Add function to calculate bounding box (#149)

* add bounding box function

* add test for bounding box

src/ogr/geometry.jl

@@ -214,6 +214,18 @@ function envelope3d(geom::AbstractGeometry)
     return envelope[]
 end
 
+"""
+    boundingbox(geom::AbstractGeometry)
+
+Returns a bounding box polygon (CW) built from envelope coordinates
+"""
+function boundingbox(geom::AbstractGeometry)
+    coordinates = envelope(geom)
+    MinX, MaxX, MinY, MaxY = coordinates.MinX, coordinates.MaxX, coordinates.MinY, coordinates.MaxY
+    # creates a CW closed ring polygon
+    return createpolygon([[MaxY, MinX], [MaxY, MaxX], [MinY, MaxX], [MinY, MinX], [MaxY, MinX]])
+end
+
 """
     toWKB(geom::AbstractGeometry, order::OGRwkbByteOrder = GDAL.wkbNDR)
 

test/test_cookbook_geometry.jl

@@ -666,6 +666,15 @@ end
     end
 end
 
+@testset "Calculate Bounding Box of a Geometry" begin
+    wkt = "POLYGON ((1162440.5712740074 672081.4332727483, 1162440.5712740074 647105.5431482664, 1195279.2416228633 647105.5431482664, 1195279.2416228633 672081.4332727483, 1162440.5712740074 672081.4332727483))"
+    expected = AG.createpolygon([[672081.4332727483, 1162440.5712740074], [672081.4332727483, 1195279.2416228633], [647105.5431482664, 1195279.2416228633], [647105.5431482664, 1162440.5712740074], [672081.4332727483, 1162440.5712740074]])
+    AG.fromWKT(wkt) do polygon
+        calculated = AG.boundingbox(polygon)
+        @test AG.equals(expected, calculated)
+    end
+end
+
 @testset "Calculate the Area of a Geometry" begin
     wkt = "POLYGON ((1162440.5712740074 672081.4332727483, 1162440.5712740074 647105.5431482664, 1195279.2416228633 647105.5431482664, 1195279.2416228633 672081.4332727483, 1162440.5712740074 672081.4332727483))"
     AG.fromWKT(wkt) do poly