Merge pull request #1783 from joto/add-create-multipoint

Add function to create multipoint geometry

Author: lonvia

src/geom-from-osm.cpp

@@ -95,6 +95,37 @@ geometry_t create_polygon(osmium::Way const &way)
     return geom;
 }
 
+void create_multipoint(geometry_t *geom, osmium::memory::Buffer const &buffer)
+{
+    auto nodes = buffer.select<osmium::Node>();
+    if (nodes.size() == 1) {
+        auto const location = nodes.cbegin()->location();
+        if (location.valid()) {
+            geom->set<point_t>() = point_t{location};
+        } else {
+            geom->reset();
+        }
+    } else {
+        auto &multiline = geom->set<multipoint_t>();
+        for (auto const &node : nodes) {
+            auto const location = node.location();
+            if (location.valid()) {
+                multiline.add_geometry(point_t{location});
+            }
+        }
+        if (multiline.num_geometries() == 0) {
+            geom->reset();
+        }
+    }
+}
+
+geometry_t create_multipoint(osmium::memory::Buffer const &buffer)
+{
+    geometry_t geom{};
+    create_multipoint(&geom, buffer);
+    return geom;
+}
+
 void create_multilinestring(geometry_t *geom,
                             osmium::memory::Buffer const &buffer,
                             bool force_multi)

src/geom-from-osm.hpp

@@ -89,6 +89,33 @@ void create_polygon(geometry_t *geom, osmium::Way const &way);
  */
 [[nodiscard]] geometry_t create_polygon(osmium::Way const &way);
 
+/**
+ * Create a multipoint geometry from a bunch of nodes (usually this would be
+ * used for member nodes of a relation). The result is multipoint geometry
+ * (or a point geometry if there is only one point).
+ *
+ * If there are no (valid) points, a null geometry is returned.
+ *
+ * \param geom Pointer to an existing geometry which will be used as output.
+ * \param ways Buffer containing all the input ways. Object types other than
+ *             ways in the buffer are ignored.
+ */
+void create_multipoint(geometry_t *geom, osmium::memory::Buffer const &buffer);
+
+/**
+ * Create a multipoint geometry from a bunch of nodes (usually this would be
+ * used for member nodes of a relation). The result is multipoint geometry
+ * (or a point geometry if there is only one point).
+ *
+ * If there are no (valid) points, a null geometry is returned.
+ *
+ * \param ways Buffer containing all the input nodes. Object types other than
+ *             nodes in the buffer are ignored.
+ * \returns The created geometry.
+ */
+[[nodiscard]] geometry_t
+create_multipoint(osmium::memory::Buffer const &buffer);
+
 /**
  * Create a multilinestring geometry from a bunch of ways (usually this
  * would be used for member ways of a relation). The result is always a

src/output-flex.cpp

@@ -78,6 +78,7 @@ TRAMPOLINE(app_get_bbox, get_bbox)
 TRAMPOLINE(app_as_point, as_point)
 TRAMPOLINE(app_as_linestring, as_linestring)
 TRAMPOLINE(app_as_polygon, as_polygon)
+TRAMPOLINE(app_as_multipoint, as_multipoint)
 TRAMPOLINE(app_as_multilinestring, as_multilinestring)
 TRAMPOLINE(app_as_multipolygon, as_multipolygon)
 TRAMPOLINE(app_as_geometrycollection, as_geometrycollection)
@@ -920,6 +921,25 @@ int output_flex_t::app_as_polygon()
     return 1;
 }
 
+int output_flex_t::app_as_multipoint()
+{
+    check_context_and_state(
+        "as_multipoint", "process_node/relation() functions",
+        m_calling_context != calling_context::process_node &&
+            m_calling_context != calling_context::process_relation);
+
+    auto *geom = create_lua_geometry_object(lua_state());
+
+    if (m_calling_context == calling_context::process_node) {
+        geom::create_point(geom, *m_context_node);
+    } else {
+        m_relation_cache.add_members(middle());
+        geom::create_multipoint(geom, m_relation_cache.members_buffer());
+    }
+
+    return 1;
+}
+
 int output_flex_t::app_as_multilinestring()
 {
     check_context_and_state(
@@ -2099,6 +2119,8 @@ void output_flex_t::init_lua(std::string const &filename)
                         lua_trampoline_app_as_point);
     luaX_add_table_func(lua_state(), "as_polygon",
                         lua_trampoline_app_as_polygon);
+    luaX_add_table_func(lua_state(), "as_multipoint",
+                        lua_trampoline_app_as_multipoint);
     luaX_add_table_func(lua_state(), "as_multilinestring",
                         lua_trampoline_app_as_multilinestring);
     luaX_add_table_func(lua_state(), "as_multipolygon",

src/output-flex.hpp

@@ -156,6 +156,7 @@ class output_flex_t : public output_t
     int app_as_point();
     int app_as_linestring();
     int app_as_polygon();
+    int app_as_multipoint();
     int app_as_multilinestring();
     int app_as_multipolygon();
     int app_as_geometrycollection();

tests/bdd/flex/geometry-multipoint.feature

@@ -0,0 +1,51 @@
+Feature: Creating (multi)point features from nodes and relations
+
+    Scenario:
+        Given the grid
+            | 1 | 2 |   |
+            | 4 |   | 3 |
+            |   | 5 | 6 |
+        And the OSM data
+            """
+            n1 Thighway=bus_stop
+            n5 Thighway=bus_stop
+            w20 Thighway=residential Nn1,n2,n3,n4
+            w21 Thighway=primary Nn4,n5,n6
+            r30 Troute=bus Mn1@
+            r31 Troute=bus Mw21@,n5@,w20@,n1@
+            """
+        And the lua style
+            """
+            local points = osm2pgsql.define_table({
+                name = 'osm2pgsql_test_points',
+                ids = { type = 'any', id_column = 'osm_id', type_column = 'osm_type' },
+                columns = {
+                    { column = 'geom', type = 'geometry', projection = 4326 },
+                }
+            })
+
+            function osm2pgsql.process_node(object)
+                if object.tags.highway == 'bus_stop' then
+                    points:insert({
+                        geom = object:as_multipoint()
+                    })
+                end
+            end
+
+            function osm2pgsql.process_relation(object)
+                if object.tags.route == 'bus' then
+                    points:insert({
+                        geom = object:as_multipoint()
+                    })
+                end
+            end
+            """
+        When running osm2pgsql flex
+
+        Then table osm2pgsql_test_points contains exactly
+            | osm_type | osm_id | ST_GeometryType(geom) | ST_NumGeometries(geom) | ST_AsText(ST_GeometryN(geom, 1)) | ST_AsText(ST_GeometryN(geom, 2)) |
+            | N        | 1      | ST_Point              | 1                      | 1                                | NULL                             |
+            | N        | 5      | ST_Point              | 1                      | 5                                | NULL                             |
+            | R        | 30     | ST_Point              | 1                      | 1                                | NULL                             |
+            | R        | 31     | ST_MultiPoint         | 2                      | 5                                | 1                                |
+

tests/bdd/steps/geometry_factory.py

@@ -101,7 +101,7 @@ def complete_node_list(self, nodes):
 
                 coords = self.grid_node(nid)
                 assert coords is not None, f"Coordinates missing for node {node}"
-                nodes[i] = f"{line} x{coords[0]:f.{self.grid_precision}} y{coords[1]:f.{self.grid_precision}}"
+                nodes[i] = f"{line} x{coords[0]:.{self.grid_precision}f} y{coords[1]:.{self.grid_precision}f}"
 
             todos.discard(nid)
 

tests/bdd/steps/steps_osm_data.py

@@ -38,4 +38,4 @@ def osm_define_data(context, formatted):
     for line in data.split('\n'):
         if line:
             assert line[0] in ('n', 'w', 'r')
-            context.import_data[line[0]].append(line)
+            context.import_data[line[0]].append(line.strip())

tests/test-geom-multipoints.cpp

@@ -67,3 +67,31 @@ TEST_CASE("multipoint_t with several points", "[NoDB]")
     REQUIRE(geometry_n(geom, 2) == geom::geometry_t{std::move(p1)});
     REQUIRE(geometry_n(geom, 3) == geom::geometry_t{std::move(p2)});
 }
+
+TEST_CASE("create_multipoint from OSM data", "[NoDB]")
+{
+    test_buffer_t buffer;
+    buffer.add_node("n10 x1 y0");
+    buffer.add_way("w20 Nn1x1y1,n2x2y1");
+    buffer.add_node("n11 x1 y1");
+    buffer.add_node("n12 x3 y2");
+    buffer.add_way("w21 Nn3x10y10,n4x10y11");
+    buffer.add_node("n13 x3 y1");
+    buffer.add_relation("r30 Mw20@");
+
+    auto const geom = geom::create_multipoint(buffer.buffer());
+
+    REQUIRE(geometry_type(geom) == "MULTIPOINT");
+    REQUIRE(dimension(geom) == 0);
+    REQUIRE(num_geometries(geom) == 4);
+
+    auto const &c = geom.get<geom::multipoint_t>();
+    REQUIRE(c[0] == geom::point_t{1, 0});
+    REQUIRE(c[1] == geom::point_t{1, 1});
+    REQUIRE(c[2] == geom::point_t{3, 2});
+    REQUIRE(c[3] == geom::point_t{3, 1});
+
+    REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(0.0));
+    REQUIRE(centroid(geom) == geom::geometry_t{geom::point_t{2, 1}});
+}