Access to RasterDataSources could give error that indicates that ArchGDAL needs to be loaded in 0.8

[felixcremer]

In Rasters 0.8 I get the following error, when I try to load a file from RasterDataSources:

julia> A = Raster(WorldClim{BioClim}, 5)
ERROR: MethodError: no method matching Raster(::Type{WorldClim{BioClim}}, ::Int64)

Closest candidates are:
  Raster(::Any, ::Tuple; name, kw...)
   @ Rasters ~/.julia/packages/Rasters/IELXJ/src/array.jl:282
  Raster(::Any, ::AbstractString)
   @ Rasters ~/.julia/packages/Rasters/IELXJ/src/array.jl:308
  Raster(::Any, ::AbstractString, ::Any; crs, mappedcrs, dims, refdims, name, metadata, missingval, source, write, lazy, dropband)
   @ Rasters ~/.julia/packages/Rasters/IELXJ/src/array.jl:308

Stacktrace:
 [1] top-level scope
   @ REPL[151]:1

This is working in 0.7.

[felixcremer]

Ok, this is only broken when I haven't loaded ArchGDAL, but it would be nice to get a error message indicating that I need to load ArchGDAL.

[rafaqz]

It should need both RasterDataSources and ArchGDAL.

But to make a better error, its not easy to get at that method using dispatch without having the supertypes avalable. Its also not clear from the signature if you need ArchGDAL or NCDatasets.

If you can work out how to do it a PR would be nice.

[rafaqz]

This is implemented now