GeoPackage 1.0 Extension

DRAFT

Extension follows template from Annex I of the OGC GeoPackage 1.0 Specification.

Extension Title

GeoPackage OWC specification

Introduction

The main goal of the extension is to store context and styling of a mapping project as part of a GeoPackage file containing the data it refers to.

Approach: Table owc_context stores one or multiple OWS Context files that defines a set of layers on a set of data tables using certain styles. Each layer is encoded in an ows:entry element; each style is encoded whithin the layer, as a ows:offering, in the owc:styleSet element. Any data table or style can be referenced by a layer in an OWS Context multiple times. Table owc_style defines which styles are available. Resources from owc_resources can be referenced from metadata, styles or context, to enable inclusion of images, pdf, fonts etc.

OWS Context 1.0 defines the capability to reference layers from OWS services and certain filetypes (gml/kml). In this extension we introduce the capability in OWS context to reference tables local to the Geopackage.

The OWS Context specification is extended with an offeringtype="gpkg" and OWS-context is extended to support referencing resources local to the Geopackage by using #table={table}[&{fieldname}={value}].

<owc:offering code="http://www.opengis.net/spec/owc-atom/1.0/req/gpkg">
  <owc:content type="application/x-sqlite" href="#table=MyPoints" />
  <owc:styleSet>
    <owc:name>simple_point</owc:name>
    <owc:title>Simple point</owc:title>
    <owc:content href="#table=owc_style&amp;name=simplePoint" type="application/sld+xml"/>
  </owc:styleSet>
</owc:offering>

OWC offering MUST include a styleSet reference, referencing an external SLD file or an SLD from the owc_style table.

Extension Author

Paul van Genuchten, Joana Simoes.

Extension Name or Template

owc

Extension Type

Extension of concepts

Applicability

This extension applies to additional tables owc_context, owc_resources, owc_style.

Scope

Read-write

Requirements

GeoPackage

Extension tables

An Extended GeoPackage with Context support MAY contain the following tables or views:

owc_context

Column	type	Description
name	varchar(30) unique	Context name
abstract	text	Context abstract
author	text	Comma separated list of authors
language	text	based on RFC-3066 code
mime_type	text NOT NULL	mime type of context (application/atom+xml / application/json / application/vnd.owc+xml)
content	text NOT NULL	Content of OWS_Context encoded as indicated in `mime_type`

owc_style

Column	type	Description
name	varchar(30) *
abstract	text
mime_type	varchar(30) *	The mime type of the style ( application/vnd.sld+xml / text/css / application/json)
content	text NOT NULL	Content of the style encoded as indicated in `mime_type`

A unique index of name and mime_type allows clients to select the most optimal mime-type for rendering (some mime-types may support additional vendor parameters). It is recommended to at least provide one style as appliction/vnd.sld+xml.

owc_resource

Column	type	Description
name	varchar(30) unique	Name of resource (file name)
mime_type	text NOT NULL	The mime type of the resource (image/png, application/pdf, ...)
content	blob NOT NULL	Binary content of resource

GeoPackage SQLite Configuration

None

GeoPackage SQLite Extension