Test zonal on geometries with extents that go beyond the raster (#817)

* test geometries with extents that go beyond the raster

* Reverse didn't solve anything, remove it

* fix bug

* fix alg

* fix test

---------

Co-authored-by: Rafael Schouten <[email protected]>

Author: asinghvi17

src/methods/burning/edges.jl

@@ -42,6 +42,7 @@ _x_at_y(e::Edge, y) = (y - e.start[2]) * e.gradient + e.start[1]
 struct Edges <: AbstractVector{Edge}
     edges::Vector{Edge}
     max_ylen::Int
+    min_y::Int
     edge_count::Int
 end
 Edges(geom, dims; kw...) = Edges(GI.geomtrait(geom), geom, dims; kw...)
@@ -55,12 +56,14 @@ function Edges(
     # TODO fix bug that requires this to be redefined
     edges = Vector{Edge}(undef, 0)
     local edge_count = max_ylen = 0
+    local min_y = typemax(Int)
     if tr isa GI.AbstractCurveTrait
-        edge_count, max_ylen = _to_edges!(edges, geom, dims, edge_count)
+        edge_count, max_ylen, min_y = _to_edges!(edges, geom, dims, edge_count)
     else
         for ring in GI.getring(geom)
-             edge_count, ring_max_ylen = _to_edges!(edges, ring, dims, edge_count)
+             edge_count, ring_max_ylen, ring_min_y = _to_edges!(edges, ring, dims, edge_count)
              max_ylen = max(max_ylen, ring_max_ylen)
+             min_y = min(min_y, ring_min_y)
         end
     end
 
@@ -72,7 +75,7 @@ function Edges(
         sort!(edges1; scratch)
     end
 
-    return Edges(edges, max_ylen, edge_count)
+    return Edges(edges, max_ylen, min_y, edge_count)
 end
 
 Base.parent(edges::Edges) = edges.edges
@@ -99,8 +102,9 @@ end
     local firstpos = prevpos = nextpos = Position((0.0, 0.0), 0)
     isfirst = true
     local max_ylen = 0
+    local min_y = typemax(Int)
 
-    GI.npoint(geom) > 0 || return edge_count, max_ylen
+    GI.npoint(geom) > 0 || return edge_count, max_ylen, min_y
     xlookup, ylookup = lookup(dims, (X(), Y())) 
     (length(xlookup) > 0 && length(ylookup) > 0) || return edge_count, max_ylen
 
@@ -136,6 +140,7 @@ end
         edge = Edge(prevpos, nextpos)
         _add_edge!(edges, edge, edge_count)
         max_ylen = max(max_ylen, edge.iystop - edge.iystart)
+        min_y = min(min_y, edge.iystart)
         prevpos = nextpos
         prevpoint = p
     end
@@ -145,11 +150,12 @@ end
         edge = Edge(prevpos, firstpos)
         # Update the longest y distance of any edge
         max_ylen = max(max_ylen, edge.iystop - edge.iystart)
+        min_y = min(min_y, edge.iystart)
         # assign/push the edge to edges
         _add_edge!(edges, edge, edge_count)
     end
 
-    return edge_count, max_ylen
+    return edge_count, max_ylen, min_y
 end
 
 function _add_edge!(edges, edge, edge_count)

src/methods/burning/polygon.jl

@@ -67,11 +67,11 @@ function _set_crossings!(crossings::Vector{Float64}, edges::Edges, iy::Int, prev
     # max_ylen tells us how big the largest y edge is.
     # We can use this to jump back from the last y position
     # rather than iterating from the start of the edges
-    ypos = max(1, prev_ypos - edges.max_ylen - 1)
-    ncrossings = 0
-    # We know the maximum size on y, so we can start from ypos 
+    ypos = max(edges.min_y, prev_ypos - edges.max_ylen - 1)
     start_ypos = searchsortedfirst(edges, ypos)
+    # We know the maximum size on y, so we can start from ypos 
     prev_ypos = start_ypos
+    ncrossings = 0
     for i in start_ypos:lastindex(edges)
         e = @inbounds edges[i]
         # Edges are sorted on y, so we can skip

test/methods.jl

@@ -220,6 +220,12 @@ end
             @test sum(skipmissing(mask(polytemplate; with=polygon, boundary=:touches, invert=true))) == prod(size(polytemplate)) - 21 * 21
         end
     end
+
+    @testset "geometry encompassing raster" begin
+        geom = GeoInterface.Polygon([GeoInterface.LinearRing([(0.0, 0.0), (0.0, 10.0), (10.0, 10.0), (10.0, 0.0), (0.0, 0.0)])])
+        raster = Raster(ones(X(1:0.1:2), Y(1:0.1:2)), missingval=false)
+        @test sum(mask(raster; with=geom)) == sum(raster)
+    end
 end
 
 @testset "mask_replace_missing" begin
@@ -755,4 +761,4 @@ test = rebuild(ga; name = :test)
 
     @test_throws "strictly positive" Rasters.sample(StableRNG(123), test, 3, skipmissing = true, replace = false)
     @test_throws "Cannot draw" Rasters.sample(StableRNG(123), test, 5, replace = false)
-end
+end