✨ ASCII (Fixes #26)

docs/src/man/data.md

@@ -21,3 +21,9 @@ bioclim
 ```@docs
 landcover
 ```
+
+## ASCII files
+
+```@docs
+ascii
+```

src/datasets/ascii.jl

@@ -0,0 +1,69 @@
+function _get_asc_field(lines, field, type)
+    field_line = first(filter(startswith(field), lines))
+    return parse(type, last(split(field_line, " "))), findfirst(startswith(field), lines)
+end
+
+"""
+    ascii(file::AbstractString, datatype::Type{T}=Float64) where {T <: Number}
+
+Reads the content of a grid file to a `SimpleSDMPredictor`, the type of which is
+given by the `datatype` argument.
+"""
+function ascii(file::AbstractString, datatype::Type{T}=Float64) where {T <: Number}
+    lines = lowercase.(readlines(file))
+    # Get the information
+    ncols, ncols_line = _get_asc_field(lines, "ncols", Int64)
+    nrows, nrows_line = _get_asc_field(lines, "nrows", Int64)
+    xl, xl_line = _get_asc_field(lines, "xllcorner", Float64)
+    yl, yl_line = _get_asc_field(lines, "yllcorner", Float64)
+    cs, cs_line = _get_asc_field(lines, "cellsize", Float64)
+    nodata, nodata_line = _get_asc_field(lines, "nodata", datatype)
+    # Read the data
+    M = zeros(datatype, (ncols, nrows))
+    data_start = nodata_line+1
+    data_end = length(lines)
+    for line_id in data_start:data_end
+        M[:,nrows-(line_id-(data_start))] = parse.(datatype, split(lines[line_id]))
+    end
+    println(permutedims(M))
+    # Put data in the grid
+    grid = convert(Matrix{Union{datatype,Nothing}}, permutedims(M))
+    for i in eachindex(M)
+        if grid[i] == nodata
+            grid[i] = nothing
+        end
+    end
+    @info ncols, nrows, cs
+    return SimpleSDMPredictor(grid, xl, xl+cs*2ncols, yl, yl+cs*2nrows)
+end
+
+"""
+    ascii(layer::SimpleSDMPredictor{T}, file::AbstractString; nodata::T=convert(T, -9999)) where {T <: Number}
+
+Writes a `layer` to a grid file, with a given `nodata` value. The layer must store numbers.
+"""
+function ascii(layer::SimpleSDMPredictor{T}, file::AbstractString; nodata::T=convert(T, -9999)) where {T <: Number}
+    if !(stride(layer)[1] ≈ stride(layer)[2])
+        throw(DimensionMismatch("The cells of the layer to write must be square (i.e. both values of stride must be equal)"))
+    end
+    open(file, "w") do io 
+
+        write(io, "ncols $(size(layer, 2))\n")
+        write(io, "nrows $(size(layer, 1))\n")
+        write(io, "cellsize $(stride(layer)[1])\n")
+        write(io, "xllcorner $(layer.left)\n")
+        write(io, "yllcorner $(layer.bottom)\n")
+        write(io, "yllcorner $(layer.bottom)\n")
+        write(io, "nodata_value $(nodata)\n")
+        for row in reverse(1:size(layer.grid, 1))
+            for el in layer.grid[row,:]
+                if isnothing(el)
+                    write(io, "$(nodata) ")
+                else
+                    write(io, "$(el) ")
+                end
+            end
+            write(io, "\n")
+        end
+    end
+end

test/ascii.jl

@@ -0,0 +1,24 @@
+module SSLTestASCII
+using SimpleSDMLayers
+using Test
+
+M = rand(Float64, 4, 8)
+M = convert(Matrix{Union{Nothing,Float64}}, M)
+M[rand(Bool, size(M))] .= nothing
+S = SimpleSDMPredictor(M, 0.0, 2.0, 0.0, 1.0)
+
+ascii(S, "test.asc")
+U = ascii("test.asc")
+
+@test isfile("test.asc")
+@test all(S.grid .== U.grid)
+@test S.left == U.left
+@test S.bottom == U.bottom
+@test S.right == U.right
+@test S.top == U.top
+@test s
+@test size(S) == size(U)
+
+rm("test.asc")
+
+end

test/runtests.jl

@@ -9,6 +9,7 @@ tests = [
    "overloads" => "overloads.jl",
    "generated" => "generated.jl",
    "import" => "dataread.jl",
+   "ascii" => "ascii.jl",
    "worldclim" => "worldclim.jl",
    "landcover" => "landcover.jl",
    "chelsa" => "chelsa.jl",