Module: NSWTopo::Raster

Included in:
ArcGISRaster, ColourMask, Import, Relief, Vegetation
Defined in:
lib/nswtopo/layer/raster.rb

Instance Method Summary collapse

Instance Method Details

#create ⇒ Object 



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# File 'lib/nswtopo/layer/raster.rb', line 3

def create
  Dir.mktmppath do |temp_dir|
    args = ["-t_srs", @map.projection, "-r", "bilinear", "-cutline", "GeoJSON:/vsistdin/", "-te", *@map.te, "-of", "GTiff", "-co", "TILED=YES"]
    args += ["-tr", @mm_per_px, @mm_per_px] if Numeric === @mm_per_px
    OS.gdalwarp *args, get_raster(temp_dir), "/vsistdout/" do |stdin|
      stdin.puts @map.cutline.to_json
    end.then do |tif|
      @map.write filename, tif
    end
  end
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/nswtopo/layer/raster.rb', line 19

def empty?
  false
end

#filename ⇒ Object 



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# File 'lib/nswtopo/layer/raster.rb', line 15

def filename
  "#{@name}.tif"
end

#image_element ⇒ Object 



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# File 'lib/nswtopo/layer/raster.rb', line 23

def image_element
  REXML::Element.new("image").tap do |image|
    tif = @map.read filename
    OS.gdalinfo "-json", "/vsistdin/" do |stdin|
      stdin.binmode.write tif
    end.then do |json|
      JSON.parse(json).values_at "size", "geoTransform"
    end.then do |(width, height), (_, mm_per_px, *)|
      image.add_attributes "width" => width, "height" => height, "transform" => "scale(#{mm_per_px})"
    end
    OS.gdal_translate "-of", "PNG", "-co", "ZLEVEL=9", "/vsistdin/", "/vsistdout/" do |stdin|
      stdin.binmode.write tif
    end.then do |png|
      image.add_attributes "href" => "data:image/png;base64,#{Base64.encode64 png}", "image-rendering" => "optimizeQuality"
    end
  end
end

#to_s ⇒ Object 



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# File 'lib/nswtopo/layer/raster.rb', line 41

def to_s
  OS.gdalinfo "-json", "/vsistdin/" do |stdin|
    stdin.binmode.write @map.read(filename)
  end.then do |json|
    JSON.parse(json).values_at "size", "geoTransform"
  end.then do |(width, height), (_, mm_per_px, *)|
    resolution, ppi = @map.to_metres(mm_per_px), 25.4 / mm_per_px
    megapixels = width * height / 1024.0 / 1024.0
    "%s: %i×%i (%.1fMpx) @ %.3gm/px (%.3g ppi)" % [@name, width, height, megapixels, resolution, ppi]
  end
end