Mobile device users who require map/geospatial application services and operate in disconnected or limited network connectivity environments are challenged by not having open, available geospatial data to support these applications.  Further challenging mobile device users are the limited storage available and the likelihood that each map/geospatial application will require its own potentially proprietary geospatial data store.  These separate application-specific data stores may contain the same geospatial data, wasting the limited storage available, and requiring custom applications for data translation, replication, and synchronization to enable different map/geospatial applications to share the same world view.  In addition, many existing geospatial data stores are platform-specific, which means that users with different platforms must translate data to share it.

An open, standards-based, application-independent, platform-independent, self-describing, GeoPackage (GPKG) data container, API and manifest are needed to overcome these challenges and to effectively support multiple map/geospatial applications such as fixed product distribution, local data collection, and geospatially enabled analytics. This standard is intended to facilitate widespread adoption and use of GeoPackages as standard containers for “MyGeoData” by both COTS and open-source software applications on enterprise production platforms as well as mobile hand-held devices, given that mobile hand held devices do not yet have the processing power or battery life to effectively tackle difficult geospatial product production and analysis tasks.  An application that accesses a GPKG will make use of the GPKG capabilities it requires; few if any such applications will make use of all GPKG capabilities.

A future GeoPackage Web Service specification and modifications to existing OGC Web Service (OWS) specifications to use GeoPackages as exchange formats will allow OWS to support provisioning of GeoPackages throughout an enterprise or information community.

The purpose of the GeoPackage Service SWG is to produce a version 1.0.0 implementation standard.

An open standard non-proprietary platform-independent GeoPackage container for distribution and direct use of all kinds of geospatial data will increase the cross-platform interoperability of geospatial applications and web services.  Standard APIs for access and management of GeoPackage data will provide consistent query and update results across such applications and services.  Increased interoperability and result consistency will enlarge the potential market for such applications and services, particularly in resource-constrained computing environments like cell phones and tablets.  GeoPackages will become the standard containers for “MyGeoData” that are used as a transfer format by Geospatial Web Services and a storage format on personal and enterprise devices.

This SWG is focused on defining and documenting a new OGC GeoPackage candidate standard based on the specific contributions of existing work as a starting point listed in section 4.6 below.  The following topics are initially in scope. 

• Abstract Object Model (AOM) and UML representation thereof
  • Spatial reference systems
  • Geometries in 2D with or without measures
  • Still images, rasters and tiles
  • Simple Features with or without geometries
  • Simple Features with or without image attributes
  • Tile Matrix Sets
  • Metadata for the above
  • Manifest for the above
• Data encoding for the AOM
• Function API for the AOM
• Content Management for the AOM
• Data encoding / function API / content management implementation profiles
  • SQL tables, Geometry and Image BOLBs, XML documents / SQL functions / SQL triggers
• Requirement Statements
• Conformance Classes
• Abstract Test Suite

4.1    Use Cases

1. Initialize Container
2. Load Container
3. Update Container
4. Browse Container
5. Examine Container
6. Visualize Container
7. Analyze Container
8. Collect Observation

Note:  see Annex A section 2 for detailed use case descriptions. 

4.2    Justification Statement

To succeed in its aims, the OGC GeoPackage specification must address software implementation including binary storage format interoperability requirements.  Existing OGC specifications address data and service models and encodings, but none of them combine specifications for these topics and extend them into a specification for a software implementation with binary storage format interoperability requirements. 

4.3    Relationship to OGC Standards Baseline

GeoPackages facilitate sharing geospatial information.  The initial version of the GeoPackage specification will address Topic 5 - Features, and raw data and derived images from Topic 7 - The Earth Imagery Case.  The initial version will not address Topic 6 – The Coverage Type or processes for transforming raw image data into derived images. 

Note:  see Annex A section 3 for a detailed list of base OGC implementation standards.

4.4    RoadMap Plan for SWG Activities

• Select SWG Chair, Vice Chair and Specification Editor
• Revise OGC yy-nnnrx GeoPackage_OGC_Candidate_Standard.docx draft
  • Identify and address issues raised during OWS-9 testbed, but not addressed in draft document
  • Process change requests received during SWG 30 day comment period
  • Incorporate Use Cases
  • Document Abstract Object Model
  • Revise initial (SQL) implementation profile
    • Data encoding for the AOM
    • Function API for the AOM
    • Content Management for the AOM
    • Manifest for the AOM
      • Harmonization with OWS Context (OWC)
  • Revise requirement statements
  • Revise Conformance Classes
  • Document Abstract Test Suite
  • Vote for release of candidate GeoPackage standard for 30 day comment period
  • OAB and OGC-NA review
  • 30 day public comment period
  • Collect comments and edit candidate standard
  • Vote for recommend to TC/PC for adoption

4.5    What is Out of Scope?

The following activities are out of scope for the initial OGC GeoPackage specification, but may be in scope for future versions of the OGC GeoPackage specification, or other related specifications as indicated.

• GeoPackage change requests or other issues beyond those submitted during the 30 day public comment period (future or related)
• Additional raster formats (future)
• Support for Augmented Reality Markup Language (future)
• Additional (Meta)data and functions to support
  • geometries in 3D and elevation data (future)
  • coverages (future)
  • transforming raw imagery into finished data products (future)
• Encryption of GeoPackages and/or individual data subsets or items (future)
• Applications and web services for loading, provisioning, distributing, synchronizing, and using GeoPackages (related)
• Change Requests for existing OWS to use GeoPackages (related)
• Change Requests for revisions to OWS Common or OWC to support GeoPackage manifest (related)

4.6    Specific Contribution of Existing Work as a Starting Point

https://portal.opengeospatial.org/twiki/pub/OWS9/GeoPackage/GeoPackage_OGC_Candidate_Standard.pdf  draft developed by Army Geospatial Center and refined and used as the basis for developing mobile applications in the OWS-9 Innovations Thread, and Engineering Reports developed in that Thread will be used as a starting point.  The following will be used as reference material:

• Archives of discussions held on
  • ows-9-mobile [at] lists [dot] opengeospatial [dot] org
  • https://groups.google.com/forum/?hl=en&fromgroups#!forum/geospatial-mobile-data-format-for-vectors
  • https://groups.google.com/forum/?hl=en&fromgroups#!forum/geospatial-mobile-data-format-for-tiles
• Powerpoint presentation from 2011 Austin OGC TC D&I WG meeting
  • https://portal.opengeospatial.org/twiki/pub/OWS9/GeoPackage/GeoPackage.pptx

4.7    Determination of SWG Completion.

The GeoPackage SWG shall be dissolved after the following three milestones have been achieved:

1. The SWG has produced a V1.0 GeoPackage candidate standard.
2. SWG membership approves a recommendation to submit the candidate standard document to the TC for consideration as an OGC Adopted Standard.
3. The candidate standard has been approved by the OGC Technical and Planning Committees as an Adopted OGC standard.

There shall be one deliverable, a V1.0 GeoPackage Candidate Standard document.

The IPR Policy for the GeoPackage SWG will be RAND and Royalty Free.

The primary anticipated participants in this SWG include developers, vendors, and users of Geospatial Applications, Geospatial Web Services, and Geospatial Data Stores.   Other anticipated  participants include participants in current and past SWGs for OWS specifications that may be subject of future Change Requests to harmonize them with the GeoPackage specification (e.g. OWS Common and OWS Context) or to use GeoPackages as an exchange and storage format (e.g. WMS, WMTS, WFS, WCS).

Note:  see Annex A section 4 for a list of similar and applicable standards and implementations.

b. Details of the First Meeting

The first meeting of the SWG will be held by telephone conference call at 8AM EDT on 18 October 2012. Call-in information will be provided to the SWG's e-mail list and on the portal calendar in advance of the meeting.

c. Projected On-going Meeting Schedule

The work of the SWG will be carried out primarily by email and conference calls, possibly every week, with face-to-face meetings perhaps at each of the OGC TC meetings.
 
d. Supporters of the Proposal

The following people support this proposal and are committed to the Charter and projected meeting schedule. These members are known as SWG Founding or Charter members. Once the SWG is officially activated, this group is immediately “opted-into” the SWG and will have voting rights from the first day the SWG is officially formed.

 
e. Convener(s)

            Kevin Backe (U.S. Army Geospatial Center)