fix error with undefined similar in polygonize (#202)

* call length on AbstractRange

* explicitly set length of xbounds and ybounds

* add some tests

* use range with explicit step for bounds

src/methods/polygonize.jl

@@ -117,12 +117,12 @@ function _polygonize(f::Base.Callable, xs::AbstractRange, ys::AbstractRange, A::
     xhalf = step(xs) / 2
     yhalf = step(ys) / 2
     # Make bounds ranges first to avoid floating point error making gaps or overlaps
-    xbounds = first(xs) - xhalf : step(xs) : last(xs) + xhalf
-    ybounds = first(ys) - yhalf : step(ys) : last(ys) + yhalf
+    xbounds = range(first(xs) - xhalf; step = step(xs), length = length(xs) + 1)
+    ybounds = range(first(ys) - yhalf; step = step(ys), length = length(ys) + 1)
     Tx = eltype(xbounds)
     Ty = eltype(ybounds)
-    xvec = similar(Vector{Tuple{Tx,Tx}}, xs)
-    yvec = similar(Vector{Tuple{Ty,Ty}}, ys)
+    xvec = similar(Vector{Tuple{Tx,Tx}}, length(xs))
+    yvec = similar(Vector{Tuple{Ty,Ty}}, length(ys))
     for (xind, i) in enumerate(eachindex(xvec))
         xvec[i] = xbounds[xind], xbounds[xind+1]
     end

test/methods/polygonize.jl

@@ -1,7 +1,32 @@
 using GeometryOps, GeoInterface, Test
-import OffsetArrays, DimensionalData, Rasters
 using ..TestHelpers
 
+import GeometryOps as GO 
+import GeoInterface as GI
+
+@testset "Polygonize with xs and ys, without offsetarrays" begin
+    @test !(@isdefined OffsetArrays) # to make sure this isn't loaded somewhere else
+    data  = rand(1:4, 100, 100) .== 1
+    unitrange = 1:100
+    steprange = 1:1:100
+    steprangelen = range(1, 100; length = 100)
+    data_mp = polygonize(data)
+    for range in (unitrange, steprange, steprangelen)
+        data_mp_range = polygonize(range, range, data)
+        @test GO.equals(data_mp, data_mp_range)
+    end
+    # ideally we'd have a better test to make sure this returns what we think it does
+    data_mp_range200 = polygonize(2:2:200, 2:2:200, data)
+    @test length(GI.coordinates(data_mp_range200)) == length(GI.coordinates(data_mp))
+
+    # this is an example that could throw floating point error
+    range_floats = -1.333333333333343:0.041666666666666664:0.374999999999986
+    data2 = rand(1:4, length(range_floats), length(range_floats)) .== 1
+    data_mp_range_floats = polygonize(range_floats, range_floats, data2)
+end
+
+import OffsetArrays, DimensionalData, Rasters
+
 # Missing holes throw a warning, so testing there are
 # no warnings in a range of randomisation is one way to test 
 # that things are working, without testing explicit return values
@@ -68,3 +93,15 @@ end
         @test GI.crs(evil_mp) == GI.crs(evil)
     end
 end
+
+@testset "Polygonize with xs and ys, with offsetarrays" begin
+    data  = rand(1:4, 100, 100) .== 1
+    unitrange = 1:100
+    steprange = 1:1:100
+    steprangelen = range(1, 100; length = 100)
+    data_mp = polygonize(data)
+    for range in (unitrange, steprange, steprangelen)
+        data_mp_range = polygonize(range, range, data)
+        @test GO.equals(data_mp, data_mp_range)
+    end
+end