feat(vortex-spatial): support GeoArrow Geometry unions

vortex-spatial/Cargo.toml

@@ -15,6 +15,7 @@ version.workspace = true
 
 [dependencies]
 arrow-array = { workspace = true }
+arrow-buffer = { workspace = true }
 arrow-schema = { workspace = true }
 geo = { workspace = true }
 geo-traits = { workspace = true }
@@ -25,6 +26,7 @@ prost = { workspace = true }
 vortex-array = { workspace = true }
 vortex-arrow = { workspace = true }
 vortex-buffer = { workspace = true }
+vortex-dense-union = { workspace = true }
 vortex-error = { workspace = true }
 vortex-mask = { workspace = true }
 vortex-session = { workspace = true }

vortex-spatial/src/aggregate_fn/aabb.rs

@@ -3,6 +3,7 @@
 
 //! The 2D axis-aligned bounding-box (AABB) aggregate for native geometry columns.
 
+use geo::BoundingRect;
 use geo::Rect as SpatialRect;
 use vortex_array::ArrayRef;
 use vortex_array::Columnar;
@@ -23,12 +24,14 @@ use vortex_error::vortex_err;
 use vortex_session::VortexSession;
 use vortex_session::registry::CachedId;
 
+use crate::extension::Geometry;
 use crate::extension::Rect;
 use crate::extension::SpatialMetadata;
 use crate::extension::box_storage_dtype;
 use crate::extension::coordinate::Dimension;
 use crate::extension::coordinate::box_corners;
 use crate::extension::coordinate::ordinates;
+use crate::extension::decode_mixed_geometries;
 use crate::extension::flatten_coordinates;
 use crate::extension::is_native_geometry;
 
@@ -205,6 +208,18 @@ impl AggregateFnVTable for GeometryAabb {
         // non-nullable case already costs nothing (the all-true mask makes `filter` a no-op).
         let valid = array.validity()?.execute_mask(array.len(), ctx)?;
         let array = array.filter(valid)?;
+        if array
+            .dtype()
+            .as_extension_opt()
+            .is_some_and(|ext| ext.is::<Geometry>())
+        {
+            for geometry in decode_mixed_geometries(&array, ctx)? {
+                if let Some(rect) = geometry.bounding_rect() {
+                    partial.merge(rect);
+                }
+            }
+            return Ok(());
+        }
         // Null rows are gone, so every coordinate below belongs to a present geometry — the
         // `unmasked_field_by_name` reads are therefore safe. Min/max the raw x/y buffers directly:
         // cheap, and avoids `to_geometry`'s panic on empty points (which decoding would hit).