Update comments and cleanup tests

src/transformations/simplify.jl

@@ -215,7 +215,7 @@ Note: user input `tol` is squared to avoid uneccesary computation in algorithm.
 end
 
 #= Simplify using the DouglasPeucker algorithm - nice gif of process on wikipedia:
-(https://en.wikipedia.org/wiki/Ramer-Douglas-Peucker_algorithm) =#
+(https://en.wikipedia.org/wiki/Ramer-Douglas-Peucker_algorithm). =#
 function _simplify(alg::DouglasPeucker, points::Vector, preserve_endpoint)
     npoints = length(points)
     npoints <= MIN_POINTS && return points
@@ -306,7 +306,8 @@ function _simplify(alg::DouglasPeucker, points::Vector, preserve_endpoint)
 end
 
 #= find maximum distance of any point between the start_idx and end_idx to the line formed
-by conencting the points at start_idx and end_idx. =#
+by conencting the points at start_idx and end_idx. Note that the first index of maximum
+value will be used, which might cause differences in results from other algorithms.=#
 function _find_max_squared_dist(points, start_idx, end_idx)
     max_idx = 0
     max_dist = zero(Float64)

test/transformations/simplify.jl

@@ -1,11 +1,8 @@
-using Test
-# import GeoInterface as GI
-# import GeometryOps as GO
 import GeoJSON
 import JLD2
 
-@testset "simplify" begin
-    datadir = realpath(joinpath(dirname(pathof(GO)), "../test/data"))
+datadir = realpath(joinpath(dirname(pathof(GO)), "../test/data"))
+@testset "RadialDistance and VisvalingamWhyatt" begin
     fc = GeoJSON.read(joinpath(datadir, "simplify.geojson"))
     fc2 = GeoJSON.read(joinpath(datadir, "simplify2.geojson"))
     fcs = [fc for i in 1:100]
@@ -16,7 +13,8 @@ import JLD2
         GO.simplify(T(tol=0.001), fc; threaded=true, calc_extent=true)
         GO.simplify(T(tol=0.001), fcs; threaded=true, calc_extent=true)
     end
-
+end
+@testset "DouglasPeucker" begin
     poly_coords = JLD2.jldopen(joinpath(datadir, "complex_polygons.jld2"))["verts"][1:4]
     for c in poly_coords
         npoints = length(c[1])