move to transformations

test/transformations.jl

@@ -0,0 +1,52 @@
+using Test
+
+import GeoInterface as GI
+import GeometryOps as GO
+using GeoFormatTypes
+import Proj
+
+@testset "reproject" begin
+    ring1 = GI.LinearRing([(1, 2), (7, 4), (5, 6), (1, 2)])
+    ring2 = GI.LinearRing([(11, 2), (20, 4), (15, 6), (11, 2)])
+    hole2 = GI.LinearRing([(14, 4), (16, 4), (17, 5), (14, 4)])
+
+    # Set up a regular tranformation of the points for reference
+    source_crs = convert(Proj.CRS, EPSG(4326))
+    target_crs = convert(Proj.CRS, EPSG(3857))
+    trans = Proj.Transformation(source_crs, target_crs; always_xy=true)
+
+    polygon1 = GI.Polygon([ring1])
+    polygon2 = GI.Polygon([ring2, hole2])
+    multipolygon = GI.MultiPolygon([polygon1, polygon2])
+
+    ref_points3857 = map(GI.getpoint(multipolygon)) do p
+        trans([GI.x(p), GI.y(p)])
+    end
+
+    multipolygon3857 = GO.reproject(multipolygon, EPSG(4326), EPSG(3857))
+    multipolygon4326 = GO.reproject(multipolygon3857; target_crs=EPSG(4326))
+    points4326_1 = collect(GI.getpoint(multipolygon))
+    points4326_2 = GI.getcoord.(GI.getpoint(multipolygon4326))
+    points3857 = GI.getcoord.(GI.getpoint(multipolygon3857))
+
+    # Comparison to regular `trans` on points
+    @test all(map((p1, p2) -> all(map(isapprox, p1, p2)), ref_points3857, points3857))
+
+    # Round trip comparison
+    @test all(map((p1, p2) -> all(map(isapprox, p1, p2)), points4326_1, points4326_2))
+
+    # Embedded crs check
+    @test GI.crs(multipolygon3857) == EPSG(3857)
+    @test GI.crs(multipolygon4326) == EPSG(4326)
+end
+
+
+
+@testset "flip" begin
+    geom = GI.Polygon([GI.LinearRing([(1, 2), (3, 4), (5, 6), (1, 2)]), 
+                       GI.LinearRing([(3, 4), (5, 6), (6, 7), (3, 4)])])
+
+
+    @test GO.flip(geom) == GI.Polygon([GI.LinearRing([(2, 1), (4, 3), (6, 5), (2, 1)]), 
+                                       GI.LinearRing([(4, 3), (6, 5), (7, 6), (4, 3)])])
+end