Class: GeoModel

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
app/models/geo_model.rb

Direct Known Subclasses

SearchModel

Constant Summary collapse

@@default_client_srid =

default client_srid

21781
@@default_rgeo_factory =

default geo factory

RGeo::Cartesian.factory(:srid => 21781, :proj4 => '+proj=somerc +lat_0=46.95240555555556 +lon_0=7.439583333333333 +k_0=1 +x_0=600000 +y_0=200000 +ellps=bessel +towgs84=674.4,15.1,405.3,0,0,0,0 +units=m +no_defs')

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.area_field(client_srid = nil) ⇒ Object

NOTE: area in client_srid units



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# File 'app/models/geo_model.rb', line 64

def self.area_field(client_srid=nil)
  # transform geometry to client_srid first
  "ST_Area(#{transform_geom_sql(geometry_field, srid, client_srid)}) AS area"
end

.bbox_filter(params) ⇒ Object

based on mapfish_filter



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# File 'app/models/geo_model.rb', line 155

def self.bbox_filter(params)
  filter = scoped

  if params['bbox']
    x1, y1, x2, y2 = params['bbox'].split(',').collect(&:to_f)
    box = [[x1, y1], [x2, y2]]
    filter_geom = "'BOX3D(#{box[0].join(" ")},#{box[1].join(" ")})'::box3d"
  elsif params['polygon']
    filter_geom = "ST_GeomFromText('#{params['polygon']}')"
  end

  if filter_geom
    # transform filter geom to srid
    client_srid = params['srid'].blank? ? default_client_srid : params['srid'].to_i
    filter_geom = transform_geom_sql("ST_SetSRID(#{filter_geom}, #{client_srid})", client_srid, srid)
    filter = filter.where("ST_Intersects(#{geometry_field}, #{filter_geom})")
  end

  filter.limit(1000)
end

.can_edit?(ability) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/models/geo_model.rb', line 278

def self.can_edit?(ability)
  @layers ||= Layer.where(:table => self.table_name).all
  can_edit = false
  @layers.each do |layer|
    # check if any layer with this table is editable
    if ability.can?(:edit, layer)
      can_edit = true
      break
    end
  end
  can_edit
end

.default_client_srid ⇒ Object 



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# File 'app/models/geo_model.rb', line 477

def self.default_client_srid
  @@default_client_srid
end

.default_rgeo_factory ⇒ Object 



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# File 'app/models/geo_model.rb', line 489

def self.default_rgeo_factory
  @@default_rgeo_factory
end

.extent_field(client_srid = nil) ⇒ Object 



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# File 'app/models/geo_model.rb', line 58

def self.extent_field(client_srid=nil)
  # transform geometry to client_srid first
  "ST_Envelope(#{transform_geom_sql(geometry_field, srid, client_srid)}) AS extent"
end

.forbidden(ability) ⇒ Object 



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# File 'app/models/geo_model.rb', line 303

def self.forbidden(ability)
  if ability.nil?
    logger.info "----> Edit access forbidden without login"
  else
    logger.info "----> Edit access forbidden with roles #{ability.roles.collect(&:name).join('+')}!"
  end
  where('1=0') # No access
end

.geo_factory ⇒ Object 



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# File 'app/models/geo_model.rb', line 493

def self.geo_factory
  if self.rgeo_factory_generator == RGeo::ActiveRecord::DEFAULT_FACTORY_GENERATOR
    self.rgeo_factory_generator = RGeo::Geos.factory_generator
    rgeo_factory_settings.set_column_factory(table_name, geometry_column_name,
      default_rgeo_factory
    )
  end
  rgeo_factory_for_column(geometry_column_name)
end

.geojson_decode(json) ⇒ Object 



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# File 'app/models/geo_model.rb', line 176

def self.geojson_decode(json)
  geojson = JSON.parse(json)

  # get client_srid from GeoJSON CRS
  if geojson['crs'].blank?
    client_srid = default_client_srid
  else
    client_srid = geojson['crs']['properties']['name'].split(':').last rescue default_client_srid
    # use EPSG:4326 for 'urn:ogc:def:crs:OGC:1.3:CRS84'
    client_srid = 4326 if client_srid == 'CRS84'
  end

  # NOTE: use dummy factory to set client_srid for update_attributes_from_geojson_feature()
  RGeo::GeoJSON.decode(geojson, :geo_factory => RGeo::Cartesian.factory(:srid => client_srid))
end

.geometry_column ⇒ Object 



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# File 'app/models/geo_model.rb', line 30

def self.geometry_column
  col = columns_hash[geometry_column_name]
  col.instance_eval { @srid = srid }
  col
end

.geometry_column_info ⇒ Object 



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# File 'app/models/geo_model.rb', line 11

def self.geometry_column_info
  #spatial_column_info returns key/value list with geometry_column name as key
  #value example: {:srid=>21781, :type=>"MULTIPOLYGON", :dimension=>2, :has_z=>false, :has_m=>false, :name=>"the_geom"}
  #We take the first matching entry
  @geometry_column_info ||= connection.spatial_column_info(table_name).values.first
end

.geometry_column_name ⇒ Object 



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# File 'app/models/geo_model.rb', line 18

def self.geometry_column_name
  geometry_column_info[:name]
end

.geometry_field ⇒ Object 



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# File 'app/models/geo_model.rb', line 54

def self.geometry_field
  "#{table_name}.#{connection.quote_column_name(geometry_column_name)}"
end

.geometry_type ⇒ Object 



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# File 'app/models/geo_model.rb', line 22

def self.geometry_type
  geometry_column_info[:type]
end

.identify_filter(searchgeo, radius, nearest = false, client_srid = nil) ⇒ Object

NOTE: radius in srid units



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# File 'app/models/geo_model.rb', line 70

def self.identify_filter(searchgeo, radius, nearest=false, client_srid=nil)
  filter = scoped

  client_srid ||= default_client_srid

  if searchgeo[0..3] == "POLY"
    logger.debug "*** POLY-query: #{searchgeo} ***"
    search_geom = "ST_GeomFromText('#{searchgeo}', #{client_srid})"
    center = "ST_Centroid(#{search_geom})"
  else
    if searchgeo.split(',').length == 3
      logger.debug "*** CIRCLE-query: #{searchgeo} ***"
      x1, y1, r  = searchgeo.split(',').collect(&:to_f)
      center = "ST_GeomFromText('POINT(#{x1} #{y1})', #{client_srid})"
      # NOTE: circle as buffer with radius in client_srid units
      search_geom = "ST_Buffer(#{center}, #{r}, 32)"
      radius = 0
    else
      logger.debug "*** BBOX-query: #{searchgeo} ***"
      x1, y1, x2, y2 = searchgeo.split(',').collect(&:to_f)
      search_geom = "ST_GeomFromText('POINT(#{x1+(x2-x1)/2} #{y1+(y2-y1)/2})', #{client_srid})"
      center = search_geom
    end
  end

  # transform search geometry to srid
  search_geom = transform_geom_sql(search_geom, client_srid, srid)

  # get features within radius in srid units
  filter = filter.where("ST_DWithin(#{geometry_field}, #{search_geom}, #{radius})")

  if nearest
    logger.debug "*** query nearest ***"
    # transform center to srid
    center = transform_geom_sql(center, client_srid, srid)
    # get min dist
    min_dist = filter.select("Min(ST_Distance(#{geometry_field}, #{center})) AS min_dist").first
    unless min_dist.nil?
      logger.debug "*** min_dist = #{min_dist.min_dist} ***"
      if min_dist.min_dist.to_f == 0
        # center of the search geometry is within a feature (may be overlapping features)
        filter = filter.where("ST_Within(#{center}, #{geometry_field})")
      else
        # get the feature nearest to the center of the search geometry
        filter = filter.order("ST_Distance(#{geometry_field}, #{center})").limit(1)
      end
    end
    # else no features in filter
  else
    # order by distance to center
    center = transform_geom_sql(center, client_srid, srid)
    filter = filter.order("ST_Distance(#{geometry_field}, #{center})")
  end

  filter
end

.select_geojson_geom(client_srid = nil) ⇒ Object

select transformed geometry as GeoJSON



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# File 'app/models/geo_model.rb', line 193

def self.select_geojson_geom(client_srid=nil)
  # transform geometry to client_srid
  geom_sql = transform_geom_sql("#{geometry_field}", srid, client_srid)
  # select geometry as GeoJSON
  scoped.select("ST_AsGeoJSON(#{geom_sql}) AS geojson_geom, 'EPSG:' || #{client_srid || srid} AS geojson_srid")
end

.set_default_client_srid(client_srid) ⇒ Object 



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# File 'app/models/geo_model.rb', line 473

def self.set_default_client_srid(client_srid)
  @@default_client_srid = client_srid
end

.set_default_rgeo_factory(factory) ⇒ Object 



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# File 'app/models/geo_model.rb', line 485

def self.set_default_rgeo_factory(factory)
  @@default_rgeo_factory = factory
end

.srid ⇒ Object 



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# File 'app/models/geo_model.rb', line 26

def self.srid
  geometry_column_info[:srid]
end

.transform_geom_sql(geom_sql, geom_srid, target_srid) ⇒ Object

generate SQL fragment for transforming input geometry geom_sql from geom_srid to target_srid



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# File 'app/models/geo_model.rb', line 37

def self.transform_geom_sql(geom_sql, geom_srid, target_srid)
  if geom_srid.nil? || target_srid.nil? || geom_srid == target_srid
    # no transformation
  else
    # transform to target SRID
    if target_srid == 2056 && geom_srid == 21781
      geom_sql = "ST_GeomFromEWKB(ST_Fineltra(#{geom_sql}, 'chenyx06_triangles', 'geom_lv03', 'geom_lv95'))"
    elsif target_srid == 21781 && geom_srid == 2056
      geom_sql = "ST_GeomFromEWKB(ST_Fineltra(#{geom_sql}, 'chenyx06_triangles', 'geom_lv95', 'geom_lv03'))"
    else
      geom_sql = "ST_Transform(#{geom_sql}, #{target_srid})"
    end
  end

  geom_sql
end

.user_filter(ability) ⇒ Object

apply user filter for editing Override in descendant classes



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# File 'app/models/geo_model.rb', line 293

def self.user_filter(ability)
  if ability.nil?
    forbidden(ability)
  elsif can_edit?(ability)
    scoped #No filter
  else
    forbidden(ability)
  end
end

.validate_feature(feature, geojson_data) ⇒ Object 



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# File 'app/models/geo_model.rb', line 380

def self.validate_feature(feature, geojson_data)
  if feature.nil? || (feature.is_a?(RGeo::GeoJSON::Feature) && feature.geometry.is_empty?)
    geojson = JSON.parse(geojson_data)
    if geojson['type'].blank? || geojson['type'] != 'Feature'
      # not a GeoJSON
      return {
        :error => "Invalid GeoJSON"
      }
    else
      # invalid geometry
      # NOTE: RGeo::GeoJSON.decode is nil or feature geometry is empty if geometry is invalid
      errors = []
      begin
        errors = validate_geometry(geojson)
      rescue => err
        logger.error "Error while checking GeoJSON geometries:\n#{err.message}"
      end

      return {
        :error => "Invalid geometry",
        :geometry_errors => errors
      }
    end
  elsif !feature.is_a? RGeo::GeoJSON::Feature
    # not a GeoJSON Feature
    return {
      :error => "GeoJSON is not a Feature"
    }
  end

  # validate geometry type
  error = validate_geometry_type(feature)
  unless error.nil?
    return {
      :error => "Invalid geometry type",
      :geometry_errors => [error]
    }
  end

  # validations OK
  return nil
end

.validate_feature_collection(feature_collection, geojson_data) ⇒ Object

GeoJSON validations



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# File 'app/models/geo_model.rb', line 326

def self.validate_feature_collection(feature_collection, geojson_data)
  if feature_collection.nil?
    # not a GeoJSON
    return {
      :error => "Invalid GeoJSON"
    }
  elsif !feature_collection.is_a? RGeo::GeoJSON::FeatureCollection
    # not a GeoJSON FeatureCollection
    return {
      :error => "GeoJSON is not a FeatureCollection"
    }
  elsif !feature_collection.any? || feature_collection.select {|feature| feature.geometry.is_empty?}.any?
    # no features or invalid geometries
    # NOTE: RGeo::GeoJSON.decode or feature geometry is empty if geometry is invalid
    errors = []
    begin
      geojson = JSON.parse(geojson_data)
      if geojson['features'].blank?
        return {
          :error => "No GeoJSON features found"
        }
      end

      geojson['features'].each do |feature|
        feature_errors = validate_geometry(feature)
        errors += feature_errors if feature_errors.any?
      end
    rescue => err
      logger.error "Error while checking GeoJSON geometries:\n#{err.message}"
    end

    return {
      :error => "Invalid geometry",
      :geometry_errors => errors
    }
  end

  # validate geometry type
  errors = []
  feature_collection.each do |feature|
    error = validate_geometry_type(feature)
    errors << error unless error.nil?
  end
  if errors.any?
    return {
      :error => "Invalid geometry type",
      :geometry_errors => errors
    }
  end

  # validations OK
  return nil
end

.validate_geometry(feature) ⇒ Object 



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# File 'app/models/geo_model.rb', line 423

def self.validate_geometry(feature)
  errors = []

  # validate geometry
  wkt_geom = ""
  sql = "WITH feature AS (SELECT ST_GeomFromGeoJSON(?) AS geom) SELECT valid, reason, ST_AsText(location) AS location, ST_AsText(geom) AS wkt_geom FROM feature, ST_IsValidDetail(geom)"
  sql = send :sanitize_sql, [sql, feature['geometry'].to_json]
  results = connection.execute(sql)
  results.each do |result|
    if result['valid'] == 'f'
      error = {}
      error[:id] = feature['id'] unless feature['id'].blank?
      error[:reason] = result['reason'] unless result['reason'].blank?
      error[:location] = result['location'] unless result['location'].blank?
      errors << error
    end
    wkt_geom = result['wkt_geom']
  end

  # check for repeated vertices
  wkt_geom.gsub(/(?<=\()([\d\.,\s]+)(?=\))/) do |m|
    vertices = m.split(',')
    vertices.each_with_index do |v, i|
      if i > 0 && vertices[i-1] == v
        errors << {
          :reason => "Duplicated point",
          :location => "POINT(#{v})"
        }
      end
    end
  end

  errors
end

.validate_geometry_type(feature) ⇒ Object 



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# File 'app/models/geo_model.rb', line 458

def self.validate_geometry_type(feature)
  if geometry_type != 'GEOMETRY' && feature.geometry.geometry_type.to_s.upcase != geometry_type
    error = {}
    error[:id] = feature.feature_id unless feature.feature_id.blank?
    error.merge({
      :reason => "Invalid geometry type: #{feature.geometry.geometry_type}",
      :location => feature.geometry.as_text
    })
  end
end

Instance Method Details

#bbox(client_srid = nil) ⇒ Object

Custom identify query def self.identify_query(layer, query_topic, searchgeom, ability, user, client_srid=nil)

# default layer query
query_fields = (["#{self.table_name}.#{self.primary_key}"] + layer.ident_fields_for(ability).split(',') + [self.extent_field(client_srid), self.area_field(client_srid)]).join(',')
features = scoped.identify_filter(searchgeom, layer.searchdistance, nil, client_srid).where(layer.where_filter).select(query_fields)
features.all

end



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# File 'app/models/geo_model.rb', line 135

def bbox(client_srid=nil)
  if respond_to?('extent')
    # use extent from select(extent_field)
    envelope = GeoRuby::SimpleFeatures::Geometry.from_hex_ewkb(extent).envelope
    [envelope.lower_corner.x, envelope.lower_corner.y, envelope.upper_corner.x, envelope.upper_corner.y]
  else
    # get Box2D for this feature
    # transform geometry to client_srid first
    box_query = "Box2D(#{self.class.transform_geom_sql(self.class.geometry_field, self.class.srid, client_srid)})"
    extent = self.class.select("ST_XMin(#{box_query}), ST_YMin(#{box_query}), ST_XMax(#{box_query}), ST_Ymax(#{box_query})").find(id)
    [
      extent.st_xmin.to_f,
      extent.st_ymin.to_f,
      extent.st_xmax.to_f,
      extent.st_ymax.to_f
    ]
  end
end

#csv_header ⇒ Object

header for CSV export



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# File 'app/models/geo_model.rb', line 313

def csv_header
  #empty by default
  []
end

#csv_row ⇒ Object

row values for CSV export



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# File 'app/models/geo_model.rb', line 319

def csv_row
  #empty by default
  []
end

#customize_geojson(geojson, options = {}) ⇒ Object

customize GeoJSON contents, e.g. to add custom properties or fields override in descendant classes



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# File 'app/models/geo_model.rb', line 202

def customize_geojson(geojson, options={})
  geojson
end

#modified_by(user) ⇒ Object

update modification attributes (changed_by, etc.) Override in descendant classes



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# File 'app/models/geo_model.rb', line 274

def modified_by(user)
  #none by default
end

#to_geojson(options = {}) ⇒ Object 



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# File 'app/models/geo_model.rb', line 206

def to_geojson(options={})
  only = options.delete(:only)
  geojson = { :type => 'Feature' }
  geojson[:properties] = attributes.delete_if do |name, value|
    if name == self.class.geometry_column_name
      geojson[:geometry] = value
      true
    elsif name == 'geojson_geom' || name == 'geojson_srid'
      # skip helper fields
      true
    elsif name == self.class.primary_key then
      geojson[:id] = value
      true
    elsif only
      !only.include?(name.to_sym)
    end
  end

  geojson = customize_geojson(geojson, options)

  if attributes.has_key?('geojson_geom')
    # dummy geometry (ignore value from geometry column)
    geojson[:geometry] = {}

    unless options[:skip_feature_crs]
      # add GeoJSON CRS unless part of a FeatureCollection
      geojson[:crs] = {
        :type => 'name',
        :properties => {
          :name => attributes['geojson_srid']
        }
      }
    end

    # convert to JSON and replace geometry with GeoJSON field from query
    geojson.to_json.sub(/"geometry":{}/, "\"geometry\":#{attributes['geojson_geom']}")
  else
    geojson.to_json
  end
end

#update_attributes_from_geojson_feature(feature, user) ⇒ Object 



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# File 'app/models/geo_model.rb', line 247

def update_attributes_from_geojson_feature(feature, user)
  attr = feature.properties

  unless feature.geometry.nil?
    # get client_srid from RGeo geometry
    client_srid = feature.geometry.srid
    if client_srid != self.class.srid
      # transform feature geometry to srid
      geom_sql = self.class.transform_geom_sql("ST_GeomFromText('#{feature.geometry.as_text}', #{client_srid})", client_srid, self.class.srid)
      sql = "SELECT ST_AsText(#{geom_sql}) AS wkt_geom"
      results = connection.execute(sql)
      results.each do |result|
        attr[self.class.geometry_column_name] = self.class.geo_factory.parse_wkt(result['wkt_geom'])
      end
    else
      # no transformation
      attr[self.class.geometry_column_name] = feature.geometry
    end
  end

  ok = update_attributes(attr)
  modified_by(user)
  ok
end