GeoJSON S. Gillies Internet-Draft Mapbox Intended status: Standards Track February 17, 2017 Expires: August 21, 2017 GeoJSON Text Sequences draft-ietf-geojson-text-sequence-05 Abstract This document describes the GeoJSON text sequence format and "application/geo+json-seq" media type. This format is based on JavaScript Object Notation (JSON) Text Sequences and GeoJSON, and makes arbitrarily large geographic datasets incrementally parseable without restricting the form of GeoJSON texts within a sequence. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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Gillies Expires August 21, 2017 [Page 1] Internet-Draft GeoJSONSeq February 2017 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. GeoJSON Text Sequence Format . . . . . . . . . . . . . . . . 2 3. Security Considerations . . . . . . . . . . . . . . . . . . . 3 4. Interoperability Considerations . . . . . . . . . . . . . . . 3 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.1. Normative References . . . . . . . . . . . . . . . . . . 4 6.2. Informative References . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction Arbitrarily large sequences of values pose a problem for JavaScript Object Notation (JSON) [RFC7159] that is well explained in the motivation for JSON Text Sequences [RFC7464]. The GeoJSON format [RFC7946] faces the same kind of problem. Geographic datasets often run to the tens of thousands or millions of features. The problem is often amplified by the presence of large arrays of coordinates for each of the features. This document describes a specialization of JSON Text Sequences. A GeoJSON Text Sequence is a document of arbitrarily large size containing one or more GeoJSON objects, e.g., multiple GeoJSON texts that can be produced and parsed incrementally, and not only a single GeoJSON FeatureCollection, Feature, or Geometry. 1.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. GeoJSON Text Sequence Format Defined in prose, following [RFC7464]: a GeoJSON text sequence is any number of GeoJSON [RFC7946] texts, each encoded in UTF-8 [RFC3629], each preceded by one ASCII [RFC20] RS character, and each followed by a line feed (LF). The GeoJSON Text Sequence Format conforms to all the rules of [RFC7464] and adds the following constraint: each JSON text MUST contain a single GeoJSON object as defined in [RFC7946]. Gillies Expires August 21, 2017 [Page 2] Internet-Draft GeoJSONSeq February 2017 Heterogeneous sequences containing a mix of GeoJSON Geometry, Feature, and FeatureCollection objects are permitted. How producers and parsers of GeoJSON text sequences communicate rules for allowed GeoJSON types in exchanged sequences is not specified in this document. 3. Security Considerations GeoJSON text sequences have no security considerations beyond those of JSON text sequences and the GeoJSON format. 4. Interoperability Considerations The advantage of using ASCII character RS "0x1e" to denote a text is that sequence producers and parsers need not enforce a canonical form of GeoJSON. Any valid GeoJSON, pretty-printed or compact, can be used in a GeoJSON text sequence. A variety of parsers designed for newline-delimited sequences of compact JSON text are deployed on the internet today. While there is no canonical form for JSON texts, and pretty-printed and compact forms are equally valid, GeoJSON text sequences containing compact GeoJSON texts with no internal newlines are more interoperable with existing non-standardized parsers. In a distributed system where order and exactly-once delivery of messages are difficult to achieve, GeoJSON text sequences that do not rely on order of texts for extra semantics are more interoperable than those that do. 5. IANA Considerations The MIME media type for GeoJSON feature sequences is "application/ geo+json-seq". This uses the suffix established in [I-D.wilde-json-seq-suffix]. Type name: application Subtype name: geo+json-seq Required parameters: n/a Optional parameters: n/a Encoding considerations: binary Security considerations: See [[This document]] Section 3 Gillies Expires August 21, 2017 [Page 3] Internet-Draft GeoJSONSeq February 2017 Interoperability considerations: See [[This document]] Section 4 Published specification: [[This document]] Applications that use this media type: No known applications currently use this media type. This media type is intended for GeoJSON applications currently using colloquial line-delimited variants of GeoJSON. Additional information: Magic number(s): n/a File extension(s): n/a Macintosh file type code: n/a Object Identifiers: n/a Person to contact for further information: Sean Gillies (sean.gillies@gmail.com) Intended usage: COMMON Restrictions on usage: none 6. References 6.1. Normative References [RFC0020] Cerf, V., "ASCII format for network interchange", STD 80, RFC 20, DOI 10.17487/RFC0020, October 1969, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 2003, . [RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March 2014, . [RFC7464] Williams, N., "JavaScript Object Notation (JSON) Text Sequences", RFC 7464, DOI 10.17487/RFC7464, February 2015, . Gillies Expires August 21, 2017 [Page 4] Internet-Draft GeoJSONSeq February 2017 [RFC7946] Butler, H., Daly, M., Doyle, A., Gillies, S., Hagen, S., and T. Schaub, "The GeoJSON Format", RFC 7946, DOI 10.17487/RFC7946, August 2016, . 6.2. Informative References [I-D.wilde-json-seq-suffix] Wilde, E., "A Media Type Structured Syntax Suffix for JSON Text Sequences", December 2016. Author's Address S. Gillies Mapbox Email: sean.gillies@gmail.com URI: http://sgillies.net Gillies Expires August 21, 2017 [Page 5]