Merge #459

459: More Area implementations. r=frewsxcv a=frewsxcv

- `impl<T> Area<T> for Point<T>`
- `impl<T> Area<T> for LineString<T>`
- `impl<T> Area<T> for MultiPoint<T>`
- `impl<T> Area<T> for MultiLineString<T>`
- `impl<T> Area<T> for Geometry<T>`
- `impl<T> Area<T> for GeometryCollection<T>`

Co-authored-by: Corey Farwell <coreyf@rwell.org>

Author: bors[bot]

geo/src/algorithm/area.rs

@@ -1,4 +1,7 @@
-use crate::{CoordinateType, Line, LineString, MultiPolygon, Polygon, Rect, Triangle};
+use crate::{
+    CoordinateType, Geometry, GeometryCollection, Line, LineString, MultiLineString, MultiPoint,
+    MultiPolygon, Point, Polygon, Rect, Triangle,
+};
 use num_traits::Float;
 
 use crate::algorithm::winding_order::twice_signed_ring_area;
@@ -42,6 +45,24 @@ where
     twice_signed_ring_area(linestring) / (T::one() + T::one())
 }
 
+impl<T> Area<T> for Point<T>
+where
+    T: CoordinateType,
+{
+    fn area(&self) -> T {
+        T::zero()
+    }
+}
+
+impl<T> Area<T> for LineString<T>
+where
+    T: CoordinateType,
+{
+    fn area(&self) -> T {
+        T::zero()
+    }
+}
+
 impl<T> Area<T> for Line<T>
 where
     T: CoordinateType,
@@ -64,6 +85,24 @@ where
     }
 }
 
+impl<T> Area<T> for MultiPoint<T>
+where
+    T: CoordinateType,
+{
+    fn area(&self) -> T {
+        T::zero()
+    }
+}
+
+impl<T> Area<T> for MultiLineString<T>
+where
+    T: CoordinateType,
+{
+    fn area(&self) -> T {
+        T::zero()
+    }
+}
+
 impl<T> Area<T> for MultiPolygon<T>
 where
     T: Float,
@@ -96,6 +135,38 @@ where
     }
 }
 
+impl<T> Area<T> for Geometry<T>
+where
+    T: Float,
+{
+    fn area(&self) -> T {
+        match self {
+            Geometry::Point(g) => g.area(),
+            Geometry::Line(g) => g.area(),
+            Geometry::LineString(g) => g.area(),
+            Geometry::Polygon(g) => g.area(),
+            Geometry::MultiPoint(g) => g.area(),
+            Geometry::MultiLineString(g) => g.area(),
+            Geometry::MultiPolygon(g) => g.area(),
+            Geometry::GeometryCollection(g) => g.area(),
+            Geometry::Rect(g) => g.area(),
+            Geometry::Triangle(g) => g.area(),
+        }
+    }
+}
+
+impl<T> Area<T> for GeometryCollection<T>
+where
+    T: Float,
+{
+    fn area(&self) -> T {
+        self.0
+            .iter()
+            .map(|g| g.area())
+            .fold(T::zero(), |acc, next| acc + next)
+    }
+}
+
 #[cfg(test)]
 mod test {
     use crate::algorithm::area::Area;