forward metadata methods for RasterDataset (#186)

Author: visr

src/raster/array.jl

@@ -40,10 +40,16 @@ end
 # for raster-like datasets.
 for f in (:getgeotransform, :nraster, :getband, :getproj,
     :width, :height, :destroy, :getdriver, :filelist, :listcapability, 
-    :ngcp, :copy, :write, :testcapability, :setproj!, :buildoverviews!)
+    :ngcp, :copy, :write, :testcapability, :setproj!, :buildoverviews!,
+    :metadata, :metadatadomainlist)
     eval(:($(f)(x::RasterDataset, args...; kwargs...) = $(f)(x.ds, args...; kwargs...)))
 end
 
+# Here we need to special-case, to avoid a method ambiguity
+function metadataitem(obj::RasterDataset, name::AbstractString; kwargs...)
+    return metadataitem(obj.ds, name; kwargs...)
+end
+
 # Here we need to special-case, because source and dest might be rasters
 copywholeraster(x::RasterDataset,y::AbstractDataset;kwargs...) = copywholeraster(x.ds,y;kwargs...)
 copywholeraster(x::RasterDataset,y::RasterDataset;kwargs...) = copywholeraster(x.ds,y.ds;kwargs...)

test/test_gdal_tutorials.jl

@@ -48,6 +48,7 @@ import ArchGDAL; const AG = ArchGDAL
 
         @test AG.metadatadomainlist(dataset) == ["IMAGE_STRUCTURE", "", "DERIVED_SUBDATASETS"]
         @test AG.metadata(dataset) == ["AREA_OR_POINT=Area"]
+        @test AG.metadataitem(dataset, "AREA_OR_POINT") == "Area"
         @test AG.metadata(dataset, domain = "IMAGE_STRUCTURE") == ["INTERLEAVE=BAND"]
         @test AG.metadata(dataset, domain = "") == ["AREA_OR_POINT=Area"]
         @test AG.metadata(dataset, domain = "DERIVED_SUBDATASETS") == [
@@ -56,6 +57,14 @@ import ArchGDAL; const AG = ArchGDAL
         ]
     end
 
+    # Get metadata from a RasterDataset
+    AG.readraster("data/utmsmall.tif") do dataset
+        # interestingly the list order below is different from the order above
+        @test AG.metadatadomainlist(dataset) == ["IMAGE_STRUCTURE", "DERIVED_SUBDATASETS", ""]
+        @test AG.metadata(dataset) == ["AREA_OR_POINT=Area"]
+        @test AG.metadataitem(dataset, "AREA_OR_POINT") == "Area"
+    end
+
     # Techniques for Creating Files
     @test GDAL.gdalgetmetadataitem(driver.ptr, "DCAP_CREATE", "") == "YES"
     @test GDAL.gdalgetmetadataitem(driver.ptr, "DCAP_CREATECOPY", "") == "YES"