>> When talking about dictionaries I would prefer not to get hung up on
>> API specifications.  I'd prefer to manage and provide a dictionary in
>> some form suitable exploitation by different packages and leave it to
> them
>> to talk about APIs.
>>
>> I'm keen on GeoAPI as a basis for shared Java coordinate system
>> libraries but I would like to keep that discussion distinct from the
>> dictionary discussion if possible.  Obviously starting from an ISO
> model
>> (or
>> perhaps a subset of the ISO model) makes it easier to map the
> dictionary to
>>  something like GeoAPI.
>>
>> 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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>>
>>
>>
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>>
>>
>
>
> -- 
> Arnulf Christl
> http://www.wheregroup.com
>
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> Warning:
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> not the intended recipient, you are hereby notified that any 
> dissemination, distribution or copying of this communication is strictly 
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