Merge pull request #2371 from rouault/epsg10_part2

EPSG v10 update part 2: ingest DatumEnsemble from the database

13 files changed, 481 insertions, 98 deletions

diff --git a/docs/source/apps/projinfo.rst b/docs/source/apps/projinfo.rst
index 05184ef9..a07cf709 100644
--- a/docs/source/apps/projinfo.rst
+++ b/docs/source/apps/projinfo.rst
@@ -16,7 +16,7 @@ Synopsis
 ********
 
     | **projinfo**
-    |    [-o formats] [-k crs|operation|datum|ellipsoid] [--summary] [-q]
+    |    [-o formats] [-k crs|operation|datum|ensemble|ellipsoid] [--summary] [-q]
     |    [[--area name_or_code] | [--bbox west_long,south_lat,east_long,north_lat]]
     |    [--spatial-test contains|intersects]
     |    [--crs-extent-use none|both|intersection|smallest]
@@ -86,7 +86,7 @@ The following control parameters can appear in any order:
     .. note:: Before PROJ 6.3.0, WKT1:GDAL was implicitly calling --boundcrs-to-wgs84.
               This is no longer the case.
 
-.. option:: -k crs|operation|datum|ellipsoid
+.. option:: -k crs|operation|datum|ensemble|ellipsoid
 
     When used to query a single object with a AUTHORITY:CODE, determines the (k)ind of the object
     in case there are CRS, coordinate operations or ellipsoids with the same CODE.
diff --git a/include/proj/io.hpp b/include/proj/io.hpp
index 20dcedfe..de8a90fc 100644
--- a/include/proj/io.hpp
+++ b/include/proj/io.hpp
@@ -1032,6 +1032,8 @@ class PROJ_GCC_DLL AuthorityFactory {
         DYNAMIC_GEODETIC_REFERENCE_FRAME,
         /** Object of type datum::DynamicVerticalReferenceFrame */
         DYNAMIC_VERTICAL_REFERENCE_FRAME,
+        /** Object of type datum::DatumEnsemble */
+        DATUM_ENSEMBLE,
     };
 
     PROJ_DLL std::set<std::string>
@@ -1225,6 +1227,18 @@ class PROJ_GCC_DLL AuthorityFactory {
 
   private:
     PROJ_OPAQUE_PRIVATE_DATA
+
+    PROJ_INTERNAL void
+    createGeodeticDatumOrEnsemble(const std::string &code,
+                                  datum::GeodeticReferenceFramePtr &outDatum,
+                                  datum::DatumEnsemblePtr &outDatumEnsemble,
+                                  bool turnEnsembleAsDatum) const;
+
+    PROJ_INTERNAL void
+    createVerticalDatumOrEnsemble(const std::string &code,
+                                  datum::VerticalReferenceFramePtr &outDatum,
+                                  datum::DatumEnsemblePtr &outDatumEnsemble,
+                                  bool turnEnsembleAsDatum) const;
 };
 
 // ---------------------------------------------------------------------------
diff --git a/src/apps/projinfo.cpp b/src/apps/projinfo.cpp
index 37b76346..6ee5925a 100644
--- a/src/apps/projinfo.cpp
+++ b/src/apps/projinfo.cpp
@@ -79,7 +79,8 @@ struct OutputOptions {
 
 static void usage() {
     std::cerr
-        << "usage: projinfo [-o formats] [-k crs|operation|datum|ellipsoid] "
+        << "usage: projinfo [-o formats] "
+           "[-k crs|operation|datum|ensemble|ellipsoid] "
            "[--summary] [-q]"
         << std::endl
         << "                ([--area name_or_code] | "
@@ -184,11 +185,11 @@ static BaseObjectNNPtr buildObject(
             auto urn = "urn:ogc:def:coordinateOperation:" + tokens[0] + "::" +
                        tokens[1];
             obj = createFromUserInput(urn, dbContext).as_nullable();
-        } else if (kind == "ellipsoid" && tokens.size() == 2) {
-            auto urn = "urn:ogc:def:ellipsoid:" + tokens[0] + "::" + tokens[1];
-            obj = createFromUserInput(urn, dbContext).as_nullable();
-        } else if (kind == "datum" && tokens.size() == 2) {
-            auto urn = "urn:ogc:def:datum:" + tokens[0] + "::" + tokens[1];
+        } else if ((kind == "ellipsoid" || kind == "datum" ||
+                    kind == "ensemble") &&
+                   tokens.size() == 2) {
+            auto urn =
+                "urn:ogc:def:" + kind + ":" + tokens[0] + "::" + tokens[1];
             obj = createFromUserInput(urn, dbContext).as_nullable();
         } else {
             // Convenience to be able to use C escaped strings...
@@ -222,6 +223,9 @@ static BaseObjectNNPtr buildObject(
                         AuthorityFactory::ObjectType::ELLIPSOID);
                 else if (kind == "datum")
                     allowedTypes.push_back(AuthorityFactory::ObjectType::DATUM);
+                else if (kind == "ensemble")
+                    allowedTypes.push_back(
+                        AuthorityFactory::ObjectType::DATUM_ENSEMBLE);
                 constexpr size_t limitResultCount = 10;
                 auto factory = AuthorityFactory::create(NN_NO_CHECK(dbContext),
                                                         std::string());
@@ -929,6 +933,8 @@ int main(int argc, char **argv) {
                 objectKind = "ellipsoid";
             } else if (ci_equal(kind, "datum")) {
                 objectKind = "datum";
+            } else if (ci_equal(kind, "ensemble")) {
+                objectKind = "ensemble";
             } else {
                 std::cerr << "Unrecognized value for option -k: " << kind
                           << std::endl;
diff --git a/src/iso19111/c_api.cpp b/src/iso19111/c_api.cpp
index 90a414c6..cbbdcaa8 100644
--- a/src/iso19111/c_api.cpp
+++ b/src/iso19111/c_api.cpp
@@ -675,6 +675,9 @@ PJ *proj_create_from_database(PJ_CONTEXT *ctx, const char *auth_name,
                           codeStr, usePROJAlternativeGridNames != 0)
                       .as_nullable();
             break;
+        case PJ_CATEGORY_DATUM_ENSEMBLE:
+            obj = factory->createDatumEnsemble(codeStr).as_nullable();
+            break;
         }
         return pj_obj_create(ctx, NN_NO_CHECK(obj));
     } catch (const std::exception &e) {
@@ -916,7 +919,7 @@ convertPJObjectTypeToObjectType(PJ_TYPE type, bool &valid) {
         break;
 
     case PJ_TYPE_DATUM_ENSEMBLE:
-        cppType = AuthorityFactory::ObjectType::DATUM;
+        cppType = AuthorityFactory::ObjectType::DATUM_ENSEMBLE;
         break;
 
     case PJ_TYPE_TEMPORAL_DATUM:
diff --git a/src/iso19111/datum.cpp b/src/iso19111/datum.cpp
index 5bc8074c..e29f6319 100644
--- a/src/iso19111/datum.cpp
+++ b/src/iso19111/datum.cpp
@@ -1731,6 +1731,14 @@ void DatumEnsemble::_exportToWKT(
     formatter->startNode(io::WKTConstants::ENSEMBLEACCURACY, false);
     formatter->add(positionalAccuracy()->value());
     formatter->endNode();
+
+    // In theory, we should do the following, but currently the WKT grammar
+    // doesn't allow this
+    // ObjectUsage::baseExportToWKT(formatter);
+    if (formatter->outputId()) {
+        formatID(formatter);
+    }
+
     formatter->endNode();
 }
 //! @endcond
diff --git a/src/iso19111/factory.cpp b/src/iso19111/factory.cpp
index 5d02aeea..0ccfefc1 100644
--- a/src/iso19111/factory.cpp
+++ b/src/iso19111/factory.cpp
@@ -192,6 +192,13 @@ struct DatabaseContext::Private {
     void cache(const std::string &code,
                const datum::GeodeticReferenceFrameNNPtr &datum);
 
+    datum::DatumEnsemblePtr
+        // cppcheck-suppress functionStatic
+        getDatumEnsembleFromCache(const std::string &code);
+    // cppcheck-suppress functionStatic
+    void cache(const std::string &code,
+               const datum::DatumEnsembleNNPtr &datumEnsemble);
+
     datum::EllipsoidPtr
         // cppcheck-suppress functionStatic
         getEllipsoidFromCache(const std::string &code);
@@ -258,6 +265,7 @@ struct DatabaseContext::Private {
     LRUCacheOfObjects cacheCRS_{CACHE_SIZE};
     LRUCacheOfObjects cacheEllipsoid_{CACHE_SIZE};
     LRUCacheOfObjects cacheGeodeticDatum_{CACHE_SIZE};
+    LRUCacheOfObjects cacheDatumEnsemble_{CACHE_SIZE};
     LRUCacheOfObjects cachePrimeMeridian_{CACHE_SIZE};
     LRUCacheOfObjects cacheCS_{CACHE_SIZE};
     LRUCacheOfObjects cacheExtent_{CACHE_SIZE};
@@ -417,6 +425,22 @@ void DatabaseContext::Private::cache(
 
 // ---------------------------------------------------------------------------
 
+datum::DatumEnsemblePtr
+DatabaseContext::Private::getDatumEnsembleFromCache(const std::string &code) {
+    util::BaseObjectPtr obj;
+    getFromCache(cacheDatumEnsemble_, code, obj);
+    return std::static_pointer_cast<datum::DatumEnsemble>(obj);
+}
+
+// ---------------------------------------------------------------------------
+
+void DatabaseContext::Private::cache(
+    const std::string &code, const datum::DatumEnsembleNNPtr &datumEnsemble) {
+    insertIntoCache(cacheDatumEnsemble_, code, datumEnsemble.as_nullable());
+}
+
+// ---------------------------------------------------------------------------
+
 datum::EllipsoidPtr
 DatabaseContext::Private::getEllipsoidFromCache(const std::string &code) {
     util::BaseObjectPtr obj;
@@ -1064,18 +1088,6 @@ std::string DatabaseContext::getOldProjGridName(const std::string &gridName) {
 
 // ---------------------------------------------------------------------------
 
-// FIXME: as we don't support datum ensemble yet, add it from name
-static std::string removeEnsembleSuffix(const std::string &name) {
-    if (name == "World Geodetic System 1984 ensemble") {
-        return "World Geodetic System 1984";
-    } else if (name == "European Terrestrial Reference System 1989 ensemble") {
-        return "European Terrestrial Reference System 1989";
-    }
-    return name;
-}
-
-// ---------------------------------------------------------------------------
-
 /** \brief Gets the alias name from an official name.
  *
  * @param officialName Official name. Mandatory
@@ -2012,18 +2024,38 @@ AuthorityFactory::createEllipsoid(const std::string &code) const {
 
 datum::GeodeticReferenceFrameNNPtr
 AuthorityFactory::createGeodeticDatum(const std::string &code) const {
+
+    datum::GeodeticReferenceFramePtr datum;
+    datum::DatumEnsemblePtr datumEnsemble;
+    constexpr bool turnEnsembleAsDatum = true;
+    createGeodeticDatumOrEnsemble(code, datum, datumEnsemble,
+                                  turnEnsembleAsDatum);
+    return NN_NO_CHECK(datum);
+}
+
+// ---------------------------------------------------------------------------
+
+void AuthorityFactory::createGeodeticDatumOrEnsemble(
+    const std::string &code, datum::GeodeticReferenceFramePtr &outDatum,
+    datum::DatumEnsemblePtr &outDatumEnsemble, bool turnEnsembleAsDatum) const {
     const auto cacheKey(d->authority() + code);
     {
-        auto datum = d->context()->d->getGeodeticDatumFromCache(cacheKey);
-        if (datum) {
-            return NN_NO_CHECK(datum);
+        outDatumEnsemble = d->context()->d->getDatumEnsembleFromCache(cacheKey);
+        if (outDatumEnsemble) {
+            if (!turnEnsembleAsDatum)
+                return;
+            outDatumEnsemble = nullptr;
+        }
+        outDatum = d->context()->d->getGeodeticDatumFromCache(cacheKey);
+        if (outDatum) {
+            return;
         }
     }
     auto res =
         d->runWithCodeParam("SELECT name, ellipsoid_auth_name, ellipsoid_code, "
                             "prime_meridian_auth_name, prime_meridian_code, "
                             "publication_date, frame_reference_epoch, "
-                            "deprecated FROM geodetic_datum "
+                            "ensemble_accuracy, deprecated FROM geodetic_datum "
                             "WHERE "
                             "auth_name = ? AND code = ?",
                             code);
@@ -2040,29 +2072,63 @@ AuthorityFactory::createGeodeticDatum(const std::string &code) const {
         const auto &prime_meridian_code = row[4];
         const auto &publication_date = row[5];
         const auto &frame_reference_epoch = row[6];
-        const bool deprecated = row[7] == "1";
-        auto ellipsoid = d->createFactory(ellipsoid_auth_name)
-                             ->createEllipsoid(ellipsoid_code);
-        auto pm = d->createFactory(prime_meridian_auth_name)
-                      ->createPrimeMeridian(prime_meridian_code);
-        auto props = d->createPropertiesSearchUsages(
-            "geodetic_datum", code, removeEnsembleSuffix(name), deprecated);
-        auto anchor = util::optional<std::string>();
-        if (!publication_date.empty()) {
-            props.set("PUBLICATION_DATE", publication_date);
-        }
-        auto datum =
-            frame_reference_epoch.empty()
-                ? datum::GeodeticReferenceFrame::create(props, ellipsoid,
-                                                        anchor, pm)
-                : util::nn_static_pointer_cast<datum::GeodeticReferenceFrame>(
-                      datum::DynamicGeodeticReferenceFrame::create(
-                          props, ellipsoid, anchor, pm,
-                          common::Measure(c_locale_stod(frame_reference_epoch),
-                                          common::UnitOfMeasure::YEAR),
-                          util::optional<std::string>()));
-        d->context()->d->cache(cacheKey, datum);
-        return datum;
+        const auto &ensemble_accuracy = row[7];
+        const bool deprecated = row[8] == "1";
+
+        std::string massagedName = name;
+        if (turnEnsembleAsDatum) {
+            if (name == "World Geodetic System 1984 ensemble") {
+                massagedName = "World Geodetic System 1984";
+            } else if (name ==
+                       "European Terrestrial Reference System 1989 ensemble") {
+                massagedName = "European Terrestrial Reference System 1989";
+            }
+        }
+        auto props = d->createPropertiesSearchUsages("geodetic_datum", code,
+                                                     massagedName, deprecated);
+
+        if (!turnEnsembleAsDatum && !ensemble_accuracy.empty()) {
+            auto resMembers =
+                d->run("SELECT member_auth_name, member_code FROM "
+                       "geodetic_datum_ensemble_member WHERE "
+                       "ensemble_auth_name = ? AND ensemble_code = ? "
+                       "ORDER BY sequence",
+                       {d->authority(), code});
+
+            std::vector<datum::DatumNNPtr> members;
+            for (const auto &memberRow : resMembers) {
+                members.push_back(
+                    d->createFactory(memberRow[0])->createDatum(memberRow[1]));
+            }
+            auto datumEnsemble = datum::DatumEnsemble::create(
+                props, std::move(members),
+                metadata::PositionalAccuracy::create(ensemble_accuracy));
+            d->context()->d->cache(cacheKey, datumEnsemble);
+            outDatumEnsemble = datumEnsemble.as_nullable();
+        } else {
+            auto ellipsoid = d->createFactory(ellipsoid_auth_name)
+                                 ->createEllipsoid(ellipsoid_code);
+            auto pm = d->createFactory(prime_meridian_auth_name)
+                          ->createPrimeMeridian(prime_meridian_code);
+
+            auto anchor = util::optional<std::string>();
+            if (!publication_date.empty()) {
+                props.set("PUBLICATION_DATE", publication_date);
+            }
+            auto datum = frame_reference_epoch.empty()
+                             ? datum::GeodeticReferenceFrame::create(
+                                   props, ellipsoid, anchor, pm)
+                             : util::nn_static_pointer_cast<
+                                   datum::GeodeticReferenceFrame>(
+                                   datum::DynamicGeodeticReferenceFrame::create(
+                                       props, ellipsoid, anchor, pm,
+                                       common::Measure(
+                                           c_locale_stod(frame_reference_epoch),
+                                           common::UnitOfMeasure::YEAR),
+                                       util::optional<std::string>()));
+            d->context()->d->cache(cacheKey, datum);
+            outDatum = datum.as_nullable();
+        }
     } catch (const std::exception &ex) {
         throw buildFactoryException("geodetic reference frame", code, ex);
     }
@@ -2080,9 +2146,23 @@ AuthorityFactory::createGeodeticDatum(const std::string &code) const {
 
 datum::VerticalReferenceFrameNNPtr
 AuthorityFactory::createVerticalDatum(const std::string &code) const {
+    datum::VerticalReferenceFramePtr datum;
+    datum::DatumEnsemblePtr datumEnsemble;
+    constexpr bool turnEnsembleAsDatum = true;
+    createVerticalDatumOrEnsemble(code, datum, datumEnsemble,
+                                  turnEnsembleAsDatum);
+    return NN_NO_CHECK(datum);
+}
+
+// ---------------------------------------------------------------------------
+
+void AuthorityFactory::createVerticalDatumOrEnsemble(
+    const std::string &code, datum::VerticalReferenceFramePtr &outDatum,
+    datum::DatumEnsemblePtr &outDatumEnsemble, bool turnEnsembleAsDatum) const {
     auto res =
         d->runWithCodeParam("SELECT name, publication_date, "
-                            "frame_reference_epoch, deprecated FROM "
+                            "frame_reference_epoch, ensemble_accuracy, "
+                            "deprecated FROM "
                             "vertical_datum WHERE auth_name = ? AND code = ?",
                             code);
     if (res.empty()) {
@@ -2094,24 +2174,49 @@ AuthorityFactory::createVerticalDatum(const std::string &code) const {
         const auto &name = row[0];
         const auto &publication_date = row[1];
         const auto &frame_reference_epoch = row[2];
-        const bool deprecated = row[3] == "1";
+        const auto &ensemble_accuracy = row[3];
+        const bool deprecated = row[4] == "1";
         auto props = d->createPropertiesSearchUsages("vertical_datum", code,
                                                      name, deprecated);
-        if (!publication_date.empty()) {
-            props.set("PUBLICATION_DATE", publication_date);
-        }
-        if (d->authority() == "ESRI" && starts_with(code, "from_geogdatum_")) {
-            props.set("VERT_DATUM_TYPE", "2002");
-        }
-        auto anchor = util::optional<std::string>();
-        if (frame_reference_epoch.empty()) {
-            return datum::VerticalReferenceFrame::create(props, anchor);
+        if (!turnEnsembleAsDatum && !ensemble_accuracy.empty()) {
+            auto resMembers =
+                d->run("SELECT member_auth_name, member_code FROM "
+                       "vertical_datum_ensemble_member WHERE "
+                       "ensemble_auth_name = ? AND ensemble_code = ? "
+                       "ORDER BY sequence",
+                       {d->authority(), code});
+
+            std::vector<datum::DatumNNPtr> members;
+            for (const auto &memberRow : resMembers) {
+                members.push_back(
+                    d->createFactory(memberRow[0])->createDatum(memberRow[1]));
+            }
+            auto datumEnsemble = datum::DatumEnsemble::create(
+                props, std::move(members),
+                metadata::PositionalAccuracy::create(ensemble_accuracy));
+            outDatumEnsemble = datumEnsemble.as_nullable();
         } else {
-            return datum::DynamicVerticalReferenceFrame::create(
-                props, anchor, util::optional<datum::RealizationMethod>(),
-                common::Measure(c_locale_stod(frame_reference_epoch),
-                                common::UnitOfMeasure::YEAR),
-                util::optional<std::string>());
+            if (!publication_date.empty()) {
+                props.set("PUBLICATION_DATE", publication_date);
+            }
+            if (d->authority() == "ESRI" &&
+                starts_with(code, "from_geogdatum_")) {
+                props.set("VERT_DATUM_TYPE", "2002");
+            }
+            auto anchor = util::optional<std::string>();
+            if (frame_reference_epoch.empty()) {
+                outDatum = datum::VerticalReferenceFrame::create(props, anchor)
+                               .as_nullable();
+            } else {
+                outDatum =
+                    datum::DynamicVerticalReferenceFrame::create(
+                        props, anchor,
+                        util::optional<datum::RealizationMethod>(),
+                        common::Measure(c_locale_stod(frame_reference_epoch),
+                                        common::UnitOfMeasure::YEAR),
+                        util::optional<std::string>())
+                        .as_nullable();
+            }
         }
     } catch (const std::exception &ex) {
         throw buildFactoryException("vertical reference frame", code, ex);
@@ -2472,20 +2577,24 @@ AuthorityFactory::createGeodeticCRS(const std::string &code,
 
         auto cs =
             d->createFactory(cs_auth_name)->createCoordinateSystem(cs_code);
-        auto datum =
-            d->createFactory(datum_auth_name)->createGeodeticDatum(datum_code);
+        datum::GeodeticReferenceFramePtr datum;
+        datum::DatumEnsemblePtr datumEnsemble;
+        constexpr bool turnEnsembleAsDatum = false;
+        d->createFactory(datum_auth_name)
+            ->createGeodeticDatumOrEnsemble(datum_code, datum, datumEnsemble,
+                                            turnEnsembleAsDatum);
 
         auto ellipsoidalCS =
             util::nn_dynamic_pointer_cast<cs::EllipsoidalCS>(cs);
         if ((type == GEOG_2D || type == GEOG_3D) && ellipsoidalCS) {
             auto crsRet = crs::GeographicCRS::create(
-                props, datum, NN_NO_CHECK(ellipsoidalCS));
+                props, datum, datumEnsemble, NN_NO_CHECK(ellipsoidalCS));
             d->context()->d->cache(cacheKey, crsRet);
             return crsRet;
         }
         auto geocentricCS = util::nn_dynamic_pointer_cast<cs::CartesianCS>(cs);
         if (type == GEOCENTRIC && geocentricCS) {
-            auto crsRet = crs::GeodeticCRS::create(props, datum,
+            auto crsRet = crs::GeodeticCRS::create(props, datum, datumEnsemble,
                                                    NN_NO_CHECK(geocentricCS));
             d->context()->d->cache(cacheKey, crsRet);
             return crsRet;
@@ -2539,16 +2648,19 @@ AuthorityFactory::createVerticalCRS(const std::string &code) const {
         const bool deprecated = row[5] == "1";
         auto cs =
             d->createFactory(cs_auth_name)->createCoordinateSystem(cs_code);
-        auto datum =
-            d->createFactory(datum_auth_name)->createVerticalDatum(datum_code);
-
+        datum::VerticalReferenceFramePtr datum;
+        datum::DatumEnsemblePtr datumEnsemble;
+        constexpr bool turnEnsembleAsDatum = false;
+        d->createFactory(datum_auth_name)
+            ->createVerticalDatumOrEnsemble(datum_code, datum, datumEnsemble,
+                                            turnEnsembleAsDatum);
         auto props = d->createPropertiesSearchUsages("vertical_crs", code, name,
                                                      deprecated);
 
         auto verticalCS = util::nn_dynamic_pointer_cast<cs::VerticalCS>(cs);
         if (verticalCS) {
-            auto crsRet =
-                crs::VerticalCRS::create(props, datum, NN_NO_CHECK(verticalCS));
+            auto crsRet = crs::VerticalCRS::create(props, datum, datumEnsemble,
+                                                   NN_NO_CHECK(verticalCS));
             d->context()->d->cache(cacheKey, crsRet);
             return crsRet;
         }
@@ -5340,6 +5452,11 @@ AuthorityFactory::getAuthorityCodes(const ObjectType &type,
     case ObjectType::CONCATENATED_OPERATION:
         sql = "SELECT code FROM concatenated_operation WHERE ";
         break;
+    case ObjectType::DATUM_ENSEMBLE:
+        sql = "SELECT code FROM object_view WHERE table_name IN "
+              "('geodetic_datum', 'vertical_datum') AND "
+              "type = 'ensemble' AND ";
+        break;
     }
 
     sql += "auth_name = ?";
@@ -5617,7 +5734,7 @@ std::string AuthorityFactory::getOfficialNameFromAlias(
                 if (res.empty()) { // shouldn't happen normally
                     return std::string();
                 }
-                return removeEnsembleSuffix(res.front()[0]);
+                return res.front()[0];
             }
         }
         return std::string();
@@ -5667,7 +5784,7 @@ std::string AuthorityFactory::getOfficialNameFromAlias(
         outTableName = row[1];
         outAuthName = row[2];
         outCode = row[3];
-        return removeEnsembleSuffix(row[0]);
+        return row[0];
     }
 }
 
@@ -5849,12 +5966,28 @@ AuthorityFactory::createObjectsFromNameEx(
                     res.emplace_back(
                         TableType("concatenated_operation", std::string()));
                     break;
+                case ObjectType::DATUM_ENSEMBLE:
+                    res.emplace_back(TableType("geodetic_datum", "ensemble"));
+                    res.emplace_back(TableType("vertical_datum", "ensemble"));
+                    break;
                 }
             }
         }
         return res;
     };
 
+    bool datumEnsembleAllowed = false;
+    if (allowedObjectTypes.empty()) {
+        datumEnsembleAllowed = true;
+    } else {
+        for (const auto type : allowedObjectTypes) {
+            if (type == ObjectType::DATUM_ENSEMBLE) {
+                datumEnsembleAllowed = true;
+                break;
+            }
+        }
+    }
+
     const auto listTableNameType = getTableAndTypeConstraints();
     bool first = true;
     ListOfParams params;
@@ -5872,6 +6005,8 @@ AuthorityFactory::createObjectsFromNameEx(
         if (!tableNameTypePair.second.empty()) {
             if (tableNameTypePair.second == "frame_reference_epoch") {
                 sql += "AND frame_reference_epoch IS NOT NULL ";
+            } else if (tableNameTypePair.second == "ensemble") {
+                sql += "AND ensemble_accuracy IS NOT NULL ";
             } else {
                 sql += "AND type = '";
                 sql += tableNameTypePair.second;
@@ -5906,6 +6041,8 @@ AuthorityFactory::createObjectsFromNameEx(
         if (!tableNameTypePair.second.empty()) {
             if (tableNameTypePair.second == "frame_reference_epoch") {
                 sql += "AND ov.frame_reference_epoch IS NOT NULL ";
+            } else if (tableNameTypePair.second == "ensemble") {
+                sql += "AND ov.ensemble_accuracy IS NOT NULL ";
             } else {
                 sql += "AND ov.type = '";
                 sql += tableNameTypePair.second;
@@ -6053,7 +6190,7 @@ AuthorityFactory::createObjectsFromNameEx(
                 break;
             }
             auto factory = d->createFactory(auth_name);
-            auto getObject = [&factory](
+            auto getObject = [&factory, datumEnsembleAllowed](
                 const std::string &l_table_name,
                 const std::string &l_code) -> common::IdentifiedObjectNNPtr {
                 if (l_table_name == "prime_meridian") {
@@ -6061,8 +6198,32 @@ AuthorityFactory::createObjectsFromNameEx(
                 } else if (l_table_name == "ellipsoid") {
                     return factory->createEllipsoid(l_code);
                 } else if (l_table_name == "geodetic_datum") {
+                    if (datumEnsembleAllowed) {
+                        datum::GeodeticReferenceFramePtr datum;
+                        datum::DatumEnsemblePtr datumEnsemble;
+                        constexpr bool turnEnsembleAsDatum = false;
+                        factory->createGeodeticDatumOrEnsemble(
+                            l_code, datum, datumEnsemble, turnEnsembleAsDatum);
+                        if (datum) {
+                            return NN_NO_CHECK(datum);
+                        }
+                        assert(datumEnsemble);
+                        return NN_NO_CHECK(datumEnsemble);
+                    }
                     return factory->createGeodeticDatum(l_code);
                 } else if (l_table_name == "vertical_datum") {
+                    if (datumEnsembleAllowed) {
+                        datum::VerticalReferenceFramePtr datum;
+                        datum::DatumEnsemblePtr datumEnsemble;
+                        constexpr bool turnEnsembleAsDatum = false;
+                        factory->createVerticalDatumOrEnsemble(
+                            l_code, datum, datumEnsemble, turnEnsembleAsDatum);
+                        if (datum) {
+                            return NN_NO_CHECK(datum);
+                        }
+                        assert(datumEnsemble);
+                        return NN_NO_CHECK(datumEnsemble);
+                    }
                     return factory->createVerticalDatum(l_code);
                 } else if (l_table_name == "geodetic_crs") {
                     return factory->createGeodeticCRS(l_code);
diff --git a/src/iso19111/io.cpp b/src/iso19111/io.cpp
index f4ec7740..b2e5822b 100644
--- a/src/iso19111/io.cpp
+++ b/src/iso19111/io.cpp
@@ -2110,6 +2110,10 @@ GeodeticReferenceFrameNNPtr WKTParser::Private::buildGeodeticReferenceFrame(
             name = "World Geodetic System 1984";
             authNameFromAlias = Identifier::EPSG;
             codeFromAlias = "6326";
+        } else if (name == "D_ETRS_1989") {
+            name = "European Terrestrial Reference System 1989";
+            authNameFromAlias = Identifier::EPSG;
+            codeFromAlias = "6258";
         } else {
             tableNameForAlias = "geodetic_datum";
         }
@@ -6263,6 +6267,9 @@ static BaseObjectNNPtr createFromUserInput(const std::string &text,
         if (type == "datum") {
             return factory->createDatum(code);
         }
+        if (type == "ensemble") {
+            return factory->createDatumEnsemble(code);
+        }
         if (type == "ellipsoid") {
             return factory->createEllipsoid(code);
         }
@@ -6381,6 +6388,8 @@ static BaseObjectNNPtr createFromUserInput(const std::string &text,
                                               AuthorityFactory::ObjectType::
                                                   DATUM,
                                               AuthorityFactory::ObjectType::
+                                                  DATUM_ENSEMBLE,
+                                              AuthorityFactory::ObjectType::
                                                   COORDINATE_OPERATION},
                     goOn);
             } catch (const std::exception &) {
diff --git a/src/proj.h b/src/proj.h
index e77a5984..4185ddbf 100644
--- a/src/proj.h
+++ b/src/proj.h
@@ -694,7 +694,8 @@ typedef enum
     PJ_CATEGORY_PRIME_MERIDIAN,
     PJ_CATEGORY_DATUM,
     PJ_CATEGORY_CRS,
-    PJ_CATEGORY_COORDINATE_OPERATION
+    PJ_CATEGORY_COORDINATE_OPERATION,
+    PJ_CATEGORY_DATUM_ENSEMBLE
 } PJ_CATEGORY;
 
 /** \brief Object type. */
diff --git a/test/cli/testprojinfo b/test/cli/testprojinfo
index 62713af5..c31cfef0 100755
--- a/test/cli/testprojinfo
+++ b/test/cli/testprojinfo
@@ -171,6 +171,10 @@ echo 'Testing -k datum EPSG:6326' >> ${OUT}
 $EXE -k datum EPSG:6326 >>${OUT} 2>&1
 echo "" >>${OUT}
 
+echo 'Testing -k ensemble WGS84' >> ${OUT}
+$EXE -k ensemble WGS84 >>${OUT} 2>&1
+echo "" >>${OUT}
+
 echo 'Testing -k operation EPSG:8457 -o PROJ -q' >> ${OUT}
 $EXE -k operation EPSG:8457 -o PROJ -q >>${OUT} 2>&1
 echo "" >>${OUT}
diff --git a/test/cli/testprojinfo_out.dist b/test/cli/testprojinfo_out.dist
index 7da5add7..174f11d3 100644
--- a/test/cli/testprojinfo_out.dist
+++ b/test/cli/testprojinfo_out.dist
@@ -4,9 +4,16 @@ PROJ.4 string:
 
 WKT2:2019 string:
 GEOGCRS["WGS 84",
-    DATUM["World Geodetic System 1984",
+    ENSEMBLE["World Geodetic System 1984 ensemble",
+        MEMBER["World Geodetic System 1984 (Transit)"],
+        MEMBER["World Geodetic System 1984 (G730)"],
+        MEMBER["World Geodetic System 1984 (G873)"],
+        MEMBER["World Geodetic System 1984 (G1150)"],
+        MEMBER["World Geodetic System 1984 (G1674)"],
+        MEMBER["World Geodetic System 1984 (G1762)"],
         ELLIPSOID["WGS 84",6378137,298.257223563,
-            LENGTHUNIT["metre",1]]],
+            LENGTHUNIT["metre",1]],
+        ENSEMBLEACCURACY[2.0]],
     PRIMEM["Greenwich",0,
         ANGLEUNIT["degree",0.0174532925199433]],
     CS[ellipsoidal,2],
@@ -59,9 +66,16 @@ GEODCRS["WGS 84",
 Testing projinfo -o WKT2_2019 EPSG:4326
 WKT2:2019 string:
 GEOGCRS["WGS 84",
-    DATUM["World Geodetic System 1984",
+    ENSEMBLE["World Geodetic System 1984 ensemble",
+        MEMBER["World Geodetic System 1984 (Transit)"],
+        MEMBER["World Geodetic System 1984 (G730)"],
+        MEMBER["World Geodetic System 1984 (G873)"],
+        MEMBER["World Geodetic System 1984 (G1150)"],
+        MEMBER["World Geodetic System 1984 (G1674)"],
+        MEMBER["World Geodetic System 1984 (G1762)"],
         ELLIPSOID["WGS 84",6378137,298.257223563,
-            LENGTHUNIT["metre",1]]],
+            LENGTHUNIT["metre",1]],
+        ENSEMBLEACCURACY[2.0]],
     PRIMEM["Greenwich",0,
         ANGLEUNIT["degree",0.0174532925199433]],
     CS[ellipsoidal,2],
@@ -102,9 +116,16 @@ GEODCRS["WGS 84",
 
 WKT2:2019 string:
 GEOGCRS["WGS 84",
-    DATUM["World Geodetic System 1984",
+    ENSEMBLE["World Geodetic System 1984 ensemble",
+        MEMBER["World Geodetic System 1984 (Transit)"],
+        MEMBER["World Geodetic System 1984 (G730)"],
+        MEMBER["World Geodetic System 1984 (G873)"],
+        MEMBER["World Geodetic System 1984 (G1150)"],
+        MEMBER["World Geodetic System 1984 (G1674)"],
+        MEMBER["World Geodetic System 1984 (G1762)"],
         ELLIPSOID["WGS 84",6378137,298.257223563,
-            LENGTHUNIT["metre",1]]],
+            LENGTHUNIT["metre",1]],
+        ENSEMBLEACCURACY[2.0]],
     PRIMEM["Greenwich",0,
         ANGLEUNIT["degree",0.0174532925199433]],
     CS[ellipsoidal,2],
@@ -142,13 +163,61 @@ PROJJSON:
   "$schema": "https://proj.org/schemas/v0.2/projjson.schema.json",
   "type": "GeographicCRS",
   "name": "WGS 84",
-  "datum": {
-    "type": "GeodeticReferenceFrame",
-    "name": "World Geodetic System 1984",
+  "datum_ensemble": {
+    "name": "World Geodetic System 1984 ensemble",
+    "members": [
+      {
+        "name": "World Geodetic System 1984 (Transit)",
+        "id": {
+          "authority": "EPSG",
+          "code": 1166
+        }
+      },
+      {
+        "name": "World Geodetic System 1984 (G730)",
+        "id": {
+          "authority": "EPSG",
+          "code": 1152
+        }
+      },
+      {
+        "name": "World Geodetic System 1984 (G873)",
+        "id": {
+          "authority": "EPSG",
+          "code": 1153
+        }
+      },
+      {
+        "name": "World Geodetic System 1984 (G1150)",
+        "id": {
+          "authority": "EPSG",
+          "code": 1154
+        }
+      },
+      {
+        "name": "World Geodetic System 1984 (G1674)",
+        "id": {
+          "authority": "EPSG",
+          "code": 1155
+        }
+      },
+      {
+        "name": "World Geodetic System 1984 (G1762)",
+        "id": {
+          "authority": "EPSG",
+          "code": 1156
+        }
+      }
+    ],
     "ellipsoid": {
       "name": "WGS 84",
       "semi_major_axis": 6378137,
       "inverse_flattening": 298.257223563
+    },
+    "accuracy": "2.0",
+    "id": {
+      "authority": "EPSG",
+      "code": 6326
     }
   },
   "coordinate_system": {
@@ -1023,9 +1092,16 @@ PROJ.4 string:
 WKT2:2019 string:
 PROJCRS["WGS 84 / UTM zone 31N",
     BASEGEOGCRS["WGS 84",
-        DATUM["World Geodetic System 1984",
+        ENSEMBLE["World Geodetic System 1984 ensemble",
+            MEMBER["World Geodetic System 1984 (Transit)"],
+            MEMBER["World Geodetic System 1984 (G730)"],
+            MEMBER["World Geodetic System 1984 (G873)"],
+            MEMBER["World Geodetic System 1984 (G1150)"],
+            MEMBER["World Geodetic System 1984 (G1674)"],
+            MEMBER["World Geodetic System 1984 (G1762)"],
             ELLIPSOID["WGS 84",6378137,298.257223563,
-                LENGTHUNIT["metre",1]]],
+                LENGTHUNIT["metre",1]],
+            ENSEMBLEACCURACY[2.0]],
         PRIMEM["Greenwich",0,
             ANGLEUNIT["degree",0.0174532925199433]],
         ID["EPSG",4979]],
@@ -1184,6 +1260,27 @@ DATUM["World Geodetic System 1984",
         LENGTHUNIT["metre",1]],
     ID["EPSG",6326]]
 
+Testing -k ensemble WGS84
+WKT2:2019 string:
+ENSEMBLE["World Geodetic System 1984 ensemble",
+    MEMBER["World Geodetic System 1984 (Transit)",
+        ID["EPSG",1166]],
+    MEMBER["World Geodetic System 1984 (G730)",
+        ID["EPSG",1152]],
+    MEMBER["World Geodetic System 1984 (G873)",
+        ID["EPSG",1153]],
+    MEMBER["World Geodetic System 1984 (G1150)",
+        ID["EPSG",1154]],
+    MEMBER["World Geodetic System 1984 (G1674)",
+        ID["EPSG",1155]],
+    MEMBER["World Geodetic System 1984 (G1762)",
+        ID["EPSG",1156]],
+    ELLIPSOID["WGS 84",6378137,298.257223563,
+        LENGTHUNIT["metre",1],
+        ID["EPSG",7030]],
+    ENSEMBLEACCURACY[2.0],
+    ID["EPSG",6326]]
+
 Testing -k operation EPSG:8457 -o PROJ -q
 +proj=pipeline
   +step +proj=axisswap +order=2,1
@@ -1198,9 +1295,23 @@ Testing -k operation EPSG:8457 -o PROJ -q
 
 Testing D_WGS_1984
 WKT2:2019 string:
-DATUM["World Geodetic System 1984",
+ENSEMBLE["World Geodetic System 1984 ensemble",
+    MEMBER["World Geodetic System 1984 (Transit)",
+        ID["EPSG",1166]],
+    MEMBER["World Geodetic System 1984 (G730)",
+        ID["EPSG",1152]],
+    MEMBER["World Geodetic System 1984 (G873)",
+        ID["EPSG",1153]],
+    MEMBER["World Geodetic System 1984 (G1150)",
+        ID["EPSG",1154]],
+    MEMBER["World Geodetic System 1984 (G1674)",
+        ID["EPSG",1155]],
+    MEMBER["World Geodetic System 1984 (G1762)",
+        ID["EPSG",1156]],
     ELLIPSOID["WGS 84",6378137,298.257223563,
-        LENGTHUNIT["metre",1]],
+        LENGTHUNIT["metre",1],
+        ID["EPSG",7030]],
+    ENSEMBLEACCURACY[2.0],
     ID["EPSG",6326]]
 
 Testing -k datum D_WGS_1984
diff --git a/test/unit/test_c_api.cpp b/test/unit/test_c_api.cpp
index 5da6b369..a7c1eb53 100644
--- a/test/unit/test_c_api.cpp
+++ b/test/unit/test_c_api.cpp
@@ -845,6 +845,13 @@ TEST_F(CApi, proj_create_from_database) {
         EXPECT_EQ(proj_get_type(datum), PJ_TYPE_GEODETIC_REFERENCE_FRAME);
     }
     {
+        auto ensemble = proj_create_from_database(
+            m_ctxt, "EPSG", "6326", PJ_CATEGORY_DATUM_ENSEMBLE, false, nullptr);
+        ASSERT_NE(ensemble, nullptr);
+        ObjectKeeper keeper(ensemble);
+        EXPECT_EQ(proj_get_type(ensemble), PJ_TYPE_DATUM_ENSEMBLE);
+    }
+    {
         // International Terrestrial Reference Frame 2008
         auto datum = proj_create_from_database(
             m_ctxt, "EPSG", "1061", PJ_CATEGORY_DATUM, false, nullptr);
@@ -4841,9 +4848,16 @@ TEST_F(CApi, proj_create_derived_geographic_crs) {
     const char *expected_wkt =
         "GEOGCRS[\"my rotated CRS\",\n"
         "    BASEGEOGCRS[\"WGS 84\",\n"
-        "        DATUM[\"World Geodetic System 1984\",\n"
+        "        ENSEMBLE[\"World Geodetic System 1984 ensemble\",\n"
+        "            MEMBER[\"World Geodetic System 1984 (Transit)\"],\n"
+        "            MEMBER[\"World Geodetic System 1984 (G730)\"],\n"
+        "            MEMBER[\"World Geodetic System 1984 (G873)\"],\n"
+        "            MEMBER[\"World Geodetic System 1984 (G1150)\"],\n"
+        "            MEMBER[\"World Geodetic System 1984 (G1674)\"],\n"
+        "            MEMBER[\"World Geodetic System 1984 (G1762)\"],\n"
         "            ELLIPSOID[\"WGS 84\",6378137,298.257223563,\n"
-        "                LENGTHUNIT[\"metre\",1]]],\n"
+        "                LENGTHUNIT[\"metre\",1]],\n"
+        "            ENSEMBLEACCURACY[2.0]],\n"
         "        PRIMEM[\"Greenwich\",0,\n"
         "            ANGLEUNIT[\"degree\",0.0174532925199433]]],\n"
         "    DERIVINGCONVERSION[\"Pole rotation (GRIB convention)\",\n"
diff --git a/test/unit/test_factory.cpp b/test/unit/test_factory.cpp
index 1005d49b..8e9b7ab6 100644
--- a/test/unit/test_factory.cpp
+++ b/test/unit/test_factory.cpp
@@ -531,8 +531,10 @@ TEST(factory, AuthorityFactory_createGeodeticCRS_geographic2D) {
     EXPECT_EQ(gcrs->identifiers()[0]->code(), "4326");
     EXPECT_EQ(*(gcrs->identifiers()[0]->codeSpace()), "EPSG");
     EXPECT_EQ(*(gcrs->name()->description()), "WGS 84");
-    EXPECT_TRUE(
-        gcrs->datum()->isEquivalentTo(factory->createDatum("6326").get()));
+    ASSERT_TRUE(gcrs->datum() == nullptr);
+    ASSERT_TRUE(gcrs->datumEnsemble() != nullptr);
+    EXPECT_TRUE(gcrs->datumEnsemble()->isEquivalentTo(
+        factory->createDatumEnsemble("6326").get()));
     EXPECT_TRUE(gcrs->coordinateSystem()->isEquivalentTo(
         factory->createCoordinateSystem("6422").get()));
     auto domain = crs->domains()[0];
@@ -566,8 +568,10 @@ TEST(factory, AuthorityFactory_createGeodeticCRS_geographic3D) {
     EXPECT_EQ(gcrs->identifiers()[0]->code(), "4979");
     EXPECT_EQ(*(gcrs->identifiers()[0]->codeSpace()), "EPSG");
     EXPECT_EQ(*(gcrs->name()->description()), "WGS 84");
-    EXPECT_TRUE(
-        gcrs->datum()->isEquivalentTo(factory->createDatum("6326").get()));
+    ASSERT_TRUE(gcrs->datum() == nullptr);
+    ASSERT_TRUE(gcrs->datumEnsemble() != nullptr);
+    EXPECT_TRUE(gcrs->datumEnsemble()->isEquivalentTo(
+        factory->createDatumEnsemble("6326").get()));
     EXPECT_TRUE(gcrs->coordinateSystem()->isEquivalentTo(
         factory->createCoordinateSystem("6423").get()));
 }
@@ -582,8 +586,10 @@ TEST(factory, AuthorityFactory_createGeodeticCRS_geocentric) {
     EXPECT_EQ(crs->identifiers()[0]->code(), "4978");
     EXPECT_EQ(*(crs->identifiers()[0]->codeSpace()), "EPSG");
     EXPECT_EQ(*(crs->name()->description()), "WGS 84");
-    EXPECT_TRUE(
-        crs->datum()->isEquivalentTo(factory->createDatum("6326").get()));
+    ASSERT_TRUE(crs->datum() == nullptr);
+    ASSERT_TRUE(crs->datumEnsemble() != nullptr);
+    EXPECT_TRUE(crs->datumEnsemble()->isEquivalentTo(
+        factory->createDatumEnsemble("6326").get()));
     EXPECT_TRUE(crs->coordinateSystem()->isEquivalentTo(
         factory->createCoordinateSystem("6500").get()));
 }
@@ -613,6 +619,20 @@ TEST(factory, AuthorityFactory_createVerticalCRS) {
 
 // ---------------------------------------------------------------------------
 
+TEST(factory, AuthorityFactory_createVerticalCRS_with_datum_ensemble) {
+    auto factory = AuthorityFactory::create(DatabaseContext::create(), "EPSG");
+    EXPECT_THROW(factory->createVerticalCRS("-1"),
+                 NoSuchAuthorityCodeException);
+
+    auto crs = factory->createVerticalCRS("9451"); // BI height
+    ASSERT_TRUE(crs->datum() == nullptr);
+    ASSERT_TRUE(crs->datumEnsemble() != nullptr);
+    EXPECT_TRUE(crs->datumEnsemble()->isEquivalentTo(
+        factory->createDatumEnsemble("1288").get()));
+}
+
+// ---------------------------------------------------------------------------
+
 TEST(factory, AuthorityFactory_createConversion) {
     auto factory = AuthorityFactory::create(DatabaseContext::create(), "EPSG");
     EXPECT_THROW(factory->createConversion("-1"), NoSuchAuthorityCodeException);
@@ -3166,6 +3186,29 @@ TEST(factory, createObjectsFromName) {
             .size(),
         1U);
 
+    {
+        auto res = factory->createObjectsFromName(
+            "World Geodetic System 1984 ensemble",
+            {AuthorityFactory::ObjectType::DATUM_ENSEMBLE}, false);
+        EXPECT_EQ(res.size(), 1U);
+        if (!res.empty()) {
+            EXPECT_EQ(res.front()->getEPSGCode(), 6326);
+            EXPECT_TRUE(dynamic_cast<DatumEnsemble *>(res.front().get()) !=
+                        nullptr);
+        }
+    }
+
+    {
+        auto res = factory->createObjectsFromName(
+            "World Geodetic System 1984 ensemble", {}, false);
+        EXPECT_EQ(res.size(), 1U);
+        if (!res.empty()) {
+            EXPECT_EQ(res.front()->getEPSGCode(), 6326);
+            EXPECT_TRUE(dynamic_cast<DatumEnsemble *>(res.front().get()) !=
+                        nullptr);
+        }
+    }
+
     const auto types = std::vector<AuthorityFactory::ObjectType>{
         AuthorityFactory::ObjectType::PRIME_MERIDIAN,
         AuthorityFactory::ObjectType::ELLIPSOID,
@@ -3187,6 +3230,7 @@ TEST(factory, createObjectsFromName) {
         AuthorityFactory::ObjectType::CONVERSION,
         AuthorityFactory::ObjectType::TRANSFORMATION,
         AuthorityFactory::ObjectType::CONCATENATED_OPERATION,
+        AuthorityFactory::ObjectType::DATUM_ENSEMBLE,
     };
     for (const auto type : types) {
         factory->createObjectsFromName("i_dont_exist", {type}, false, 1);
diff --git a/test/unit/test_io.cpp b/test/unit/test_io.cpp
index 555d1159..3d8df998 100644
--- a/test/unit/test_io.cpp
+++ b/test/unit/test_io.cpp
@@ -10444,6 +10444,14 @@ TEST(io, createFromUserInput) {
                  ParsingException);
     EXPECT_THROW(createFromUserInput("foobar + EGM96 height", dbContext),
                  ParsingException);
+
+    {
+        auto obj = createFromUserInput("World Geodetic System 1984 ensemble",
+                                       dbContext);
+        auto ensemble = nn_dynamic_pointer_cast<DatumEnsemble>(obj);
+        ASSERT_TRUE(ensemble != nullptr);
+        EXPECT_EQ(ensemble->identifiers().size(), 1U);
+    }
 }
 
 // ---------------------------------------------------------------------------