Re: lat/long as float

Takagi -

The use of 6709 has been discussed in various non-ISO forums, such as the IETF, OASIS, and the OGC. While aspects of 6709 are valid for the expression of coordinates in XML or other serializations (see below my signature), the OGC membership has identified some issues with 6709 in terms of implementation reality. The OGC sent the following comments to ISO WRT 6709:

OGC has an objection regarding ISO 6709 entering the enquiry stage.

The proposed DIS for 6709 (TC211 N-doc 1939) contains these annexes:
 Annex F (informative) - Utilization of Geographic Point Locations 
 Annex G (informative) - Examples of XML representation.


Annexes F and G of ISO 6709 will be confusing as ISO members are currently considering XML encoding of geographic points in GML (ISO 19136).


Previously it was concluded that no GML examples can be given in 6709 because GML uses decimal degrees only for all geographic coordinate.


Although ISO 6709 uses a Degrees-Minutes-Seconds representation of coordinates in an XML exchange, we question the usefulness of the examples, since they are arbitrary instance examples and there is no schema for such coordinates.


Thus, OGC recommends that Annex G and Annex F be removed from ISO 6709 before it is sent to the ISO Central Secretariat for publication as DIS.

That said, if one considers the snippet from the 6709 document (below my name), we find that GeoRSS, GML, the OASIS work using lat/long, and the IETF use of lat/long for points all adhere to the stated clauses.

Regards

Carl Reed
OGC

The following from 6709  is valid for any and all work related to encoding of lat/long:

Clause
2.1.1, 2.2.1 in action:

2.1 Latitude
2.1.1 Latitudes north of the equator shall
be designated by use of the plus sign (+),
latitudes south of the equator shall be
designated by use of the minus sign (-).
The equator shall be designated by use
of the plus sign (+).
...
2.2 Longitude
2.2.1 Longitudes east of Greenwich shall be
designated by use of the plus sign (+),
longitudes west of Greenwich shall be
designated by use of the minus sign (-).
The Prime Meridian shall be designated
by use of the plus sign (+). The 180th
meridian shall be designated by use of
the minus sign (-). 2.4 Format
...
2.4 Format
2.4.1 Elements shall be combined in a point location string in the
sequence :
a) latitude;
b) longitude;
c) altitude, if represented.

----- Original Message ----- 
From: "Satoru Takagi" <satoru.takagi@ubin.jp>
To: <public-xg-geo@w3.org>
Sent: Thursday, July 27, 2006 9:45 PM
Subject: Re: lat/long as float


> 
>>All coordinates in this profile shall, as a default, be expressed as
> Latitude Longitude (in that order) as decimal degrees white space separated.
> 
> Quite a lot of notations for latitude longitude (and altitude , crs)
> information exist in the world.
> There might be each advantage and a disadvantage respectively.
> However, I think that it is desirable that they are few. For the
> improvement of the interoperability.
> I think that it can settle to the following two notations by simply
> thinking.
> 
> Methods of separately describing latitude and longitude. Methods of
> description as one character string.
> 
> In a lot of usages, latitude and the longitude will be considered to be
> inseparable one resource.
> Casual use cases such as microformats (geo improvements), WikiProject
> Geographical coordinates, and geoRSS might be the examples.
> Though they are all different formats.
> #Methods of divided description as a different attribute are omitted
> because there are a lot of examples.
> 
> Well, I think that it is necessary to consider ISO6709/1983 as an
> important candidate in such a situation for one character string format.
> 
> 
>