Switch return type to be tuple

src/methods/centroid.jl

@@ -109,7 +109,7 @@ function centroid_and_length(
     ::Union{GI.LineStringTrait, GI.LinearRingTrait},
     geom,
 )
-    T = Float64
+    T = typeof(GI.x(GI.getpoint(geom, 1)))
     # Initialize starting values
     xcentroid = T(0)
     ycentroid = T(0)
@@ -133,7 +133,7 @@ function centroid_and_length(
     end
     xcentroid /= length
     ycentroid /= length
-    return GI.Point(xcentroid, ycentroid), length
+    return (xcentroid, ycentroid), length
 end
 
 """
@@ -149,7 +149,7 @@ function centroid_and_area(
     ::Union{GI.LineStringTrait, GI.LinearRingTrait},
     geom,
 )
-    T = Float64
+    T = typeof(GI.x(GI.getpoint(geom, 1)))
     # Check that the geometry is closed
     @assert(
         GI.getpoint(geom, 1) == GI.getpoint(geom, GI.ngeom(geom)),
@@ -175,7 +175,7 @@ function centroid_and_area(
     area /= 2
     xcentroid /= 6area
     ycentroid /= 6area
-    return GI.Point(xcentroid, ycentroid), abs(area)
+    return (xcentroid, ycentroid), abs(area)
 end
 
 """
@@ -184,30 +184,24 @@ end
 Returns the centroid and area of a given polygon.
 """
 function centroid_and_area(::GI.PolygonTrait, geom)
-    T = Float64
-    # Initialize starting values
-    xcentroid = T(0)
-    ycentroid = T(0)
-    area = T(0)
-    # Exterior polygon centroid and area
-    ext_centroid, ext_area = centroid_and_area(GI.getexterior(geom))
-    area += ext_area
+    # Exterior ring's centroid and area
+    (xcentroid, ycentroid), area = centroid_and_area(GI.getexterior(geom))
     # Weight exterior centroid by area
-    xcentroid += GI.x(ext_centroid) * ext_area
-    ycentroid += GI.y(ext_centroid) * ext_area
+    xcentroid *= area
+    ycentroid *= area
     # Loop over any holes within the polygon
     for hole in GI.gethole(geom)
         # Hole polygon's centroid and area
-        interior_centroid, interior_area = centroid_and_area(hole)
+        (xinterior, yinterior), interior_area = centroid_and_area(hole)
         # Accumulate the area component into `area`
         area -= interior_area
         # Weighted average of centroid components
-        xcentroid -= GI.x(interior_centroid) * interior_area
-        ycentroid -= GI.y(interior_centroid) * interior_area
+        xcentroid -= xinterior * interior_area
+        ycentroid -= yinterior * interior_area
     end
     xcentroid /= area
     ycentroid /= area
-    return GI.Point(xcentroid, ycentroid), area
+    return (xcentroid, ycentroid), area
 end
 
 """
@@ -216,22 +210,22 @@ end
 Returns the centroid and area of a given multipolygon.
 """
 function centroid_and_area(::GI.MultiPolygonTrait, geom)
-    T = Float64
-    # Initialize starting values
-    xcentroid = T(0)
-    ycentroid = T(0)
-    area = T(0)
+    # First polygon's centroid and area
+    (xcentroid, ycentroid), area = centroid_and_area(GI.getpolygon(geom, 1))
+    # Weight first polygon's centroid by area
+    xcentroid *= area
+    ycentroid *= area
     # Loop over any polygons within the multipolygon
-    for poly in GI.getpolygon(geom)
+    for i in 2:GI.ngeom(geom) #poly in GI.getpolygon(geom)
         # Polygon centroid and area
-        poly_centroid, poly_area = centroid_and_area(poly)
+        (xpoly, ypoly), poly_area = centroid_and_area(GI.getpolygon(geom, i))
         # Accumulate the area component into `area`
         area += poly_area
         # Weighted average of centroid components
-        xcentroid += GI.x(poly_centroid) * poly_area
-        ycentroid += GI.y(poly_centroid) * poly_area
+        xcentroid += xpoly * poly_area
+        ycentroid += ypoly * poly_area
     end
     xcentroid /= area
     ycentroid /= area
-    return GI.Point(xcentroid, ycentroid), area
+    return (xcentroid, ycentroid), area
 end

test/methods/centroid.jl

@@ -3,16 +3,16 @@
     l1 = LG.LineString([[0.0, 0.0], [10.0, 0.0], [10.0, 10.0]])
     c1, len1 = GO.centroid_and_length(l1)
     c1_from_LG = LG.centroid(l1)
-    @test GI.x(c1) ≈ GI.x(c1_from_LG)
-    @test GI.y(c1) ≈ GI.y(c1_from_LG)
+    @test c1[1] ≈ GI.x(c1_from_LG)
+    @test c1[2] ≈ GI.y(c1_from_LG)
     @test len1 ≈ 20.0
 
     # Spiral line string
     l2 = LG.LineString([[0.0, 0.0], [2.5, -2.5], [-5.0, -3.0], [-4.0, 6.0], [10.0, 10.0], [12.0, -14.56]])
     c2, len2 = GO.centroid_and_length(l2)
     c2_from_LG = LG.centroid(l2)
-    @test GI.x(c2) ≈ GI.x(c2_from_LG) 
-    @test GI.y(c2) ≈ GI.y(c2_from_LG)
+    @test c2[1] ≈ GI.x(c2_from_LG) 
+    @test c2[2] ≈ GI.y(c2_from_LG)
     @test len2 ≈ 59.3090856788928
 
     # Test that non-closed line strings throw an error for centroid_and_area
@@ -22,15 +22,15 @@
     r1 = LG.LinearRing([[0.0, 0.0], [3456.0, 7894.0], [6291.0, 1954.0], [0.0, 0.0]])
     c3 = GO.centroid(r1)
     c3_from_LG = LG.centroid(r1)
-    @test GI.x(c3) ≈ GI.x(c3_from_LG) 
-    @test GI.y(c3) ≈ GI.y(c3_from_LG)
-
+    @test c3[1] ≈ GI.x(c3_from_LG) 
+    @test c3[2] ≈ GI.y(c3_from_LG)
 end
 
 @testset "Polygons" begin
     # Basic rectangle
     p1 = AG.fromWKT("POLYGON((0 0, 10 0, 10 10, 0 10, 0 0))")
     c1 = GO.centroid(p1)
+    c1 .≈ (5, 5)
     @test GI.x(c1) ≈ 5
     @test GI.y(c1) ≈ 5
 
@@ -41,8 +41,8 @@ end
     ]])
     c2, area2 = GO.centroid_and_area(p2)
     c2_from_LG = LG.centroid(p2)
-    @test GI.x(c2) ≈ GI.x(c2_from_LG)
-    @test GI.y(c2) ≈ GI.y(c2_from_LG)
+    @test c2[1] ≈ GI.x(c2_from_LG)
+    @test c2[2] ≈ GI.y(c2_from_LG)
     @test area2 ≈ LG.area(p2)
 
     # Randomly generated polygon with lots of sides
@@ -55,8 +55,8 @@ end
     ]])
     c3, area3 = GO.centroid_and_area(p3)
     c3_from_LG = LG.centroid(p3)
-    @test GI.x(c3) ≈ GI.x(c3_from_LG)
-    @test GI.y(c3) ≈ GI.y(c3_from_LG)
+    @test c3[1] ≈ GI.x(c3_from_LG)
+    @test c3[2] ≈ GI.y(c3_from_LG)
     @test area3 ≈ LG.area(p3)
 
     # Polygon with one hole
@@ -66,8 +66,8 @@ end
     ])
     c4, area4 = GO.centroid_and_area(p4)
     c4_from_LG = LG.centroid(p4)
-    @test GI.x(c4) ≈ GI.x(c4_from_LG)
-    @test GI.y(c4) ≈ GI.y(c4_from_LG)
+    @test c4[1] ≈ GI.x(c4_from_LG)
+    @test c4[2] ≈ GI.y(c4_from_LG)
     @test area4 ≈ LG.area(p4)
 
     # Polygon with two holes
@@ -78,8 +78,8 @@ end
     ])
     c5 = GO.centroid(p5)
     c5_from_LG = LG.centroid(p5)
-    @test GI.x(c5) ≈ GI.x(c5_from_LG)
-    @test GI.y(c5) ≈ GI.y(c5_from_LG)
+    @test c5[1] ≈ GI.x(c5_from_LG)
+    @test c5[2] ≈ GI.y(c5_from_LG)
 
     # Same polygon as P5 but using a GeoInterface polygon
     p6 = GI.Polygon([
@@ -88,9 +88,7 @@ end
         [(-3.0, -9.0), (3.0, -9.0), (3.0, -8.5), (-3.0, -8.5), (-3.0, -9.0)],
     ])
     c6 = GO.centroid(p6)
-    @test GI.x(c6) ≈ GI.x(c5)
-    @test GI.y(c6) ≈ GI.y(c5)
-
+    @test all(c5 .≈ c6)
 end
 @testset "MultiPolygons" begin
     # Combine poylgons made above
@@ -106,7 +104,7 @@ end
     ])
     c1, area1 = GO.centroid_and_area(m1)
     c1_from_LG = LG.centroid(m1)
-    @test GI.x(c1) ≈ GI.x(c1_from_LG)
-    @test GI.y(c1) ≈ GI.y(c1_from_LG)
+    @test c1[1] ≈ GI.x(c1_from_LG)
+    @test c1[2] ≈ GI.y(c1_from_LG)
     @test area1 ≈ LG.area(m1)
 end