# rsgeo

rsgeo is a geography tool which is written with Rust. 

## Installation

Add it to your Cargo.toml

```
[dependencies]
rsgeo = "0.1.3"
```

## Usage

Create two points with latitude and longitude,and get distance between two points

```rust
use rsgeo::prelude::*;
let p1 = Point::new(30.12, 125.26).unwrap(); 
let p2 = Point::new(32.54, 107.15).unwrap();
println!("{}",p1.distance(&p2)); //1740784.4 
```

Get the degree from p1 to p2(the degree to north)

```rust
println!("{}",p1.degree(&p2)); //-82.38877
```

Create a Location

```rust
let p = Point::new(35.12,46.15).unwrap();
let loc = Location::new(p,232500);
// a location is a point with a unix timestamp
```

Get the distance of location and point. 

```rust
println!("{}",loc.distance_from_point(&p1)); //7237628.5
```

Get the speed of two locations

```rust
let loc1 = Location::new(Point::new(25.12,110.15).unwrap(),100);
let loc2 = Location::new(Point::new(25.119,109.995).unwrap(),3700);
assert!(loc1.speed(&loc2) - 4.3396673 < 1e-6); // m/s
```

Create Area and test if the point is in it.

```rust
let ra = RecArea::new(35.0, 36.0, 110.0, 115.0).unwrap();
let pa = Point::new(32.0,112.0).unwrap();
let pb = Point::new(35.1,112.0).unwrap();
assert!(!ra.contains(&pa));
assert!(ra.contains(&pb));
let ca = CircleArea::new(Point::new(35.0, 110.0).unwrap(), 350_000.0);
let pa = Point::new(32.0, 112.0).unwrap();
let pb = Point::new(35.1, 112.0).unwrap();
assert!(!ca.contains(&pa));
assert!(ca.contains(&pb));
```

Create a polygon and test if the point is in it.

```rust
let pa = Point::new(32.0,112.0).unwrap();
let pb = Point::new(35.1,112.0).unwrap();
let pc = Point::new(35.3,112.5).unwrap();
let pg = Polygon::new(vec![pa,pb,pc]);
assert!(pg.is_err());
// polygon must have more than 3 points.The first point must be the same with the last point.
// the polygon can be convex or concave whatever
let pg = Polygon::new(vec![pa,pb,pc,pa]);
assert_eq!(pg.unwrap().len(),4);
let pt1 =  Point::new(35.0,112.2).unwrap();
let pt2 =  Point::new(34.29,110.3).unwrap();
assert!(pg.contains(&pt1));
assert!(!pg.contains(&pt2));
```

Create a Trajectory

```rust
// A trajectory is a vector of some locations which must be chronological order.
let mut t = Trajectory::new();
let mut t = Trajectory::with_capacity(); // like a vector
let loc1 = Location::new(Point::new(25.11,120.98).unwrap(),0);
let loc2 = Location::new(Point::new(26.2,121.1).unwrap(),7200);
let loc3 = Location::new(Point::new(26.3,121.3).unwrap(),14400);
t.push_location(&loc1);
t.push_location(&loc2);
t.push_location(&loc3);
let mut t = Trajectory::from(vec![loc1,loc2,loc3].as_slice()).unwrap(); // or initialize with a slice of locations
```

Get the num of locations in Trajectory

```rust
assert_eq!(t.len(),3);
```

Test if the trajectory passes area or polygon

```rust
let area1 = RecArea::new(25.07,27.12,119.9,125.0).unwrap();
assert!(t.pass_rec_area(&area1));
```

Get the speed of a trajectory

```rust
let loc1 = Location::new(Point::new(25.11,120.98).unwrap(),0);
let loc2 = Location::new(Point::new(26.2,121.1).unwrap(),7200);
let loc3 = Location::new(Point::new(26.3,121.3).unwrap(),14400);
let mut t = Trajectory::with_capacity(3);
t.push_location(&loc1);
t.push_location(&loc2);
t.push_location(&loc3);
assert!((t.max_speed().unwrap() - 16.9352).abs() < 1e-3);
assert!((t.mean_speed().unwrap() - 10.055225).abs() < 1e-6);
```

Get the sum of distance of a trajectory

```rust
assert!((t.sum_distance() - 144795.25).abs() < 1e6);
```

Compare two trajectories and return the similarity of two trajectories.

```rust
use rsgeo::prelude::*;
use rsgeo::measure::stlc_trajectory_similarity;
assert!((stlc_trajectory_similarity(&t, &t, 0.5).unwrap()-1.0).abs() < 1e-6);
// stlc is spatiotemporal linear combin distance
// the function returns similarity which is in (0,1]
```