Publication Date: 2021-11-29

Approval Date: 2021-11-18

Submission Date: 2021-08-13

Reference number of this document: OGC 21-055

Reference URL for this document: http://www.opengis.net/doc/PER/202107APISprintER

Category: OGC Public Engineering Report

Editor: Gobe Hobona, Joana Simoes

Title: July 2021 OGC API Code Sprint Summary Engineering Report


OGC Public Engineering Report

COPYRIGHT

Copyright © 2021 Open Geospatial Consortium. To obtain additional rights of use, visit http://www.opengeospatial.org/

WARNING

This document is not an OGC Standard. This document is an OGC Public Engineering Report created as a deliverable in an OGC Interoperability Initiative and is not an official position of the OGC membership. It is distributed for review and comment. It is subject to change without notice and may not be referred to as an OGC Standard. Further, any OGC Public Engineering Report should not be referenced as required or mandatory technology in procurements. However, the discussions in this document could very well lead to the definition of an OGC Standard.

LICENSE AGREEMENT

Permission is hereby granted by the Open Geospatial Consortium, ("Licensor"), free of charge and subject to the terms set forth below, to any person obtaining a copy of this Intellectual Property and any associated documentation, to deal in the Intellectual Property without restriction (except as set forth below), including without limitation the rights to implement, use, copy, modify, merge, publish, distribute, and/or sublicense copies of the Intellectual Property, and to permit persons to whom the Intellectual Property is furnished to do so, provided that all copyright notices on the intellectual property are retained intact and that each person to whom the Intellectual Property is furnished agrees to the terms of this Agreement.

If you modify the Intellectual Property, all copies of the modified Intellectual Property must include, in addition to the above copyright notice, a notice that the Intellectual Property includes modifications that have not been approved or adopted by LICENSOR.

THIS LICENSE IS A COPYRIGHT LICENSE ONLY, AND DOES NOT CONVEY ANY RIGHTS UNDER ANY PATENTS THAT MAY BE IN FORCE ANYWHERE IN THE WORLD. THE INTELLECTUAL PROPERTY IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE DO NOT WARRANT THAT THE FUNCTIONS CONTAINED IN THE INTELLECTUAL PROPERTY WILL MEET YOUR REQUIREMENTS OR THAT THE OPERATION OF THE INTELLECTUAL PROPERTY WILL BE UNINTERRUPTED OR ERROR FREE. ANY USE OF THE INTELLECTUAL PROPERTY SHALL BE MADE ENTIRELY AT THE USER’S OWN RISK. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR ANY CONTRIBUTOR OF INTELLECTUAL PROPERTY RIGHTS TO THE INTELLECTUAL PROPERTY BE LIABLE FOR ANY CLAIM, OR ANY DIRECT, SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM ANY ALLEGED INFRINGEMENT OR ANY LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR UNDER ANY OTHER LEGAL THEORY, ARISING OUT OF OR IN CONNECTION WITH THE IMPLEMENTATION, USE, COMMERCIALIZATION OR PERFORMANCE OF THIS INTELLECTUAL PROPERTY.

This license is effective until terminated. You may terminate it at any time by destroying the Intellectual Property together with all copies in any form. The license will also terminate if you fail to comply with any term or condition of this Agreement. Except as provided in the following sentence, no such termination of this license shall require the termination of any third party end-user sublicense to the Intellectual Property which is in force as of the date of notice of such termination. In addition, should the Intellectual Property, or the operation of the Intellectual Property, infringe, or in LICENSOR’s sole opinion be likely to infringe, any patent, copyright, trademark or other right of a third party, you agree that LICENSOR, in its sole discretion, may terminate this license without any compensation or liability to you, your licensees or any other party. You agree upon termination of any kind to destroy or cause to be destroyed the Intellectual Property together with all copies in any form, whether held by you or by any third party.

Except as contained in this notice, the name of LICENSOR or of any other holder of a copyright in all or part of the Intellectual Property shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Intellectual Property without prior written authorization of LICENSOR or such copyright holder. LICENSOR is and shall at all times be the sole entity that may authorize you or any third party to use certification marks, trademarks or other special designations to indicate compliance with any LICENSOR standards or specifications.

This Agreement is governed by the laws of the Commonwealth of Massachusetts. The application to this Agreement of the United Nations Convention on Contracts for the International Sale of Goods is hereby expressly excluded. In the event any provision of this Agreement shall be deemed unenforceable, void or invalid, such provision shall be modified so as to make it valid and enforceable, and as so modified the entire Agreement shall remain in full force and effect. No decision, action or inaction by LICENSOR shall be construed to be a waiver of any rights or remedies available to it.

None of the Intellectual Property or underlying information or technology may be downloaded or otherwise exported or reexported in violation of U.S. export laws and regulations. In addition, you are responsible for complying with any local laws in your jurisdiction which may impact your right to import, export or use the Intellectual Property, and you represent that you have complied with any regulations or registration procedures required by applicable law to make this license enforceable.

Table of Contents

1. Subject

The subject of this Engineering Report (ER) is a virtual code sprint that was held from July 21st to July 23rd, 2021 to advance the development of the OGC API - Processes draft standard, OGC API - Records draft standard, and the OGC API – Coverages draft standard. An Application Programming Interface (API) is a standard set of documented and supported functions and procedures that expose the capabilities or data of an operating system, application or service to other applications (adapted from ISO/IEC TR 13066-2:2016).

2. Executive Summary

This Engineering Report (ER) summarizes the main achievements of the July 2021 OGC API Virtual Code Sprint, conducted from July 21st to July 23rd. The goal of the code sprint was to progress the development of the draft OGC API standards for Records, Coverages and Processes. The sprint served to accelerate development of candidate standards of the OGC APIs.

Specifically, the objectives of the code sprint were to:

  • Develop prototype implementations of OGC API – Processes

  • Develop prototype implementations of OGC API – Records

  • Develop prototype implementations of OGC API – Coverages

  • Test the prototype implementations

  • Provide feedback to the Editor about what worked and what did not work

  • Provide feedback about the specification document, especially what is missing from the document

Part of the motivation for holding the sprint was:

  • APIs are a popular, effective method for rapid software development

  • There is an increasing need for interoperability between Web APIs

  • The growing uptake of location within and outside of geospatial developer communities

The draft OGC API - Processes specification defines an interface that enables the execution of geospatial computing processes and the retrieval of metadata describing their purpose and functionality. Typically, these processes execute well-defined algorithms that ingest vector and/or coverage data to produce new datasets.

The draft OGC API - Records specification defines an interface that enables discovery and access to metadata records about resources such as features, coverages, tiles / maps, models, assets, services or widgets. The draft specification enables the discovery of geospatial resources by standardizing the way collections of descriptive information about the resources (metadata) are exposed and accessed.

The draft OGC API - Coverages specification defines an interface that enables access to coverages that are modeled according to the Coverage Implementation Schema (CIS) 1.1. Coverages are represented by some binary or ASCII serialization, specified by some data (en­coding) format. Arguably the most popular type of coverage is that of a gridded coverage. Gridded coverages have a grid as their domain set describing the direct positions in multi-dimensional coordinate space, depending on the type of grid. Satellite imagery is typically modeled as a gridded coverage, for example.

The code sprint successfully met all of its objectives and achieved its goal of progressing the development of the OGC API - Processes draft standard, OGC API - Records draft standard, and the OGC API – Coverages draft standard. There were no issues found on the Processes API, which helped to validate the maturity and stability of the API. Discussion about the Records API helped to improve understanding of the potential relationship to other related specifications (e.g. STAC and ISO 19115). Issues raised relating to the Coverages API were focused around clarification, thereby identifying areas where the documentation could be improved. The sprint participants demonstrated that the OGC API pattern can effectively address the needs of communities that use, process and analyze geospatial data.

2.1. Document contributor contact points

All questions regarding this document should be directed to the editor or the contributors:

Contacts

Name Organization Role

Gobe Hobona

OGC

Editor

Joana Simoes

OGC

Editor

Adrian Akbari

adrianakbari

Contributor

Adrian Cochrane

OpenWork Ltd

Contributor

Amy Youmans

AGC

Contributor

Andrea Aime

GeoSolutions

Contributor

Angelos Tzotsos

Open Source Geospatial Foundation

Contributor

Benjamin Pross

52°North GmbH

Contributor

Bradford Dean

Mohawk Council of Kahnawake

Contributor

Brian Hamlin

Open Source Geospatial Foundation

Contributor

Byron Cochrane

OpenWork Ltd

Contributor

Chris Holmes

Planet

Contributor

Clemens Portele

interactive instruments

Contributor

Colin Steinmann

Ethar Inc

Contributor

Diego Caraffini

Ecere co.

Contributor

Eike Hinderk Jürrens

52°North Spatial Information Research GmbH

Contributor

Fabio Govoni

MEEO

Contributor

Francesco  Bartoli 

Geobeyond 

Contributor

Gérald Fenoy

GeoLabs

Contributor

Gladys Villegas

Ghent University

Contributor

Iain Burnell

Dstl

Contributor

Ingrid Lagares

UFMG

Contributor

Jeff Harrison

AGC

Contributor

Jerome St-Louis

Ecere

Contributor

John Ferry

Trenchant Analytics

Contributor

Mario Cavicchi

MEEO

Contributor

Martin Pontius

52°North Spatial Information Research GmbH

Contributor

Nazih Fino

Global Nomad GIS Services

Contributor

Panagiotis Vretanos

CubeWerx Inc.

Contributor

Patrick Dion

Ecere Corporation

Contributor

Paul van Genuchten

GeoCat BV

Contributor

Philippe Pinheiro

LIST

Contributor

Richard Conway

Telespazio UK Ltd

Contributor

Rob Emanuele

Microsoft

Contributor

Roger Brackin

Envitia

Contributor

Stephan Meißl

EOX

Contributor

Steven McDaniel

Hexagon Geospatial

Contributor

Tom Kralidis

Meteorological Service of Canada

Contributor

2.2. Foreword

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The Open Geospatial Consortium shall not be held responsible for identifying any or all such patent rights.

Recipients of this document are requested to submit, with their comments, notification of any relevant patent claims or other intellectual property rights of which they may be aware that might be infringed by any implementation of the standard set forth in this document, and to provide supporting documentation.

3. References

4. Terms and definitions

For the purposes of this report, the definitions specified in Clause 4 of the OWS Common Implementation Standard OGC 06-121r9 shall apply. In addition, the following terms and definitions apply.

● coordinate reference system

coordinate system that is related to the real world by a datum term name (source: ISO 19111)

● coverage

feature that acts as a function to return values from its range for any direct position within its spatiotemporal domain, as defined in OGC Abstract Topic 6

● record

atomic unit of information of a catalogue that is used to provide information about a particular resource

● OpenAPI Document

A document (or set of documents) that defines or describes an API. An OpenAPI definition uses and conforms to the OpenAPI Specification (https://www.openapis.org)

● Web API

API using an architectural style that is founded on the technologies of the Web [source: OGC API - Features - Part 1: Core]

Note
See Best Practice 24: Use Web Standards as the foundation of APIs (W3C Data on the Web Best Practices) for more detail.

4.1. Abbreviated terms

  • API Application Programming Interface

  • CORS Cross-Origin Resource Sharing

  • OGC Open Geospatial Consortium

5. Introduction

This Engineering Report (ER) summarizes the main achievements of the July 2021 OGC API Virtual Code Sprint, conducted from July 21st to July 23rd. The sprint had been organized to advance the development of draft standards of OGC APIs for Records, Coverages and Processes. Sprint participants prototyped implementations of the draft standards, validating the requirements and providing feedback so that the draft standards could be improved.

An OGC Code Sprint is a collaborative and inclusive event driven by innovative and rapid programming with minimal process and organization constraints to support the development of new applications and open standards. OGC Code Sprints experiment with emerging ideas in the context of geospatial standards, help improve interoperability of existing standards by experimenting with new extensions or profiles, and are used for building proofs of concept for other OGC Innovation Program initiatives, or to support OGC Standards Program activities.

6. High-Level Architecture

6.1. High Level Overview

The code sprint was executed in support of the development of the draft OGC API - Records, OGC API - Processes and OGC API - Coverages standards. Implementations of these draft standards were deployed in participants' own infrastructure in order to build a solution with the architecture shown below in Figure 1.

architecture
Figure 1. High level overview of the architecture implemented during the sprint

As illustrated, the sprint architecture was designed with the view of enabling client applications to connect to different servers that implement OGC APIs. The servers were provisioned with metadata, implementations of algorithms for geospatial analysis, vector feature data, and coverages such as satellite imagery.

6.2. Candidate Standards

6.2.1. OGC API - Processes

The draft OGC API - Processes specification defines an interface that enables the execution of geospatial computing processes and the retrieval of metadata describing their purpose and functionality. Typically, these processes execute implementations of well-defined algorithms that ingest vector and/or coverage data to produce new datasets or analytical products.

6.2.2. OGC API - Records

The draft OGC API - Records specification defines an interface that enables discovery and access to metadata records about resources such as features, coverages, tiles / maps, models, assets, services or widgets. The draft specification enables the discovery of geospatial resources by standardizing the way collections of descriptive information about the resources (metadata) are exposed and accessed.

6.2.3. OGC API - Coverages

The draft OGC API - Coverages specification defines an interface that enables access to coverages that are modeled according to the Coverage Implementation Schema (CIS) 1.1. Coverages are represented by some binary or ASCII serialization, specified by some data (en­coding) format. Arguably the most popular type of coverage is that of a gridded coverage. Gridded coverages have a grid as their domain set describing the direct positions in multi-dimensional coordinate space, depending on the type of grid. Satellite imagery is typically modeled as a gridded coverage, for example.

7. Results

Multiple organizations provided servers, API implementations, and capabilities during the event. The rest of this section describes each of the implementations.

7.1. Augmented Reality Application

Developers from Ethar Inc and Global Nomad took part in the code sprint, extending an Augmented Reality (AR) application that they are building for Testbed-17. The AR application, which runs on a smartphone, allows a coverage such as one representing a Digital Elevation Model (DEM), to be visualized in a three-dimensional AR view as shown in Figure 2. This facilitates 'tabletop' visualization so that a group of people could potentially stand around a table and see geographic representation superimposed onto that table, with the DEM viewed either through smart glasses or a smartphone. The AR application can ingest coverages encoded in GeoTIFF format, therefore the application could be served by an implementation of OGC API - Coverages.