[Esip-documentation] proposed new wording for geospatial bounds attributes -- updated

[Aleksandar Jelenak via Esip-documentation]

Dear all:

Couple of weeks ago Jim Biard, John Graybeal, Bob Simons and me worked on
finalizing the proposal for the geospatial_bounds family of attributes. We
decided that three attributes are needed and they are listed below:

geospatial_bounds:


Describes the data's 2D or 3D geospatial extent in OGC's Well-Known Text
(WKT) Geometry format (reference the OGC Simple Feature Access (SFA)
specification). The meaning and order of values for each point's
coordinates depends on the coordinate reference system (CRS). The ACDD
default is 2D geometry in the EPSG:4326 coordinate reference system. The
default may be overridden with geospatial_bounds_crs and
geospatial_bounds_vertical_crs (see those attributes). EPSG:4326
coordinate values are latitude (decimal degrees_north) and longitude
(decimal degrees_east), in that order. Longitude values in the default
case are limited to the [-180, 180) range. Example: "POLYGON ((40.26
-111.29, 41.26 -111.29, 41.26 -110.29, 40.26 -110.29, 40.26 -111.29))”.




geospatial_bounds_crs:


The coordinate reference system (CRS) of the point coordinates in the
geospatial_bounds attribute. This CRS may be 2-dimensional or
3-dimensional, but together with geospatial_bounds_vertical_crs, if that
attribute is supplied, must match the dimensionality, order, and meaning
of point coordinate values in the geospatial_bounds attribute. If
geospatial_bounds_vertical_crs is also present then this attribute must
only specify a 2D CRS. EPSG CRSs are strongly recommended. If this
attribute is not specified, the CRS is assumed to be EPSG:4326. Examples:
"EPSG:4979" (the 3D WGS84 CRS), "EPSG:4047”.




geospatial_bounds_vertical_crs:


The vertical coordinate reference system (CRS) for the Z axis of the point
coordinates in the geospatial_bounds attribute. This attribute cannot be
used if the CRS in geospatial_bounds_crs is 3-dimensional; to use this
attribute, geospatial_bounds_crs must exist and specify a 2D CRS. EPSG
CRSs are strongly recommended. There is no default for this attribute when
not specified. Examples: "EPSG:5829" (instantaneous height above sea
level), "EPSG:5831" (instantaneous depth below sea level), or "EPSG:5703"
(NAVD88 height).



I am not aware of any remaining issues so the above proposed definitions
are ready for the adoption vote.

	-Aleksandar