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Is this intentional? -- Found something which looks like a code comment -- if you have code sections in the document, please surround them with '' and '' lines. Checking references for intended status: Informational ---------------------------------------------------------------------------- ** Obsolete normative reference: RFC 7049 (Obsoleted by RFC 8949) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group T. Clarke 3 Internet-Draft BATC 4 Intended status: Informational March 22, 2019 5 Expires: September 23, 2019 7 Concise Binary Object Representation (CBOR) Tag for Coordinate Reference 8 System (CRS) Specification 9 draft-clarke-cbor-crs-00 11 Abstract 13 The Concise Binary Object Representation (CBOR, RFC 7049) is a data 14 format whose design goals include the possibility of extremely small 15 code size, fairly small message size, and extensibility without the 16 need for version negotiation. 18 In CBOR, one point of extensibility is the definition of CBOR tags. 19 An existing CBOR tag, 103, allows for the representation of 20 geographic coordinates. Proper exploitation of geographic 21 coordinates requires an associated reference frame. The present 22 document defines a CBOR tag for referencing the coordinate reference 23 system (CRS) for a geographic coordinate. It is intended as the 24 reference document for the IANA registration of the CBOR tag defined. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at https://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on September 23, 2019. 43 Copyright Notice 45 Copyright (c) 2019 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (https://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 61 2. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . 3 62 3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 3 63 4. Semantics . . . . . . . . . . . . . . . . . . . . . . . . . . 3 64 4.1. Well-known Text . . . . . . . . . . . . . . . . . . . . . 3 65 4.2. EPSG Spatial Reference Identifier . . . . . . . . . . . . 3 66 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 67 6. Security Considerations . . . . . . . . . . . . . . . . . . . 4 68 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 69 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 70 7.2. Informative References . . . . . . . . . . . . . . . . . 4 71 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 5 72 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 74 1. Introduction 76 Specifying geographic coordinates for a location on Earth requires 77 the definition of a coordinate reference system (CRS). A CRS is made 78 up of several components: [EDS1] 80 o Coordinate system: The X, Y grid upon which your data is overlayed 81 and how you define where a point is located in space. 83 o Horizontal and vertical units: The units used to define the grid 84 along the x, y (and z) axis. 86 o Datum: A modeled version of the shape of the Earth which defines 87 the origin used to place the coordinate system in space. You will 88 learn this further below. 90 o Projection Information: The mathematical equation used to flatten 91 objects that are on a round surface (e.g. the Earth) so you can 92 view them on a flat surface (e.g. your computer screens or a paper 93 map). 95 2. Objectives 97 This document aims to address the specification of coordinate 98 reference systems in CBOR [RFC7049] encoded data. This is 99 accomplished using complete CRS specification or through a well-known 100 spatial reference identifier. 102 3. Applicability 104 This tag is designed for use with the Geographic Coordinates CBOR Tag 105 103 [CBOR-GC]. A CRS may be attached to a Geographic Coordinate or 106 it may specify a default CRS for an entire scope. This is the 107 expected application but this tag may be used in any relevant 108 context. 110 4. Semantics 112 The CBOR CRS tag shall be associated with one of multiple CBOR data 113 types. Each allowed type is associated with a different method of 114 specifying a CRS. 116 4.1. Well-known Text 118 OGC [OGC] Well-known Text (WKT) [WKT] is a standarized format for CRS 119 specification. When the CRS tag is associated with a Text String 120 (CBOR Major type 3), the data shall be interpreted as OGC WKT. This 121 allows for complete CRS specifcation of and subtype of CRS. 123 4.2. EPSG Spatial Reference Identifier 125 A spatial reference identifier (SRID) is a unique value which 126 unambiguously identifies a CRS. Many vendors and registries provice 127 SRIDs. This association is not intended to allow specification of an 128 arbitrary SRID, but provides a way to reference an SRID in the 129 European Pertroleum Survey Group's (EPSG) SRID database. EPSG 130 numbers are a de-facto standard for CRS reference and are very 131 commonly used. EPSG numbers can be searched and referenced in a 132 number of places including [EPSG.io] and [SpatialReference.org]. 133 When the CRS tag is associated with a basic numeric type (CBOR Major 134 type 0), the data shall be interpreted as an EPSG SRID. 136 5. IANA Considerations 138 IANA is requested to allocate a tag from the Specification Required 139 space, with the present document as the specification reference. 141 +-----+----------+--------------------------------------------------+ 142 | Tag | Data | Semantics | 143 | | Item | | 144 +-----+----------+--------------------------------------------------+ 145 | TBD | multiple | Geographic Coordinate Reference System WKT or | 146 | | | EPSG number | 147 +-----+----------+--------------------------------------------------+ 149 *RFC editor note*: Please replace TBD by the tag number allocated by 150 IANA throughout the document and delete this note. 152 6. Security Considerations 154 The security considerations of [RFC7049] apply; the tag introduced 155 here are not expected to raise security considerations beyond those. 157 7. References 159 7.1. Normative References 161 [CBOR-GC] "CBOR Geographic Coordinates", n.d., 162 . 165 [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object 166 Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, 167 October 2013, . 169 [WKT] Open Geospatial Consortium, "Geographic information - 170 Well-known text representation of coordinate reference 171 systems", May 2015, 172 . 174 7.2. Informative References 176 [EDS1] Wasser, L., "Earthlab/Earth-Analytics-R-Course: Earth 177 Analytics Course In The R Programming Language", 178 Zenodo article, DOI 10.5281/zenodo.1326873, August 2018. 180 [EPSG.io] "MapTiler EPSG Reference Website", n.d., 181 . 183 [OGC] "The Open Geospatial Consortium", n.d., 184 . 186 [SpatialReference.org] 187 "Spatial Reference Website", n.d., 188 . 190 [SR-ORG-7428] 191 "SR-ORG:7428 WGS 84 (3D EGM96 geoid height)", n.d., 192 . 194 Appendix A. Examples 196 CRS for EPSG:4326, the World Geodetic System 1984 horizontal 197 coordinate system used by GPS satellites, specified using an EPSG 198 SRID. 200 D8 68 # Geographic Coordinate System - tag(104) 201 19 10E6 # EPSG:4326 - unsigned(4326) 203 # Diagnostic notation: 104(4326) 205 CRS for WGS 84 3D EGM96 geoid height [SR-ORG-7428] specified using 206 WKT 207 D8 68 # Geographic Coordinate System - tag(104) 208 79 0191 # OGC WKT - text(401) 209 47454F4743535B225747532038342028 210 33442045474D39362067656F69642068 211 656967687429222C444154554D5B2257 212 6F726C642047656F6465746963205379 213 7374656D2031393834222C5350484552 214 4F49445B22574753203834222C363337 215 383133372E302C3239382E3235373232 216 333536332C415554484F524954595B22 217 45505347222C2237303330225D5D2C41 218 5554484F524954595B2245505347222C 219 2236333236225D5D2C5052494D454D5B 220 22477265656E77696368222C302E302C 221 415554484F524954595B224550534722 222 2C2238393031225D5D2C554E49545B22 223 444D53222C302E303030303034383438 224 31333638313130393533365D2C415849 225 535B2247656F6465746963206C617469 226 74756465222C4E4F5254485D2C415849 227 535B2247656F6465746963206C6F6E67 228 6974756465222C454153545D2C415849 229 535B22477261766974792D72656C6174 230 656420686569676874222C55502C4155 231 54484F524954595B2245505347222C22 232 35373733225D5D2C415554484F524954 233 595B2245505347222C2234333239225D5D 235 # Diagnostic notation: 236 104("GEOGCS[\"WGS 84 (3D EGM96 geoid height)\", 237 DATUM[\"World Geodetic System 1984\", 238 SPHEROID[\"WGS 84\",6378137.0,298.257223563, 239 AUTHORITY[\"EPSG\",\"7030\"]], 240 AUTHORITY[\"EPSG\",\"6326\"]], 241 PRIMEM[\"Greenwich\",0.0,AUTHORITY[\"EPSG\",\"8901\"]], 242 UNIT[\"DMS\",0.00000484813681109536], 243 AXIS[\"Geodetic latitude\",NORTH], 244 AXIS[\"Geodetic longitude\",EAST], 245 AXIS[\"Gravity-related height\",UP, 246 AUTHORITY[\"EPSG\",\"5773\"]], 247 AUTHORITY[\"EPSG\",\"4329\"]]") 249 Author's Address 250 Trevor R.H. Clarke 251 Ball Aerospace and Technologies Corp. 252 2862 Presidential Dr. 253 Fairborn, OH 45324 254 United States 256 Phone: +1-937-320-4000 257 Email: tclarke@ball.com