From 1bc21dc839dfc8aed6ac38749571fe0aa692fa51 Mon Sep 17 00:00:00 2001 From: Matthias Mohr Date: Mon, 22 May 2023 12:47:23 +0200 Subject: [PATCH] Clarifications --- crosswalks/ogcapi-processes.md | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-) diff --git a/crosswalks/ogcapi-processes.md b/crosswalks/ogcapi-processes.md index 5a507bca..b152dc6e 100644 --- a/crosswalks/ogcapi-processes.md +++ b/crosswalks/ogcapi-processes.md @@ -6,12 +6,27 @@ This document gives a brief overview over similarities and differences between In the following I use **OAP1** as an abbreviation for **OGC API - Processes - Part 1**. -## General +## Introduction OCG API - Processes defines just processing, while the openEO API has a much broader scope. openEO covers many parts that other OGC API specifications define, some are aligned some are not. +### tl;dr + +Conceptually the APIs are similar, but have some conflicts that can't be resolved easily +(e.g. process description with multiple outputs in OAP1, job listing with different job status values). + +A key differentiator between OAP1 and openEO is that process chaining is a fundamental concept in openEO +to build your own workflows while OAP1 is more meant to run larger "black box" workflows. You can add +workflows with Part 3 of OGC API - Processes. + +Another key differentiator is that openEO has a list of pre-defined but extensible processes available +while OGC API - Processes doesn't predefine processes. + +As such the target audience of OAP1 and openEO is probably only partially overlapping. + The openEO API covers the following "categories" of endpoints: + - [API discovery](#api-discovery) - partially covered by OGC API - Processes - Part 1 - [Authentication](#authentication) - not defined by OGC - [Data Discovery](#data-discovery) - covered by various other OGC APIs (Coverages, EDR, Features, Records, ...) @@ -24,6 +39,8 @@ The openEO API covers the following "categories" of endpoints: - [On-demand processing](#on-demand-processing) - covered by other OGC APIs (Maps, Tiles, ...) - [File Storage](#file-storage) - not covered by OGC APIs +## General API mechanics + Both APIs use HTTP as the basis and encourage HTTPS. HTTP 1.1 is required for OAP1, while openEO doesn't specify a specific HTTP version. The APIs follow REST principles and make use of HTTP content negotiation. @@ -132,11 +149,18 @@ and OAP1 still provides a predefined set of fields which conflict with openEO (s The openEO API specifies a single encoding for process descriptions. -An important difference is that in OAP1 you usually execute just one process +An important difference is that in OAP1 you just execute one process (you can optionally chain them using OGC API - Processes - Part 3). -This means a process in OAP1 are usually more complex. -In openEO a process is usually very fine-granular (e.g. addition of two numbers) +This means a process in OAP1 is often more complex. +In openEO a process is often very fine-granular (e.g. addition of two numbers) and you usually chain multiple of them to a more complex process (graph). +The process chaining into a full graph is fundamental in openEO. + +Another major difference is that in openEO there are +[pre-defined process descriptions available for common use cases](https://processes.openeo.org). +OGC API - Processes doesn't provide pre-defined process descriptions. +In theory, you could re-use the openEO processes in OGC API - Processes +if OGC API - Processes - Part 3 is implemented for chaining. ### Pre-defined processes