[ldap] Re: LDAP attributes for geographic ``variables''?
Ivan Shmakov wrote: Kurt Zeilenga Kurt.Zeilenga... writes: [...] As an alternative approach, I would suggest having a single multi-valued attribute that would contain URIs expressing the location of the attribute. This would push various issues, such as which location system is being used, out to the URIs. This is a good thing as such issues are not unique to LDAP/X.500. I've never heard of the geographic coordinates being encoded as an URI. Could you please give any references on that matter (if there're any)? There are examples in the draft the Kurt listed above. FYI: http://www.ietf.org/id/draft-ietf-geopriv-geo-uri-01.txt -- Kind Regards, Gavin Henry. Managing Director. T +44 (0) 1224 279484 M +44 (0) 7930 323266 F +44 (0) 1224 824887 E ghe...@suretecsystems.com Open Source. Open Solutions(tm). http://www.suretecsystems.com/ Suretec Systems is a limited company registered in Scotland. Registered number: SC258005. Registered office: 13 Whiteley Well Place, Inverurie, Aberdeenshire, AB51 4FP. Subject to disclaimer at http://www.suretecgroup.com/disclaimer.html
[ldap] Re: LDAP attributes for geographic ``variables''?
Gavin Henry ghenry... writes: Ivan Shmakov wrote: Kurt Zeilenga Kurt.Zeilenga... writes: As an alternative approach, I would suggest having a single multi-valued attribute that would contain URIs expressing the location of the attribute. This would push various issues, such as which location system is being used, out to the URIs. This is a good thing as such issues are not unique to LDAP/X.500. I've never heard of the geographic coordinates being encoded as an URI. Could you please give any references on that matter (if there're any)? There are examples in the draft the Kurt listed above. FYI: http://www.ietf.org/id/draft-ietf-geopriv-geo-uri-01.txt It was noted (e. g., the thread started with [1]) that the goals of this scheme are simplicity, interoperability and human-readability, hence the choice of a single coordinate system (WGS 84) in wide use today. However, for the purposes of passing location references in a mixed-coordinate system environment (and the geospatial applications use a sheer variety of these), the only coordinate system is not enough. Also, while the newer revisions of the draft are expected to allow for the spatial uncertainty to be specified, this specification is to be made in meters, which also has some implications (consider, e. g., [2]; well, to put it simple, consider that a temperature in Celsius degrees is given an uncertainty value in Fahrenheit; and when it comes to the spatial coordinates the issue is even worse.) Therefore, while the geo: URI may be taken as the basis, its use (in its current form) for geospatial metadata (which is my primary interest) doesn't seem feasible. [1] http://www.ietf.org/mail-archive/web/geopriv/current/msg07711.html [2] http://www.ietf.org/mail-archive/web/geopriv/current/msg07695.html -- FSF associate member #7257
[ldap] Re: LDAP attributes for geographic ``variables''?
Gavin Henry wrote: Ivan Shmakov wrote: Kurt Zeilenga Kurt.Zeilenga... writes: [...] As an alternative approach, I would suggest having a single multi-valued attribute that would contain URIs expressing the location of the attribute. This would push various issues, such as which location system is being used, out to the URIs. This is a good thing as such issues are not unique to LDAP/X.500. I've never heard of the geographic coordinates being encoded as an URI. Could you please give any references on that matter (if there're any)? There are examples in the draft the Kurt listed above. FYI: http://www.ietf.org/id/draft-ietf-geopriv-geo-uri-01.txt Despite the comments Ivan gave in another posting I wonder how to implement ORDERING matching rules for this. Ciao, Michael.
[ldap] Re: LDAP attributes for geographic ``variables''?
As an alternative approach, I would suggest having a single multi- valued attribute that would contain URIs expressing the location of the attribute. This would push various issues, such as which location system is being used, out to the URIs. This is a good thing as such issues are not unique to LDAP/X.500. -- Kurt On Jul 27, 2009, at 10:19 AM, Ivan Shmakov wrote: Adam Tauno Williams awilliam... writes: Hello. Is there a standardized (or regularly used) attribute defined for continents, besides country, st, locality? Not that I've ever seen. There are a couple of definitions of longitude/latitude floating about, but nothing for continent. I wonder, what other geographic ``variables'' (or objects?) have found their way to LDAP? To put it differently, the (latitude, longitude) pair describes a point on the Earth's surface. Are there existing LDAP attributes (or object classes?) that will allow one to describe more complex ``features'' upon the Earth's surface, such as, e. g., polygons? Debian: attributetype ( 1.3.6.1.4.1.9586.100.4.2.7 NAME 'latitude' DESC 'latitude coordinate' EQUALITY caseExactIA5Match SUBSTR caseExactIA5SubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 SINGLE-VALUE ) And also: --cut: http://openosi.org/osi/display/oid/1.3.6.1.4.1.27630.2.1.1.23 -- attributetype ( 1.3.6.1.4.1.27630.2.1.1.23 NAME ( 'osiLatitude' 'latitude' ) DESC 'Latitude in decimal degree notation, negative sign for South' EQUALITY caseExactIA5Match SUBSTR caseExactIA5SubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 SINGLE-VALUE ) ... SYNONYM OID * 1.3.6.1.4.1.9586.100.4.2.7 (Debian userdir-ldap.schema) --cut: http://openosi.org/osi/display/oid/1.3.6.1.4.1.27630.2.1.1.23 -- [...] GNOME has defined it as well: attributetype ( 1.3.6.1.4.1.3319.7.7 NAME 'latitude' DESC 'latitude coordinate' EQUALITY caseExactIA5Match SUBSTR caseExactIA5SubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 SINGLE-VALUE ) Seems to be not used much, as Google lists only two matches for the OID. [...] -- FSF associate member #7257
[ldap] Re: LDAP attributes for geographic ``variables''?
Kurt Zeilenga wrote: As an alternative approach, I would suggest having a single multi-valued attribute that would contain URIs expressing the location of the attribute. This would push various issues, such as which location system is being used, out to the URIs. This is a good thing as such issues are not unique to LDAP/X.500. Is there anything like this already defined/used somewhere? Ciao, Michael.
[ldap] Re: LDAP attributes for geographic ``variables''?
On Jul 27, 2009, at 11:16 AM, Michael Ströder wrote: Kurt Zeilenga wrote: As an alternative approach, I would suggest having a single multi- valued attribute that would contain URIs expressing the location of the attribute. This would push various issues, such as which location system is being used, out to the URIs. This is a good thing as such issues are not unique to LDAP/X.500. Is there anything like this already defined/used somewhere? The geo: URI is a work in progress http://www.ietf.org/id/draft-ietf-geopriv-geo-uri-01.txt . I think it would be good to define an LDAP/X.500 attribute type to hold any URI that represents the geographical location of the object, recommending use of geo: but allow for other schemes as might become available. Of course, one could just put a geo: URI in labeledURI... but I don't recommend doing this. -- Kurt
[ldap] Re: LDAP attributes for geographic ``variables''?
Kurt Zeilenga Kurt.Zeilenga... writes: [...] As an alternative approach, I would suggest having a single multi-valued attribute that would contain URIs expressing the location of the attribute. This would push various issues, such as which location system is being used, out to the URIs. This is a good thing as such issues are not unique to LDAP/X.500. I've never heard of the geographic coordinates being encoded as an URI. Could you please give any references on that matter (if there're any)? -- FSF associate member #7257
