Since i have volunteered to write the gdal ruby-binding test cases i thought it would be a good time to try out some of the ogr ruby-bindings. Charlie Savage has done a lot of work on the gdal SWIG ruby biniding and already written the test suite for OGR. Thanks to his excellent instructions on how to get started with writing the gdal-ruby test suit i was able to to easily convert Ari Jolma’s dumpall.pl to a ruby script to dump the contents of ogr (Vector) datastore.

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", "
\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