taking GDAL/OGR ruby bindings for a spin

require 'gdal/ogr'
 
@global_extent = Array.new#(4, 0.0)
 
def dump_geom(geom, v)
  print "  Geometry type: ", geom.get_geometry_type, "\n"
  print "  Geometry name: ", geom.get_geometry_name, "\n" 
  extent = geom.get_envelope
  print "  BBox: ", extent[0], " ", extent[2], " ", extent[1], " ", extent[3], "\n" 
  for i in [0, 2]
    if (@global_extent[i].nil?) or @global_extent[i] > extent[i]
      @global_extent[i] = extent[i] 
    end
  end
  for i in [1, 3]
    if (@global_extent[i].nil?) or @global_extent[i] < extent[i]
      @global_extent[i] = extent[i] 
    end
  end
  if (geom.get_geometry_count > 0) 
    print "Geom Count = ", geom.get_geometry_count, "\n"
    geom.get_geometry_count.times do |i|
      dump_geom(geom.get_geometry_ref(i),v)
    end
  else
    if(!v)
      print "PointCount: ", geom.get_point_count,"\n" 
      geom.get_point_count.time do |i| 
      x = geom.get_x(i)
      y = geom.get_y(i)
      z = geom.get_x(i)
      print  " ",  x, " ", y, " ", z, "\n";
      end 
    end
  end
end
 
def dump_feature_data(feature, layer)
  feature_defn = layer.get_layer_defn  
  print "Feature ID: ", feature.get_fid, "\n"
  feature_defn.get_field_count.times do |i|
    print "Field ", i+1, "\n"
    field_defn = feature_defn.get_field_defn(i)
    print "  Field name: ",field_defn.get_name_ref,"\n" 
    type = field_defn.get_type
    print "  Field type: ", field_defn.get_field_type_name(type)," type\n"
    field = feature.get_field_as_string(i);
    print "  Field value: ", field,"\n"
  end
end
 
def dump_layer(layer)
  layer.reset_reading
  layer.get_feature_count.times do |i|
    feature = layer.get_feature(i)
    dump_feature_data(feature, layer)
    geom = feature.get_geometry_ref()
    do_not_show_vertices = 1
    if not geom.nil?
      dump_geom(geom, do_not_show_vertices)
    elsif geom.nil?
      print "*** expected geometry but got nill\n"
    end
end
end
 
if ARGV.length < 1
  print "Usage:  #$0", " <input_file>\n"
  exit
else
  filename = ARGV[0]
end
# driver = Gdal::Ogr.get_driver_by_name('ESRI Shapefile')
# open file as a OGR dataset
dataset = Gdal::Ogr.open(filename)
print "Looking at ", filename + " ...\n"
# get the number of layers
layer_num = dataset.get_layer_count 
layer_num.times do |i|
  layer = dataset.get_layer(i)  
  print "  looking at layer num: ", i+1 , "\n",
  "  Name: "+layer.get_name + ", Features: "+ layer.get_feature_count.to_s + "\n"
  dump_layer(layer)
end