Module: NSWTopo::Spot

Includes:
DEM, Log, Vector
Defined in:
lib/nswtopo/layer/spot.rb

Defined Under Namespace

Modules: Candidate

Constant Summary collapse

CREATE = 
%w[spacing smooth prefer]
DEFAULTS = 
YAML.load <<~YAML
  spacing: 15
  smooth: 0.2
  symbol:
    circle:
      r: 0.2
      stroke: none
      fill: black
  labels:
    font-family: Arial, Helvetica, sans-serif
    font-size: 1.4
    margin: 0.7
    position: [right, above, below, left, aboveright, belowright, aboveleft, belowleft]
YAML
NOISE_MM =

TODO: noise sensitivity should depend on contour interval

2.0

Constants included from Vector

Vector::FONT_SCALED_ATTRIBUTES, Vector::MARGIN, Vector::SVG_ATTRIBUTES

Constants included from Log

Log::FAILURE, Log::NEUTRAL, Log::SUCCESS, Log::UPDATE

Instance Method Summary collapse

Methods included from Vector

#categorise, #create, #drawing_features, #features, #filename, #labeling_features, #params_for, #render, #svg_path_data, #to_mm, #to_s

Methods included from DEM

#blur_dem, #get_dem

Methods included from GDALGlob

#gdal_raster?, #gdal_rasters

Methods included from Log

#log_abort, #log_neutral, #log_success, #log_update, #log_warn

Instance Method Details

#candidates ⇒ Object 



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# File 'lib/nswtopo/layer/spot.rb', line 75

def candidates
  @candidates ||= Dir.mktmppath do |temp_dir|
    raw_path = temp_dir / "raw.tif"
    dem_path = temp_dir / "dem.tif"
    aspect_path = temp_dir / "aspect.bil"

    if @smooth.zero?
      get_dem temp_dir, dem_path
    else
      get_dem temp_dir, raw_path
      blur_dem raw_path, dem_path
    end

    log_update "%s: calculating aspect map" % @name
    OS.gdaldem "aspect", dem_path, aspect_path, "-trigonometric"

    Enumerator.new do |yielder|
      aspect = ESRIHdr.new aspect_path, -9999
      indices = [-1, 0, 1].map do |row|
        [-1, 0, 1].map do |col|
          row * aspect.ncols + col - 1
        end
      end.flatten.values_at(0,3,6,7,8,5,2,1,0)

      aspect.nrows.times do |i|
        log_update "%s: finding flat areas: %.1f%%" % [@name, 100.0 * i / aspect.nrows]
        aspect.ncols.times do |j|
          indices.map!(&:next)
          next if i < 1 || j < 1 || i > aspect.nrows - 2 || j > aspect.ncols - 2
          ring = aspect.values.values_at *indices
          next if ring.any?(&:nil?)
          anticlockwise = ring.each_cons(2).map do |a1, a2|
            (a2 - a1) % 360 < 180
          end
          yielder << [[j + 1, i + 1], true] if anticlockwise.all?
          yielder << [[j + 1, i + 1], false] if anticlockwise.none?
        end
      end
    end.group_by(&:last).flat_map do |knoll, group|
      pixels = group.map(&:first)
      locations = raster_locations dem_path, pixels
      elevations = raster_values dem_path, pixels

      locations.zip(elevations).map do |coordinates, elevation|
        GeoJSON::Point.new coordinates, "knoll" => knoll, "elevation" => elevation
      end.each do |feature|
        feature.extend Candidate, ordering
      end
    end
  end
end

#get_features ⇒ Object 



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# File 'lib/nswtopo/layer/spot.rb', line 127

def get_features
  selected, rejected, remaining = [], Set[], AVLTree.new
  index = RTree.load(candidates, &:bounds)

  log_update "%s: choosing candidates" % @name
  candidates.to_set.each do |candidate|
    buffer = NOISE_MM * @map.scale / 1000.0
    index.search(candidate.bounds(buffer)).each do |other|
      next unless candidate["knoll"] ^ other["knoll"]
      next if [candidate, other].map(&:coordinates).distance > buffer
      rejected << candidate << other
    end
  end.difference(rejected).each do |candidate|
    buffer = @spacing * @map.scale / 1000.0
    index.search(candidate.bounds(buffer)).each do |other|
      next if other == candidate
      next if rejected === other
      next if [candidate, other].map(&:coordinates).distance > buffer
      candidate.conflicts << other
    end
  end.each do |candidate|
    remaining << candidate
  end

  while chosen = remaining.first
    log_update "%s: choosing candidates: %i remaining" % [@name, remaining.count]
    selected << chosen
    removals = Set[chosen] | chosen.conflicts
    removals.each do |candidate|
      remaining.delete candidate
    end.map(&:conflicts).inject(&:|).subtract(removals).each do |other|
      remaining.delete other
      other.conflicts.subtract removals
      remaining.insert other
    end
  end

  selected.each do |feature|
    feature.properties.replace "label" => feature["elevation"].round
  end.yield_self do |features|
    GeoJSON::Collection.new @map.projection, features
  end
end

#margin ⇒ Object 



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# File 'lib/nswtopo/layer/spot.rb', line 21

def margin
  { mm: 3 * @smooth }
end

#ordering ⇒ Object 



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# File 'lib/nswtopo/layer/spot.rb', line 67

def ordering
  @ordering ||= case @prefer
  when "knolls" then Candidate::PreferKnolls
  when "saddles" then Candidate::PreferSaddles
  else Candidate::PreferNeither
  end
end

#raster_locations(path, pixels) ⇒ Object 



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# File 'lib/nswtopo/layer/spot.rb', line 33

def raster_locations(path, pixels)
  OS.gdaltransform "-output_xy", path do |stdin|
    pixels.each { |pixel| stdin.puts "%i %i" % pixel }
  end.each_line.map do |line|
    line.chomp.split(?\s).map(&:to_f)
  end
end

#raster_values(path, pixels) ⇒ Object 



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# File 'lib/nswtopo/layer/spot.rb', line 25

def raster_values(path, pixels)
  OS.gdallocationinfo "-valonly", path do |stdin|
    pixels.each { |pixel| stdin.puts "%i %i" % pixel }
  end.each_line.map do |line|
    Float(line) rescue nil
  end
end