[Esip-documentation] Geospatial Bounds

[Aleksandar Jelenak via Esip-documentation]

Hello all!

The latest round of comments about the geospatial_bounds attribute
requested the flexibility in specifying the coordinate reference system.
Fine. Below are three alternative approaches:

1) New Attribute for CRS

A new attribute, geospatial_bounds_srid, will hold the EPSG code of the
CRS. Example:

geospatial_bounds = “POLYGON ((40.26 -111.29, 41.26 -111.29, 41.26
-110.29, 40.26 -110.29, 40.26 -111.29))”

geospatial_bounds_srid = 4326

The new attribute’s name could also be “geospatial_srid” to provide CRS
information for the currently CRS-less attributes like
geospatial_lat|lon_min|max.

2) Extended WKT

The EPSG code of the CRS is included in the value of the
geospatial_bounds. This is the Extended WKT format. Although the most
compact form, it is non-standard. Example:

geospatial_bounds = “SRID=4326;POLYGON ((40.26 -111.29, 41.26 -111.29,
41.26 -110.29, 40.26 -110.29, 40.26 -111.29))”

3) No CRS

Instead of specifying a CRS, several geospatial attributes — some new,
some old — specify the most relevant CRS information. For example, new
attributes like:

geospatial_bounds_x_axis ::= “latitude”  | “longitude”

geospatial_bounds_y_axis ::= “longitude” | “latitude”

with perhaps some old ones: geospatial_lat_units, geospatial_lon_units,
etc. 

Let’s agree on the most appropriate approach first and then fix the
definitions. My preference: #1 or #2.

	-Aleksandar