Class: Geos::LineString

Inherits:
Object
  • Object
show all
Defined in:
lib/geos/yaml/syck.rb,
lib/geos/line_string.rb

Instance Method Summary collapse

Instance Method Details

#as_geojson(options = {}) ⇒ Object Also known as: to_geojsonable 



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# File 'lib/geos/line_string.rb', line 11

def as_geojson(options = {})
  self.coord_seq.to_geojsonable(options)
end

#as_json(options = {}) ⇒ Object Also known as: to_jsonable 



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# File 'lib/geos/line_string.rb', line 6

def as_json(options = {})
  self.coord_seq.as_json(options)
end

#dump_points(cur_path = []) ⇒ Object

Dumps points similarly to the PostGIS ST_DumpPoints function.



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# File 'lib/geos/line_string.rb', line 17

def dump_points(cur_path = [])
  cur_path.concat(self.to_a)
end

#line_interpolate_point(fraction) ⇒ Object Also known as: interpolate_point 



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# File 'lib/geos/line_string.rb', line 67

def line_interpolate_point(fraction)
  if !fraction.between?(0, 1)
    raise ArgumentError.new("fraction must be between 0 and 1")
  end

  case fraction
    when 0
      self.start_point
    when 1
      self.end_point
    else
      length = self.length
      total_length = 0
      segs = self.num_points - 1

      segs.times do |i|
        p1 = self[i]
        p2 = self[i + 1]

        seg_length = p1.distance(p2) / length

        if fraction < total_length + seg_length
          dseg = (fraction - total_length) / seg_length

          args = []
          args << p1.x + ((p2.x - p1.x) * dseg)
          args << p1.y + ((p2.y - p1.y) * dseg)
          args << p1.z + ((p2.z - p1.z) * dseg) if self.has_z?

          args << { :srid => pick_srid_according_to_policy(self.srid) } unless self.srid == 0

          return Geos.create_point(*args)
        end

        total_length += seg_length
      end

      # if all else fails...
      self.end_point
  end
end

#snap_to_grid(*args) ⇒ Object 



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# File 'lib/geos/line_string.rb', line 61

def snap_to_grid(*args)
  ret = self.dup.snap_to_grid!(*args)
  ret.srid = pick_srid_according_to_policy(self.srid)
  ret
end

#snap_to_grid!(*args) ⇒ Object 



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# File 'lib/geos/line_string.rb', line 45

def snap_to_grid!(*args)
  if !self.empty?
    cs = self.coord_seq.snap_to_grid!(*args)

    if cs.length == 0
      @ptr = Geos.create_empty_line_string(:srid => self.srid).ptr
    elsif cs.length <= 1
      raise Geos::InvalidGeometryError.new("snap_to_grid! produced an invalid number of points in for a LineString - found #{cs.length} - must be 0 or > 1")
    else
      @ptr = Geos.create_line_string(cs).ptr
    end
  end

  self
end