https://github.com/emma-k-alexandra/rtree
An on-disk, Codable R*-Tree for Swift
https://github.com/emma-k-alexandra/rtree
codable data-structures json mit-license r-tree search-trees swift-package-manager trees xcode
Last synced: 1 day ago
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An on-disk, Codable R*-Tree for Swift
- Host: GitHub
- URL: https://github.com/emma-k-alexandra/rtree
- Owner: emma-k-alexandra
- License: mit
- Created: 2019-10-22T19:39:50.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2022-01-29T00:54:28.000Z (over 3 years ago)
- Last Synced: 2025-10-05T11:45:13.511Z (17 days ago)
- Topics: codable, data-structures, json, mit-license, r-tree, search-trees, swift-package-manager, trees, xcode
- Language: Swift
- Homepage:
- Size: 105 KB
- Stars: 24
- Watchers: 1
- Forks: 4
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# RTree
RTree is an on-disk, [`Codable`](https://developer.apple.com/documentation/foundation/archives_and_serialization/encoding_and_decoding_custom_types) R\*-Tree for searching.
RTree is a port of the Rust crate [`Spade`](https://crates.io/crates/spade)'s N-Dimentional R\*-Tree, modified to store the tree on disk rather than in memory. It only can perform inserts and nearest neighbor queries.
## Contents
- [Requirements](#requirements)
- [Installation](#installation)
- [Disclaimer & Warnings](#disclaimer--warnings)
- [Design](#design)
- [Usage](#usage)
- [Getting Started](#getting-started)
- [Dependencies](#dependencies)
- [Contributing](#contributing)
- [Contact](#contact)
- [Acknowledgements](#acknowledgements)
- [License](#license)
## Requirements
- Swift 5.1+
- iOS 13, watchOS 6, macOS 10.15, tvOS 15
## Installation
### Swift Package Manager
```swift
dependencies: [
.package(
name: "RTree",
url: "https://github.com/emma-k-alexandra/RTree.git",
from: "2.2.0"
)
]
```
## Disclaimer & Warnings
RTree performs nearest neighbor searches at the expected speed of a R*-Tree. RTree uses far more space than expected on disk, and inserts are extemely inefficient. RTree does not currently support deletion or updating of records.
## Design
This R\*-Tree is designed to use exclusively Swift, and provide a general interface for doing nearest neighbor queries on N-dimensional objects.
Expect to a implement your own `SpatialObject`-implementing structure and `PointN`-implementing vector type in order to use RTree. For an example, see `RTreeTests.swift` or [Usage](#usage)
## Usage
### Getting started
First, you need a SpatialObject-implementing type to store in the R-Tree. For demonstration purposes, I will implement a 2-dimensional vector and SpatialObject that will store a custom field.
2-dimensional vector:
```swift
import RTree
struct Point2D: PointN {
typealias Scalar = Double
var x: Scalar
var y: Scalar
init(x: Scalar, y: Scalar) {
self.x = x
self.y = y
}
func dimensions() -> Int {
2
}
static func from(value: Double) -> Self {
Point2D(x: value, y: value)
}
subscript(index: Int) -> Scalar {
get {
if index == 0 {
return self.x
} else {
return self.y
}
}
set(newValue) {
if index == 0 {
self.x = newValue
} else {
self.y = newValue
}
}
}
}
extension Point2D: Equatable {
static func == (lhs: Point2D, rhs: Point2D) -> Bool {
lhs.x == rhs.x && lhs.y == rhs.y
}
}
```
SpatialObject:
```swift
struct Element: SpatialObject {
typealias Point = Point2D
let point: Point
let hello = "world"
func minimumBoundingRectangle() -> BoundingRectangle {
BoundingRectangle(lower: self.point, upper: self.point)
}
func distanceSquared(point: Point2D) -> Double {
pow(point.x - self.point.x, 2) + pow(point.y - self.point.y, 2)
}
}
extension Element: Equatable {
static func == (lhs: Element, rhs: Element) -> Bool {
lhs.point == rhs.point && lhs.hello == rhs.hello
}
}
```
Then, I'm able to create an R\*-Tree that stores `Elements` over `Point2D`:
```swift
var tree = try RTree(path: path)
let zerozero = Element(point: Point2D(x: 0, y: 0))
let oneone = Element(point: Point2D(x: 1, y: 1))
let threethree = Element(point: Point2D(x: 3, y: 3))
try tree.insert(oneone)
try tree.insert(threethree)
tree.nearestNeighbor(zerozero.point)! == oneone
```
## Dependencies
None
## Contact
Feel free to email questions and comments to [emma@emma.sh](mailto:emma@emma.sh).
## Acknowledgements
- [Spade](https://crates.io/crates/spade)'s developers and contributors for making a very simple to understand R-Tree implementation that is also (Rust's equivalent to) `Codable`.
## License
RTree is released under the MIT license. [See LICENSE](https://github.com/emma-k-alexandra/RTree/blob/master/LICENSE) for details.