[Esip-documentation] ACDD comments

[Bob Simons - NOAA Federal via Esip-documentation]

It is me (Bob).

1) Your first answer implies that the numbers in geospatial_bounds must be
latitude in degrees_north and longitude in degrees_east and meters up (what
datum?) (as opposed to x,y from some projection).  If so, the definition
should say so explicitly.  Otherwise, how am I to know if the WKT has
lat/lon or x/y? So many datasets use projections, so the coordinates for
the data are x and y from the projection.

Okay, if geospatial_bounds and geospatial_lat/lon_min/max all use latitude
in degrees_north, longitude in degrees_east, meters up (what datum?), and
the same coordinate system, great.  But, uh, in which attribute is that
coordinate system specified?

2) I agree with you. I am not an expert, but I have never seen a WKT
geometry that includes a coordinate system.  If we are using EWKT, then the
definition should say so and give an example and/or a reference.

On Thu, Sep 18, 2014 at 7:23 PM, Aleksandar Jelenak via Esip-documentation <
esip-documentation at lists.esipfed.org> wrote:

> Hi Bob,
>
> (I assume it’s you because the ESIP mailing list server seems to have
> started obfuscating sender’s info.)
>
> On 9/18/14, 7:20 PM, "ESIP Documentation LIst"
> <esip-documentation at lists.esipfed.org> wrote:
> >But my original question was: for the geospatial_bounds attribute (which
> >is a WKT representation of a geometry), what are the units of the numbers
> >and what is the coordinate system used in the geometry?
>
> My answer: the same CRS that would apply if the
> geospatial_{lat|lon}_{min|max} attributes were used. The description for
> the geospatial_bounds should be amended to clarify this.
>
> >I see examples of WKT geometries (without units and without a coordinate
> >system) for example on Wikipedia, e.g.,
> >POLYGON ((30 10, 40 40, 20 40, 10 20, 30 10))
> >and I see examples of WKT coordinate systems (e.g., below).
> >But I still haven't seen a WKT geometry example which includes units and
> >a coordinate system.
>
> I am not an expert on the WKT format but I’d say it is not currently
> possible to combine a CRS declaration with a geospatial object’s extent
> definition. PostGIS introduced a non-standard extension, EWKT, where a CRS
> can be declared, e.g.: “SRID=4326;POLYGON(…)”.
>
>         -Aleksandar
>
> _______________________________________________
> Esip-documentation mailing list
> Esip-documentation at lists.esipfed.org
> http://www.lists.esipfed.org/mailman/listinfo/esip-documentation
>



-- 
Sincerely,

Bob Simons
IT Specialist
Environmental Research Division
NOAA Southwest Fisheries Science Center
1352 Lighthouse Ave
Pacific Grove, CA 93950-2079
Phone: (831)333-9878 (New as of 2014-08-20)
Fax:   (831)648-8440
Email: bob.simons at noaa.gov

The contents of this message are mine personally and
do not necessarily reflect any position of the
Government or the National Oceanic and Atmospheric
Administration.
<>< <>< <>< <>< <>< <>< <>< <>< <><
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.lists.esipfed.org/pipermail/esip-documentation/attachments/20140918/4a6e5720/attachment.html>