kylebarron commented on code in PR #8225: URL: https://github.com/apache/arrow-rs/pull/8225#discussion_r2299561358
########## parquet/src/geospatial/statistics.rs: ########## @@ -0,0 +1,290 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Geospatial statistics for Parquet files. +//! +//! This module provides functionality for working with geospatial statistics in Parquet files. +//! It includes support for bounding boxes and geospatial statistics in column chunk metadata. + +use crate::format as parquet; +use crate::format::GeospatialStatistics as TGeospatialStatistics; +use crate::errors::Result; + +// ---------------------------------------------------------------------- +// Bounding Box + +/// Represents a 2D/3D bounding box with optional M-coordinate support. +/// +/// A bounding box defines the spatial extent of geospatial data by specifying +/// minimum and maximum coordinates along each axis. This struct supports: +/// - 2D coordinates (x, y) which are always required +/// - Optional 3D coordinates (z) for elevation/height data +/// - Optional M-coordinates for measured values (e.g., distance along a route) +/// +/// # Examples +/// +/// ``` +/// use parquet::geospatial::statistics::BoundingBox; +/// +/// // 2D bounding box +/// let bbox_2d = BoundingBox::new(0.0, 0.0, 100.0, 100.0, None, None, None, None); +/// +/// // 3D bounding box with elevation +/// let bbox_3d = BoundingBox::new(0.0, 0.0, 100.0, 100.0, Some(0.0), Some(1000.0), None, None); +/// ``` +#[derive(Clone, Debug, PartialEq)] +pub struct BoundingBox { + /// Minimum X coordinate (longitude or easting) + xmin: f64, + /// Minimum Y coordinate (latitude or northing) + ymin: f64, + /// Maximum X coordinate (longitude or easting) + xmax: f64, + /// Maximum Y coordinate (latitude or northing) + ymax: f64, + /// Minimum Z coordinate (elevation/height), if present + zmin: Option<f64>, + /// Maximum Z coordinate (elevation/height), if present + zmax: Option<f64>, + /// Minimum M coordinate (measured value), if present + mmin: Option<f64>, + /// Maximum M coordinate (measured value), if present + mmax: Option<f64>, +} + +impl BoundingBox { + /// Creates a new bounding box with the specified coordinates. + /// + /// # Arguments + /// + /// * `xmin` - Minimum X coordinate + /// * `ymin` - Minimum Y coordinate + /// * `xmax` - Maximum X coordinate + /// * `ymax` - Maximum Y coordinate + /// * `zmin` - Optional minimum Z coordinate + /// * `zmax` - Optional maximum Z coordinate + /// * `mmin` - Optional minimum M coordinate + /// * `mmax` - Optional maximum M coordinate + /// + /// # Returns + /// + /// A new `BoundingBox` instance with the specified coordinates. + pub fn new(xmin: f64, ymin: f64, xmax: f64, ymax: f64, zmin: Option<f64>, zmax: Option<f64>, mmin: Option<f64>, mmax: Option<f64>) -> Self { + Self { xmin, ymin, xmax, ymax, zmin, zmax, mmin, mmax } + } +} + +// ---------------------------------------------------------------------- +// Geospatial Statistics + +/// Represents geospatial statistics for a Parquet column or dataset. +/// +/// This struct contains metadata about the spatial characteristics of geospatial data, +/// including bounding box information and the types of geospatial geometries present. +/// It's used to optimize spatial queries and provide spatial context for data analysis. +/// +/// # Examples +/// +/// ``` +/// use parquet::geospatial::statistics::{GeospatialStatistics, BoundingBox}; +/// +/// // Empty statistics +/// let empty_stats = GeospatialStatistics::new_empty(); +/// +/// // Statistics with bounding box +/// let bbox = BoundingBox::new(0.0, 0.0, 100.0, 100.0, None, None, None, None); +/// let stats = GeospatialStatistics::new(Some(bbox), Some(vec![1, 2, 3])); +/// ``` +#[derive(Clone, Debug, PartialEq)] +pub struct GeospatialStatistics { + /// Optional bounding box encompassing all geospatial data + bbox: Option<BoundingBox>, + /// Optional list of geospatial geometry type identifiers + /// + /// Common values include: + /// - 1: Point + /// - 2: LineString + /// - 3: Polygon + /// - 4: MultiPoint + /// - 5: MultiLineString + /// - 6: MultiPolygon + /// - 7: GeometryCollection + geospatial_types: Option<Vec<i32>>, +} + +impl GeospatialStatistics { + /// Creates a new empty geospatial statistics instance. + /// + /// This is useful when no spatial information is available or when + /// creating a placeholder for statistics that will be populated later. + /// + /// # Returns + /// + /// A `GeospatialStatistics` instance with no bounding box or type information. + pub fn new_empty() -> Self { Review Comment: Maybe cleaner to remove this and just implement `Default`? -- This is an automated message from the Apache Git Service. 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