Internet DRAFT - draft-ietf-geojson-text-sequence
draft-ietf-geojson-text-sequence
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
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Copyright Notice
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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].
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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
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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,
<http://www.rfc-editor.org/info/rfc20>.
[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, <http://www.rfc-editor.org/info/rfc3629>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <http://www.rfc-editor.org/info/rfc7159>.
[RFC7464] Williams, N., "JavaScript Object Notation (JSON) Text
Sequences", RFC 7464, DOI 10.17487/RFC7464, February 2015,
<http://www.rfc-editor.org/info/rfc7464>.
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[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,
<http://www.rfc-editor.org/info/rfc7946>.
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
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