[Requests] comments:OGC GeoPackage Implementation Standard (GPKG) (12-128r1)

Norman Barker norman at cloudant.com
Mon Feb 4 11:53:31 EST 2013


PART A

1. Evaluator:
     Norman Barker, Cloudant.
     email: norman at cloudant.com

2. Submission:

OGC GeoPackage Implementation Standard (GPKG) (12-128r1)

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PART B

1. Requirement: Core, #2

2. Implementation Specification Section number: 6.1 Capabilities

3. Criticality:  Major

4. Comments/justifications for changes:

This format is specified as a SQLite database which will require a 
import for all other databases (IndexedDB, TouchDB etc). A mobile device 
may not have sufficient resources (memory and storage) to transcode that 
file format on the device and the file will either have to be converted 
before download or (slower) adapters to read the format for other 
databases will be required.

An additional requirement that Cloudant recommends to assist with this 
issue is;

Req 2i. The Geopackage shall in the future support incremental updates 
using a streaming protocol (synchronisation). For example this protocol 
can be JSON over HTTP(S) for features or a cache for web tiles.

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1. Requirement: Core, #3

2. Implementation Specification Section number: 6.1 Capabilities

3. Criticality:  Major

4. Comments/justifications for changes:

In a disconnected environment a model of eventual consistency with 
multi-version concurrency control is another valid approach. Cloudant 
ask that this requirement be removed as it is potentially confusing when 
synchronisation is supported in the specification

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1. Requirement: General

2. Implementation Specification Section number: 6.1, p. 37

3. Criticality: Minor

4. Comments/justifications for changes: [Comments]

GeoPackage container conformance with current ISO/IEC 9075 (SQL) 
standards [3][4][5][6][7] would be optimal, but at a minimum the 
GeoPackage container shall support SQL-92 [2], this seems to deviate 
from other OGC specifications that recommend clients and servers support 
Common Query Language (CQL). There is overlap with SQL, but CQL is a 
defined BNF grammar within existing OGC specifications and it would 
provider greater interoperability if this specification followed 
existing OGC standards.

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1. Requirement: Core, #7

2. Implementation Specification Section number: 6.1 Capabilities

3. Criticality:  Major

4. Comments/justifications for changes:

This is an implementation requirement and should not be required.


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1. Requirement: Core, #10

2. Implementation Specification Section number: 6.2 Reference 
implementation

3. Criticality:  Minor

4. Comments/justifications for changes:

See recommendation Req 2i above that an additional streaming 
synchronisation protocol be defined.


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1. Requirement: General

2. Implementation Specification Section number: 7. Table Diagram

3. Criticality:  Minor

4. Comments/justifications for changes:

Recommend that this diagram be a UML diagram so that a GeoJSON model can 
be defined in addition to a relational SQLite model.

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1. Requirement: General

2. Implementation Specification Section number: 13.3 Manifest XML Schema

3. Criticality:  Minor

4. Comments/justifications for changes:

Recommend that a GeoJSON example be defined in addition to XML to 
support common web/mobile use cases. These may require a JSON profile of 
the OWS Context document.


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