proj_create_crs_to_crs_from_pj(): add ACCURACY and ALLOW_BALLPARK options

3 files changed, 85 insertions, 0 deletions

diff --git a/docs/source/development/reference/functions.rst b/docs/source/development/reference/functions.rst
index 08b3e669..34fe59ed 100644
--- a/docs/source/development/reference/functions.rst
+++ b/docs/source/development/reference/functions.rst
@@ -195,6 +195,11 @@ paragraph for more details.
       If authority is a non-empty string different of ``any``, then coordinate operations
       will be searched only in that authority namespace (e.g ``EPSG``).
 
+    - ACCURACY=value: to set the minimum desired accuracy (in metres) of the
+      candidate coordinate operations.
+
+    - ALLOW_BALLPARK=YES/NO: can be set to NO to disallow the use of
+      :term:`Ballpark transformation` in the candidate coordinate operations.
 
 .. doxygenfunction:: proj_normalize_for_visualization
    :project: doxygen_api
diff --git a/src/4D_api.cpp b/src/4D_api.cpp
index 7423240f..909c3c32 100644
--- a/src/4D_api.cpp
+++ b/src/4D_api.cpp
@@ -1302,10 +1302,24 @@ PJ  *proj_create_crs_to_crs_from_pj (PJ_CONTEXT *ctx, const PJ *source_crs, cons
     }
 
     const char* authority = nullptr;
+    double accuracy = -1;
+    bool allowBallparkTransformations = true;
     for (auto iter = options; iter && iter[0]; ++iter) {
         const char *value;
         if ((value = getOptionValue(*iter, "AUTHORITY="))) {
             authority = value;
+        } else if ((value = getOptionValue(*iter, "ACCURACY="))) {
+            accuracy = pj_atof(value);
+        } else if ((value = getOptionValue(*iter, "ALLOW_BALLPARK="))) {
+            if( ci_equal(value, "yes") )
+                allowBallparkTransformations = true;
+            else if( ci_equal(value, "no") )
+                allowBallparkTransformations = false;
+            else {
+                ctx->logger(ctx->logger_app_data, PJ_LOG_ERROR,
+                            "Invalid value for ALLOW_BALLPARK option.");
+                return nullptr;
+            }
         } else {
             std::string msg("Unknown option :");
             msg += *iter;
@@ -1319,6 +1333,14 @@ PJ  *proj_create_crs_to_crs_from_pj (PJ_CONTEXT *ctx, const PJ *source_crs, cons
         return nullptr;
     }
 
+    proj_operation_factory_context_set_allow_ballpark_transformations(
+        ctx, operation_ctx, allowBallparkTransformations);
+
+    if( accuracy >= 0 ) {
+        proj_operation_factory_context_set_desired_accuracy(ctx, operation_ctx,
+                                                            accuracy);
+    }
+
     if( area && area->bbox_set ) {
         proj_operation_factory_context_set_area_of_interest(
                                             ctx,
diff --git a/test/unit/test_c_api.cpp b/test/unit/test_c_api.cpp
index c417371d..e54c6fa7 100644
--- a/test/unit/test_c_api.cpp
+++ b/test/unit/test_c_api.cpp
@@ -4196,6 +4196,64 @@ TEST_F(CApi, proj_create_crs_to_crs_from_pj) {
 
 // ---------------------------------------------------------------------------
 
+TEST_F(CApi, proj_create_crs_to_crs_from_pj_accuracy_filter) {
+
+    auto src = proj_create(m_ctxt, "EPSG:4326"); // WGS 84
+    ObjectKeeper keeper_src(src);
+    ASSERT_NE(src, nullptr);
+
+    auto dst = proj_create(m_ctxt, "EPSG:4258"); // ETRS89
+    ObjectKeeper keeper_dst(dst);
+    ASSERT_NE(dst, nullptr);
+
+    // No options
+    {
+        auto P =
+            proj_create_crs_to_crs_from_pj(m_ctxt, src, dst, nullptr, nullptr);
+        ObjectKeeper keeper_P(P);
+        ASSERT_NE(P, nullptr);
+    }
+
+    {
+        const char *const options[] = {"ACCURACY=0.05", nullptr};
+        auto P =
+            proj_create_crs_to_crs_from_pj(m_ctxt, src, dst, nullptr, options);
+        ObjectKeeper keeper_P(P);
+        ASSERT_EQ(P, nullptr);
+    }
+}
+
+// ---------------------------------------------------------------------------
+
+TEST_F(CApi, proj_create_crs_to_crs_from_pj_ballpark_filter) {
+
+    auto src = proj_create(m_ctxt, "EPSG:4267"); // NAD 27
+    ObjectKeeper keeper_src(src);
+    ASSERT_NE(src, nullptr);
+
+    auto dst = proj_create(m_ctxt, "EPSG:4258"); // ETRS89
+    ObjectKeeper keeper_dst(dst);
+    ASSERT_NE(dst, nullptr);
+
+    // No options
+    {
+        auto P =
+            proj_create_crs_to_crs_from_pj(m_ctxt, src, dst, nullptr, nullptr);
+        ObjectKeeper keeper_P(P);
+        ASSERT_NE(P, nullptr);
+    }
+
+    {
+        const char *const options[] = {"ALLOW_BALLPARK=NO", nullptr};
+        auto P =
+            proj_create_crs_to_crs_from_pj(m_ctxt, src, dst, nullptr, options);
+        ObjectKeeper keeper_P(P);
+        ASSERT_EQ(P, nullptr);
+    }
+}
+
+// ---------------------------------------------------------------------------
+
 static void
 check_axis_is_latitude(PJ_CONTEXT *ctx, PJ *cs, int axis_number,
                        const char *unit_name = "degree",