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feat: implement ST_Expand #672

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feat: implement ST_Expand #672

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78 changes: 78 additions & 0 deletions src/spatial/modules/main/spatial_functions_scalar.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3003,6 +3003,83 @@ struct ST_Dump {
}
};


//======================================================================================================================
// ST_Expand
//======================================================================================================================

struct ST_Expand {

//------------------------------------------------------------------------------------------------------------------
// GEOMETRY
//------------------------------------------------------------------------------------------------------------------
static void Execute(DataChunk &args, ExpressionState &state, Vector &result) {
auto &lstate = LocalState::ResetAndGet(state);

BinaryExecutor::Execute<string_t, double, string_t>(args.data[0], args.data[1], result, args.size(), [&](const string_t &blob, double distance) {
sgl::geometry geom;
lstate.Deserialize(blob, geom);
auto bbox = sgl::extent_xy::smallest();

if (sgl::ops::get_total_extent_xy(geom, bbox) == 0) {
const sgl::geometry empty(sgl::geometry_type::GEOMETRY_COLLECTION, false, false);
return lstate.Serialize(result, empty);
} else {
sgl::geometry expanded(sgl::geometry_type::POLYGON, false, false);
const auto min_x = bbox.min.x - distance;
const auto min_y = bbox.min.y - distance;
const auto max_x = bbox.max.x + distance;
const auto max_y = bbox.max.y + distance;
const double buffer[10] = {min_x, min_y, min_x, max_y, max_x, max_y, max_x, min_y, min_x, min_y};

sgl::geometry ring(sgl::geometry_type::LINESTRING, false, false);
ring.set_vertex_array(buffer, 5);
expanded.append_part(&ring);
return lstate.Serialize(result, expanded);
}
});
}

//------------------------------------------------------------------------------------------------------------------
// Documentation
//------------------------------------------------------------------------------------------------------------------
static constexpr auto DESCRIPTION = R"(
Expand the input geometry by the specified distance, returning a polygon.

`geom` is the input geometry.

`distance` is the target distance for the expansion, using the same units as the input geometry.

This is a planar operation and will not take into account the curvature of the earth.
)";
static constexpr auto EXAMPLE = R"(
SELECT ST_AsText(ST_Expand(ST_GeomFromText('POINT(20 30)'), 0.1));
)";

//------------------------------------------------------------------------------------------------------------------
// Register
//------------------------------------------------------------------------------------------------------------------
static void Register(ExtensionLoader &loader) {
FunctionBuilder::RegisterScalar(loader, "ST_Expand", [](ScalarFunctionBuilder &func) {
func.AddVariant([](ScalarFunctionVariantBuilder &variant) {
variant.AddParameter("geom", GeoTypes::GEOMETRY());
variant.AddParameter("distance", LogicalType::DOUBLE);
variant.SetReturnType(GeoTypes::GEOMETRY());

variant.SetInit(LocalState::Init);
variant.SetFunction(Execute);
});

func.SetDescription(DESCRIPTION);
func.SetExample(EXAMPLE);

func.SetTag("ext", "spatial");
func.SetTag("category", "property");
});
}
};


//======================================================================================================================
// ST_Extent
//======================================================================================================================
Expand Down Expand Up @@ -9279,6 +9356,7 @@ void RegisterSpatialScalarFunctions(ExtensionLoader &loader) {
ST_DistanceWithin::Register(loader);
ST_Dump::Register(loader);
ST_EndPoint::Register(loader);
ST_Expand::Register(loader);
ST_Extent::Register(loader);
ST_Extent_Approx::Register(loader);
// Op_IntersectApprox::Register(loader);
Expand Down
46 changes: 46 additions & 0 deletions test/sql/geometry/st_expand.test
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Original file line number Diff line number Diff line change
@@ -0,0 +1,46 @@
require spatial

query I
SELECT ST_AsText(ST_Expand(ST_MakePoint(153.0, -38.0), 0.001));
----
POLYGON ((152.999 -38.001, 152.999 -37.999, 153.001 -37.999, 153.001 -38.001, 152.999 -38.001))

query I
SELECT ST_AsText(ST_Expand(ST_MakePoint(153.0, -38.0), 0.0));
----
POLYGON ((153 -38, 153 -38, 153 -38, 153 -38, 153 -38))

query I
SELECT ST_AsText(ST_Expand(ST_GeomFromText('POINT(20 30)'), 0.001));
----
POLYGON ((19.999 29.999, 19.999 30.001, 20.001 30.001, 20.001 29.999, 19.999 29.999))

query I
SELECT ST_AsText(ST_Expand(ST_GeomFromText('GEOMETRYCOLLECTION(POINT(20 30))'), 0.001));
----
POLYGON ((19.999 29.999, 19.999 30.001, 20.001 30.001, 20.001 29.999, 19.999 29.999))

query I
SELECT ST_AsText(ST_Expand(ST_GeomFromText('POLYGON((20 30, 21 30, 21 31, 20 31, 20 30))'), 0.1));
----
POLYGON ((19.9 29.9, 19.9 31.1, 21.1 31.1, 21.1 29.9, 19.9 29.9))

query I
SELECT ST_AsText(ST_Expand(ST_GeomFromText('POLYGON((20 30, 21 30, 22 32, 21 31, 20 31, 20 30))'), 0.1));
----
POLYGON ((19.9 29.9, 19.9 32.1, 22.1 32.1, 22.1 29.9, 19.9 29.9))

query I
SELECT ST_AsText(ST_Expand(ST_MakeEnvelope(20, 30, 21, 31), 0.1));
----
POLYGON ((19.9 29.9, 19.9 31.1, 21.1 31.1, 21.1 29.9, 19.9 29.9))

query I
SELECT ST_AsText(ST_Expand(ST_MakeEnvelope(153.2, -38.8, 153.5, -38.7), 0.0));
----
POLYGON ((153.2 -38.8, 153.2 -38.7, 153.5 -38.7, 153.5 -38.8, 153.2 -38.8))

query I
SELECT ST_AsText(ST_Expand(ST_GeomFromText('GEOMETRYCOLLECTION EMPTY'), 0.001));
----
GEOMETRYCOLLECTION EMPTY
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