{"id":5120,"date":"2018-04-17T15:15:22","date_gmt":"2018-04-17T14:15:22","guid":{"rendered":"https:\/\/wip.geomatys.com\/?p=5120"},"modified":"2025-07-04T10:43:01","modified_gmt":"2025-07-04T09:43:01","slug":"quels-standards-ogc-pour-linformatique-en-nuage","status":"publish","type":"post","link":"https:\/\/www.geomatys.com\/en\/2018\/04\/17\/quels-standards-ogc-pour-linformatique-en-nuage\/","title":{"rendered":"Quels standards OGC pour l\u2019informatique en nuage\u00a0?"},"content":{"rendered":"<div data-elementor-type=\"wp-post\" data-elementor-id=\"5120\" class=\"elementor elementor-5120\" data-elementor-settings=\"{&quot;ha_cmc_init_switcher&quot;:&quot;no&quot;}\">\n\t\t\t\t\t\t<section class=\"has_eae_slider elementor-section elementor-top-section elementor-element elementor-element-1bfe1962 elementor-section-full_width elementor-section-height-default elementor-section-height-default exad-glass-effect-no wpr-particle-no wpr-jarallax-no wpr-parallax-no wpr-sticky-section-no 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class=\"trp-ls-language-name\">FR<\/span><\/span><\/a><\/li>\n<\/ul><\/div><\/nav>\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"has_eae_slider elementor-column elementor-col-33 elementor-top-column elementor-element elementor-element-5cd25c2 exad-glass-effect-no exad-sticky-section-no\" data-eae-slider=\"8648\" data-id=\"5cd25c2\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap\">\n\t\t\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t<div class=\"has_eae_slider elementor-element elementor-element-39cab68c e-flex e-con-boxed wpr-particle-no wpr-jarallax-no wpr-parallax-no wpr-sticky-section-no wpr-equal-height-no e-con e-parent\" data-eae-slider=\"77196\" data-id=\"39cab68c\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-1afad8fd exad-sticky-section-no exad-glass-effect-no elementor-widget elementor-widget-heading\" data-id=\"1afad8fd\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h1 class=\"elementor-heading-title elementor-size-default\">Quels standards OGC pour l'informatique en nuages ?<\/h1>\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"has_eae_slider elementor-element elementor-element-c4580a6 e-flex e-con-boxed wpr-particle-no wpr-jarallax-no wpr-parallax-no wpr-sticky-section-no wpr-equal-height-no e-con e-parent\" data-eae-slider=\"22313\" data-id=\"c4580a6\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-6d6da7dc wpr-post-info-align-left exad-sticky-section-no exad-glass-effect-no elementor-widget elementor-widget-wpr-post-info\" data-id=\"6d6da7dc\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"wpr-post-info.default\">\n\t\t\t\t\t<ul class=\"wpr-post-info wpr-post-info-horizontal\"><li class=\"wpr-post-info-date\"><span>17\/04\/2018<\/span><\/li><li class=\"wpr-post-info-author\"><span>Martin Desruisseaux<\/span><\/li><\/ul>\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"has_eae_slider elementor-element elementor-element-a60291e e-flex e-con-boxed wpr-particle-no wpr-jarallax-no wpr-parallax-no wpr-sticky-section-no wpr-equal-height-no e-con e-parent\" data-eae-slider=\"92827\" data-id=\"a60291e\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-2cd3e31c exad-sticky-section-no exad-glass-effect-no elementor-widget elementor-widget-text-editor\" data-id=\"2cd3e31c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p><\/p>\n<p>Les membres du consortium Open Geospatial (OGC) se sont r\u00e9unis \u00e0 Orl\u00e9ans du 19 au 23 mars. Depuis peu, ces r\u00e9unions exp\u00e9rimentent une nouvelle formule pour la s\u00e9ance pl\u00e9ni\u00e8re de cl\u00f4ture. Durant la semaine, les membres votent pour un sujet qui sera pr\u00e9sent\u00e9 et d\u00e9battu en s\u00e9ance.\u00a0\u00c0 Orl\u00e9ans, le sujet discut\u00e9 \u00e0 la cl\u00f4ture \u00e9tait latent depuis plusieurs mois. Il avait \u00e9t\u00e9 soulev\u00e9 plus explicitement, sous diff\u00e9rentes formes, \u00e0 au moins deux reprises au cours de la semaine.<\/p>\n<p><\/p>\n<p><\/p>\n<p>Depuis une ou deux ann\u00e9es, les agences spatiales \u2013 notamment la NASA et l\u2019ESA \u2013 expriment \u00e0 l\u2019OGC un besoin d\u2019inverser la logique actuelle dans la fa\u00e7on de manipuler les donn\u00e9es. Au lieu d\u2019amener les donn\u00e9es aux algorithmes (c\u2019est-\u00e0-dire de t\u00e9l\u00e9charger des donn\u00e9es \u00e0 partir de serveurs vers le poste du scientifique qui effectuera les calculs), on souhaite amener les algorithmes vers les donn\u00e9es. La raison est que les donn\u00e9es d\u2019observation de la Terre occupent un volume tel que leur t\u00e9l\u00e9chargement peut devenir impraticable. On souhaite plut\u00f4t ex\u00e9cuter les algorithmes l\u00e0 o\u00f9 se trouvent les donn\u00e9es.<\/p>\n<p><\/p>\n<p><\/p>\n<p>Ce souhait est d\u00e9j\u00e0 partiellement r\u00e9alis\u00e9 par certains acteurs. Par exemple Google Earth Engine (GEE) permet d\u2019ex\u00e9cuter des algorithmes d\u00e9finis par l\u2019utilisateur sur les serveurs de Google. Le\u00a0<a href=\"https:\/\/developers.google.com\/earth-engine\/getstarted#mapping-what-to-do-instead-of-a-for-loop\">guide du d\u00e9veloppeur<\/a>\u00a0contient un exemple d\u2019algorithme (un calcul d\u2019indice de v\u00e9g\u00e9tation) ex\u00e9cut\u00e9 localement, puis ex\u00e9cut\u00e9 plus efficacement sur les serveurs o\u00f9 se trouvent les donn\u00e9es. Mais cet exemple utilise une interface de programmation (API) propre \u00e0 Google\u00a0; aucun standard g\u00e9ospatial n\u2019y est appliqu\u00e9. Cette conception expose les utilisateurs au risque de verrouillage du fournisseur. Une situation o\u00f9 les algorithmes \u00e9crits pour GEE peuvent \u00eatre difficiles \u00e0 porter vers une autre source de donn\u00e9es.<\/p>\n<p>\u00a0<\/p>\n<p><\/p>\n<p><\/p>\n<p>L\u2019initiative\u00a0<a href=\"https:\/\/openeo.org\/news\/2018-03-15-poc.html\">openEO<\/a>\u00a0part de ces constatations (besoin d\u2019ex\u00e9cuter des algorithmes l\u00e0 o\u00f9 se trouve la donn\u00e9e\u00a0; les solutions existantes utilisent des API propri\u00e9taires) pour proposer une API neutre en Python. Leur prototype permet d\u00e9j\u00e0 de d\u00e9finir des algorithmes pour GEE en utilisant une API qu\u2019ils veulent transposable \u00e0 d\u2019autres fournisseurs. Toutefois, bien que openEO ait \u00e9t\u00e9 pr\u00e9sent\u00e9 \u00e0 la r\u00e9union OGC \u00e0 Orl\u00e9ans, l\u2019API montr\u00e9e semble leur \u00eatre propre. Il utilise assez peu les mod\u00e8les conceptuels de l\u2019OGC.<\/p>\n<p>\u00a0<\/p>\n<p><\/p>\n<p><\/p>\n<p>Les standards d\u00e9finis par l\u2019OGC s\u2019articulent autour du transfert de donn\u00e9es. Soit en d\u00e9finissant des formats de fichiers (par exemple netCDF) ; soit en d\u00e9finissant des services web permettant de t\u00e9l\u00e9charger ces fichiers. La principale exception est le standard Web Processing Service (WPS) qui permet d\u2019ex\u00e9cuter des algorithmes \u00e0 distance. Cependant, ses possibilit\u00e9s sont limit\u00e9es aux algorithmes pr\u00e9-d\u00e9finis sur le serveur (auquel cas on ne fait que transmettre des param\u00e8tres) ou aux algorithmes exprimables dans un langage proche du SQL (beaucoup plus limit\u00e9 que Python, Java ou autres langages de programmation). Cette situation a amen\u00e9 la NOAA \u00e0 poser trois questions \u00e0 Orl\u00e9ans\u00a0:<\/p>\n<p><\/p>\n<p><\/p>\n<ol class=\"wp-block-list\">\n<li style=\"list-style-type: none;\">\n<ol><\/ol>\n<\/li>\n<\/ol>\n<p>\u00a0<\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\n<li>Quels standards OGC restent pertinents lorsque les donn\u00e9es sont \u00e0 la fois h\u00e9berg\u00e9es et trait\u00e9es par l\u2019informatique en nuage\u00a0?<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p><\/p>\n<p><\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\n<li>Quels standards OGC deviennent non-pertinents lorsque l\u2019utilisateur final (sous forme d\u2019algorithme) est aussi dans le nuage\u00a0?<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p><\/p>\n<p><\/p>\n<ol>\n<li style=\"list-style-type: none;\">\n<ol>\n<li>Quels nouveaux standards OGC ou quelles r\u00e9visions de standards existants sont n\u00e9cessaires\u00a0?<\/li>\n<li>\u00a0<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<p><\/p>\n<p><\/p>\n<p><\/p>\n<p>La r\u00e9ponse \u00e0 la question 2 pourrait \u00eatre \u00ab\u00a0tous les standards web et formats de fichiers\u00a0\u00bb. Ce qui englobe beaucoup des standards les plus populaires de l\u2019OGC\u00a0! Notons toutefois que m\u00eame si ces standards peuvent devenir inutiles pendant la phase d\u2019ex\u00e9cution d\u2019un algorithme par l\u2019informatique en nuage, ils restent pertinents pour r\u00e9cup\u00e9rer le r\u00e9sultat du calcul.<\/p>\n<p>\u00a0<\/p>\n<p><\/p>\n<p><\/p>\n<p>Une r\u00e9ponse \u00e0 la question 3 pourrait \u00eatre\u00a0<a href=\"http:\/\/www.geoapi.org\/\">GeoAPI<\/a>, un standard OGC qui d\u00e9finit des interfaces de programmation depuis plus de 15 ans. GeoAPI poursuit les m\u00eames objectifs que openEO, mais en prenant le probl\u00e8me par le bout oppos\u00e9. OpenEO part du haut (\u00ab\u00a0fournir une image \u00e0 l\u2019utilisateur\u00a0\u00bb), et descend dans les d\u00e9tails au fur et \u00e0 mesure des besoins. Ils peuvent se permettre cette approche car ils d\u00e9finissent leur propre API, qu\u2019ils compl\u00e8tent \u00e0 leur rythme. De l\u2019autre c\u00f4t\u00e9, GeoAPI s\u2019est donn\u00e9 comme mission d\u2019impl\u00e9menter les mod\u00e8les conceptuels standards de l\u2019OGC et de l\u2019ISO. GeoAPI \u00e9vite de cr\u00e9er son propre mod\u00e8le, except\u00e9 pour des besoins d\u2019int\u00e9gration avec le langage de programmation cibl\u00e9. Par exemple, pour repr\u00e9senter une image, GeoAPI s\u2019appuiera sur le mod\u00e8le conceptuel d\u00e9finit par ISO 19123\u00a0<em>(schema for coverage geometry and functions)<\/em>, qui lui-m\u00eame d\u00e9pend de ISO 19107\u00a0<em>(spatial schema)<\/em>, qui d\u00e9pend de ISO 19111\u00a0<em>(spatial referencing by coordinates)<\/em>, qui d\u00e9pend de ISO 19115\u00a0<em>(metadata)<\/em>, qui d\u00e9pend de ISO 19103\u00a0<em>(conceptual schema language)<\/em>\u2026 GeoAPI part donc du bas et monte vers les besoins des utilisateurs en suivant le fil des d\u00e9pendances entre les standards ISO. C\u2019est un processus plus long que l\u2019approche prise par openEO, mais qui tend vers une solution collant mieux aux standards internationaux.<\/p>\n<p>\u00a0<\/p>\n<p><\/p>\n<p><\/p>\n<p>Paradoxalement, l\u2019informatique en nuage remet d\u2019actualit\u00e9 une approche qui \u00e9tait en vogue il y a une vingtaine d\u2019ann\u00e9es, avant d\u2019\u00eatre (temporairement?) \u00e9clips\u00e9e par la vague des protocoles web. Le mode de fonctionnement de Google Earth Engine ressemble au m\u00e9canisme derri\u00e8re les\u00a0<em>Remote Method Invocations<\/em>\u00a0(RMI) du Java, publi\u00e9 en 1997. D\u2019ailleurs, le slogan de Sun Microsystems (le cr\u00e9ateur du langage Java \u00e0 cette \u00e9poque) \u00e9tait\u00a0<em>\u00ab\u00a0The network is the computer\u00a0\u00bb<\/em>. Les API d\u00e9finis par des interfaces Java \u2013 comme GeoAPI \u2013 se pr\u00eatent naturellement \u00e0 une utilisation par l\u2019informatique en nuage. \u00c9tendre cette approche \u00e0 des langages autres que Java \u2013 \u00e0 commencer par Python \u2013 est en cours sur le\u00a0<a href=\"http:\/\/github.com\/opengeospatial\/geoapi\">d\u00e9p\u00f4t de code de GeoAPI<\/a>.<\/p>\n<p><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<section class=\"has_eae_slider elementor-section elementor-top-section elementor-element elementor-element-5a160c29 elementor-section-full_width elementor-section-height-default elementor-section-height-default exad-glass-effect-no wpr-particle-no wpr-jarallax-no wpr-parallax-no wpr-sticky-section-no wpr-equal-height-no exad-sticky-section-no\" data-eae-slider=\"62510\" data-id=\"5a160c29\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-no\">\n\t\t\t\t\t<div class=\"has_eae_slider elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-5424ac08 exad-glass-effect-no exad-sticky-section-no\" data-eae-slider=\"1123\" data-id=\"5424ac08\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-76230477 exad-sticky-section-no exad-glass-effect-no elementor-widget elementor-widget-shortcode\" data-id=\"76230477\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"shortcode.default\">\n\t\t\t\t\t\t\t<div class=\"elementor-shortcode\">\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"5276\" class=\"elementor elementor-5276\" data-elementor-settings=\"{&quot;ha_cmc_init_switcher&quot;:&quot;no&quot;}\">\n\t\t\t\t\t\t<section class=\"has_eae_slider elementor-section elementor-top-section elementor-element elementor-element-267b5fb elementor-section-boxed elementor-section-height-default elementor-section-height-default exad-glass-effect-no wpr-particle-no wpr-jarallax-no wpr-parallax-no wpr-sticky-section-no wpr-equal-height-no exad-sticky-section-no\" data-eae-slider=\"75586\" data-id=\"267b5fb\" data-element_type=\"section\" data-e-type=\"section\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;,&quot;_ha_eqh_enable&quot;:false}\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"has_eae_slider elementor-column elementor-col-50 elementor-top-column elementor-element elementor-element-8dac029 exad-glass-effect-no exad-sticky-section-no\" data-eae-slider=\"54766\" data-id=\"8dac029\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element 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class=\"elementor-screen-only\">Youtube<\/span>\n\t\t\t\t\t\t<i aria-hidden=\"true\" class=\"fab fa-youtube\"><\/i>\t\t\t\t\t<\/a>\n\t\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"<p>Quels standards OGC pour l&rsquo;informatique en nuages ? 17\/04\/2018 Martin Desruisseaux Les membres du consortium Open Geospatial (OGC) se sont r\u00e9unis \u00e0 Orl\u00e9ans du 19 au 23 mars. Depuis peu, ces r\u00e9unions exp\u00e9rimentent une nouvelle formule pour la s\u00e9ance pl\u00e9ni\u00e8re de cl\u00f4ture. Durant la semaine, les membres votent pour un sujet qui sera pr\u00e9sent\u00e9 et d\u00e9battu en s\u00e9ance.\u00a0\u00c0 Orl\u00e9ans, le sujet discut\u00e9 \u00e0 la cl\u00f4ture \u00e9tait latent depuis plusieurs mois. Il avait \u00e9t\u00e9 soulev\u00e9 plus explicitement, sous diff\u00e9rentes formes, \u00e0 au moins deux reprises au cours de la semaine. Depuis une ou deux ann\u00e9es, les agences spatiales \u2013 notamment la NASA et l\u2019ESA \u2013 expriment \u00e0 l\u2019OGC un besoin d\u2019inverser la logique actuelle dans la fa\u00e7on de manipuler les donn\u00e9es. Au lieu d\u2019amener les donn\u00e9es aux algorithmes (c\u2019est-\u00e0-dire de t\u00e9l\u00e9charger des donn\u00e9es \u00e0 partir de serveurs vers le poste du scientifique qui effectuera les calculs), on souhaite amener les algorithmes vers les donn\u00e9es. La raison est que les donn\u00e9es d\u2019observation de la Terre occupent un volume tel que leur t\u00e9l\u00e9chargement peut devenir impraticable. On souhaite plut\u00f4t ex\u00e9cuter les algorithmes l\u00e0 o\u00f9 se trouvent les donn\u00e9es. Ce souhait est d\u00e9j\u00e0 partiellement r\u00e9alis\u00e9 par certains acteurs. Par exemple Google Earth Engine (GEE) permet d\u2019ex\u00e9cuter des algorithmes d\u00e9finis par l\u2019utilisateur sur les serveurs de Google. Le\u00a0guide du d\u00e9veloppeur\u00a0contient un exemple d\u2019algorithme (un calcul d\u2019indice de v\u00e9g\u00e9tation) ex\u00e9cut\u00e9 localement, puis ex\u00e9cut\u00e9 plus efficacement sur les serveurs o\u00f9 se trouvent les donn\u00e9es. Mais cet exemple utilise une interface de programmation (API) propre \u00e0 Google\u00a0; aucun standard g\u00e9ospatial n\u2019y est appliqu\u00e9. Cette conception expose les utilisateurs au risque de verrouillage du fournisseur. Une situation o\u00f9 les algorithmes \u00e9crits pour GEE peuvent \u00eatre difficiles \u00e0 porter vers une autre source de donn\u00e9es. \u00a0 L\u2019initiative\u00a0openEO\u00a0part de ces constatations (besoin d\u2019ex\u00e9cuter des algorithmes l\u00e0 o\u00f9 se trouve la donn\u00e9e\u00a0; les solutions existantes utilisent des API propri\u00e9taires) pour proposer une API neutre en Python. Leur prototype permet d\u00e9j\u00e0 de d\u00e9finir des algorithmes pour GEE en utilisant une API qu\u2019ils veulent transposable \u00e0 d\u2019autres fournisseurs. Toutefois, bien que openEO ait \u00e9t\u00e9 pr\u00e9sent\u00e9 \u00e0 la r\u00e9union OGC \u00e0 Orl\u00e9ans, l\u2019API montr\u00e9e semble leur \u00eatre propre. Il utilise assez peu les mod\u00e8les conceptuels de l\u2019OGC. \u00a0 Les standards d\u00e9finis par l\u2019OGC s\u2019articulent autour du transfert de donn\u00e9es. Soit en d\u00e9finissant des formats de fichiers (par exemple netCDF) ; soit en d\u00e9finissant des services web permettant de t\u00e9l\u00e9charger ces fichiers. La principale exception est le standard Web Processing Service (WPS) qui permet d\u2019ex\u00e9cuter des algorithmes \u00e0 distance. Cependant, ses possibilit\u00e9s sont limit\u00e9es aux algorithmes pr\u00e9-d\u00e9finis sur le serveur (auquel cas on ne fait que transmettre des param\u00e8tres) ou aux algorithmes exprimables dans un langage proche du SQL (beaucoup plus limit\u00e9 que Python, Java ou autres langages de programmation). Cette situation a amen\u00e9 la NOAA \u00e0 poser trois questions \u00e0 Orl\u00e9ans\u00a0: La r\u00e9ponse \u00e0 la question 2 pourrait \u00eatre \u00ab\u00a0tous les standards web et formats de fichiers\u00a0\u00bb. Ce qui englobe beaucoup des standards les plus populaires de l\u2019OGC\u00a0! Notons toutefois que m\u00eame si ces standards peuvent devenir inutiles pendant la phase d\u2019ex\u00e9cution d\u2019un algorithme par l\u2019informatique en nuage, ils restent pertinents pour r\u00e9cup\u00e9rer le r\u00e9sultat du calcul. \u00a0 Une r\u00e9ponse \u00e0 la question 3 pourrait \u00eatre\u00a0GeoAPI, un standard OGC qui d\u00e9finit des interfaces de programmation depuis plus de 15 ans. GeoAPI poursuit les m\u00eames objectifs que openEO, mais en prenant le probl\u00e8me par le bout oppos\u00e9. OpenEO part du haut (\u00ab\u00a0fournir une image \u00e0 l\u2019utilisateur\u00a0\u00bb), et descend dans les d\u00e9tails au fur et \u00e0 mesure des besoins. Ils peuvent se permettre cette approche car ils d\u00e9finissent leur propre API, qu\u2019ils compl\u00e8tent \u00e0 leur rythme. De l\u2019autre c\u00f4t\u00e9, GeoAPI s\u2019est donn\u00e9 comme mission d\u2019impl\u00e9menter les mod\u00e8les conceptuels standards de l\u2019OGC et de l\u2019ISO. GeoAPI \u00e9vite de cr\u00e9er son propre mod\u00e8le, except\u00e9 pour des besoins d\u2019int\u00e9gration avec le langage de programmation cibl\u00e9. Par exemple, pour repr\u00e9senter une image, GeoAPI s\u2019appuiera sur le mod\u00e8le conceptuel d\u00e9finit par ISO 19123\u00a0(schema for coverage geometry and functions), qui lui-m\u00eame d\u00e9pend de ISO 19107\u00a0(spatial schema), qui d\u00e9pend de ISO 19111\u00a0(spatial referencing by coordinates), qui d\u00e9pend de ISO 19115\u00a0(metadata), qui d\u00e9pend de ISO 19103\u00a0(conceptual schema language)\u2026 GeoAPI part donc du bas et monte vers les besoins des utilisateurs en suivant le fil des d\u00e9pendances entre les standards ISO. C\u2019est un processus plus long que l\u2019approche prise par openEO, mais qui tend vers une solution collant mieux aux standards internationaux. \u00a0 Paradoxalement, l\u2019informatique en nuage remet d\u2019actualit\u00e9 une approche qui \u00e9tait en vogue il y a une vingtaine d\u2019ann\u00e9es, avant d\u2019\u00eatre (temporairement?) \u00e9clips\u00e9e par la vague des protocoles web. Le mode de fonctionnement de Google Earth Engine ressemble au m\u00e9canisme derri\u00e8re les\u00a0Remote Method Invocations\u00a0(RMI) du Java, publi\u00e9 en 1997. D\u2019ailleurs, le slogan de Sun Microsystems (le cr\u00e9ateur du langage Java \u00e0 cette \u00e9poque) \u00e9tait\u00a0\u00ab\u00a0The network is the computer\u00a0\u00bb. Les API d\u00e9finis par des interfaces Java \u2013 comme GeoAPI \u2013 se pr\u00eatent naturellement \u00e0 une utilisation par l\u2019informatique en nuage. \u00c9tendre cette approche \u00e0 des langages autres que Java \u2013 \u00e0 commencer par Python \u2013 est en cours sur le\u00a0d\u00e9p\u00f4t de code de GeoAPI.<\/p>","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_umich_oidc_access":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-5120","post","type-post","status-publish","format-standard","hentry","category-actus"],"aioseo_notices":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/posts\/5120","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/comments?post=5120"}],"version-history":[{"count":9,"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/posts\/5120\/revisions"}],"predecessor-version":[{"id":9473,"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/posts\/5120\/revisions\/9473"}],"wp:attachment":[{"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/media?parent=5120"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/categories?post=5120"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.geomatys.com\/en\/wp-json\/wp\/v2\/tags?post=5120"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}