Concise Binary Object Representation (CBOR) Tag for Coordinate Reference System (CRS) SpecificationBall Aerospace and Technologies Corp.2862 Presidential Dr.Fairborn, OH45324United States+1-937-320-4000tclarke@ball.comInternet-DraftThe Concise Binary Object Representation (CBOR, RFC 7049) is a data
format whose design goals include the possibility of extremely small
code size, fairly small message size, and extensibility without the
need for version negotiation.In CBOR, one point of extensibility is the definition of CBOR tags.
An existing CBOR tag, 103, allows for the representation of geographic coordinates.
Proper exploitation of geographic coordinates requires an associated reference
frame. The present document defines a CBOR tag for referencing the coordinate
reference system (CRS) for a geographic coordinate. It is intended as the reference
document for the IANA registration of the CBOR tag defined.Specifying geographic coordinates for a location on Earth requires the definition of a coordinate reference system (CRS).
A CRS is made up of several components: Coordinate system: The X, Y grid upon which your data is overlayed and how you define where a point is located in space.Horizontal and vertical units: The units used to define the grid along the x, y (and z) axis.Datum: A modeled version of the shape of the Earth which defines the origin used to place the coordinate system in space. You will learn this further below.Projection Information: The mathematical equation used to flatten objects that are on a round surface (e.g. the Earth) so you can view them on a flat surface (e.g. your computer screens or a paper map).This document aims to address the specification of coordinate reference systems in CBOR encoded data. This is accomplished
using complete CRS specification or through a well-known spatial reference identifier.This tag is designed for use with the Geographic Coordinates CBOR Tag 103 . A CRS may be attached to a Geographic Coordinate
or it may specify a default CRS for an entire scope. This is the expected application but this tag may be used in any
relevant context.The CBOR CRS tag shall be associated with one of multiple CBOR data types. Each allowed type is associated with a
different method of specifying a CRS.OGC Well-known Text (WKT) is a standarized format for CRS specification. When the CRS tag is associated with
a Text String (CBOR Major type 3), the data shall be interpreted as OGC WKT. This allows for complete CRS specifcation of
and subtype of CRS.A spatial reference identifier (SRID) is a unique value which unambiguously identifies a CRS. Many vendors and registries
provice SRIDs. This association is not intended to allow specification of an arbitrary SRID, but provides a way to
reference an SRID in the European Pertroleum Survey Group’s (EPSG) SRID database. EPSG numbers are a de-facto standard
for CRS reference and are very commonly used. EPSG numbers can be searched and referenced in a number of places including
and . When the CRS tag is associated with a basic numeric type (CBOR Major type 0),
the data shall be interpreted as an EPSG SRID.IANA is requested to allocate a tag from the Specification Required space, with the present document as the specification reference.TagData ItemSemanticsTBDmultipleGeographic Coordinate Reference System WKT or EPSG numberRFC editor note: Please replace TBD by the tag number allocated by IANA throughout the document and delete this note.The security considerations of apply; the tag introduced here are not expected to raise security considerations beyond those.CBOR Geographic CoordinatesGeographic information - Well-known text representation of coordinate reference systemsOpen Geospatial ConsortiumConcise Binary Object Representation (CBOR)The Concise Binary Object Representation (CBOR) is a data format whose design goals include the possibility of extremely small code size, fairly small message size, and extensibility without the need for version negotiation. These design goals make it different from earlier binary serializations such as ASN.1 and MessagePack.Earthlab/Earth-Analytics-R-Course: Earth Analytics Course In The R Programming LanguageMapTiler EPSG Reference WebsiteSpatial Reference WebsiteSR-ORG:7428 WGS 84 (3D EGM96 geoid height)The Open Geospatial ConsortiumCRS for EPSG:4326, the World Geodetic System 1984 horizontal coordinate system used by GPS satellites, specified using an EPSG SRID.CRS for WGS 84 3D EGM96 geoid height specified using WKT