class SVG::Graph::TimeSeries

For creating SVG plots of scalar temporal data

Synopsis

require 'SVG/Graph/TimeSeries'

# Data sets are x,y pairs
projection = ["6/17/72", 11,    "1/11/72", 7,    "4/13/04", 11,
             "9/11/01", 9,    "9/1/85", 2,    "9/1/88", 1,    "1/15/95", 13]
actual = ["8/1/73", 18,    "3/1/77", 15,    "10/1/98", 4,
          "5/1/02", 14,    "3/1/95", 6,    "8/1/91", 12,    "12/1/87", 6,
          "5/1/84", 17,    "10/1/80", 12]

title = "Ice Cream Cone Consumption"

graph = SVG::Graph::TimeSeries.new( {
  :width => 640,
  :height => 480,
  :graph_title => title,
  :show_graph_title => true,
  :no_css => true,
  :key => true,
  :scale_x_integers => true,
  :scale_y_integers => true,
  :min_x_value => 0,  # Integer, Time, or parseable by DateTime#parse
  :min_y_value => 0,  # Integer, Time, or parseable by DateTime#parse
  :show_data_values => true,
  :show_x_guidelines => true,
  :show_x_title => true,
  :x_title => "Time",
  :show_y_title => true,
  :y_title => "Ice Cream Cones",
  :y_title_text_direction => :bt,
  :stagger_x_labels => true,
  :x_label_format => "%m/%d/%y",
})

graph.add_data({
  :data => projection,
  :title => 'Projected',
  :template => '%d/%m/%y'
})

graph.add_data({
  :data => actual,
  :title => 'Actual',
  :template => '%d/%m/%y'
})

print graph.burn()

Description

Produces a graph of temporal scalar data.

Examples

www.germane-software/repositories/public/SVG/test/timeseries.rb

Notes

The default stylesheet handles upto 10 data sets, if you use more you must create your own stylesheet and add the additional settings for the extra data sets. You will know if you go over 10 data sets as they will have no style and be in black.

Unlike the other types of charts, data sets must contain x,y pairs:

[ "12:30", 2 ]          # A data set with 1 point: ("12:30",2)
[ "01:00",2, "14:20",6] # A data set with 2 points: ("01:00",2) and
                        #                           ("14:20",6)

Note that multiple data sets within the same chart can differ in length, and that the data in the datasets needn't be in order; they will be ordered by the plot along the X-axis.

The dates must be parseable by DateTime#parse or DateTime#strptime, but otherwise can be any order of magnitude (seconds within the hour, or years)

See also

Author

Sean E. Russell <serATgermaneHYPHENsoftwareDOTcom>

Copyright 2004 Sean E. Russell This software is available under the Ruby license

Attributes

popup_format[RW]

The formatting used for the popups. See x_label_format

timescale_divisions[RW]

Use this to set the spacing between dates on the axis. The value must be of the form “d+ ?(days|weeks|months|years|hours|minutes|seconds)?”

EG:

graph.timescale_divisions = "2 weeks"

will cause the chart to try to divide the X axis up into segments of two week periods.

x_label_format[RW]

The format string used to format the X axis labels. See Time::strformat, default: '%Y-%m-%d %H:%M:%S'

Public Instance Methods

add_data(data) click to toggle source

Add data to the plot.

d1 = [ "12:30", 2 ]          # A data set with 1 point: ("12:30",2)
d2 = [ "01:00",2, "14:20",6] # A data set with 2 points: ("01:00",2) and
                             #                           ("14:20",6)
graph.add_data(
  :data => d1,
  :title => 'One',
  :template => '%H:%M'  #template is optional
)
graph.add_data(
  :data => d2,
  :title => 'Two',
  :template => '%H:%M'
)

Note that the data must be in time,value pairs. The time may be any date in a format that is parseable by ParseDate, a Time object, or a number of seconds after the unix epoch.

Calls superclass method SVG::Graph::Plot#add_data
# File lib/SVG/Graph/TimeSeries.rb, line 152
def add_data data
  data[:data].each_index do |i|
    data[:data][i] = parse_time(data[:data][i], data[:template]).to_i if i % 2 == 0  # only even indices are time, odd indices are values
  end
  super(data)
end
set_defaults() click to toggle source

In addition to the defaults set by Graph::initialize and Plot::set_defaults, sets:

x_label_format

'%Y-%m-%d %H:%M:%S'

popup_format

'%Y-%m-%d %H:%M:%S'

Calls superclass method SVG::Graph::Plot#set_defaults
# File lib/SVG/Graph/TimeSeries.rb, line 107
def set_defaults
  super
  init_with(
    #:max_time_span     => '',
    :x_label_format     => '%Y-%m-%d %H:%M:%S',
    :popup_format       => '%Y-%m-%d %H:%M:%S',
  )
end

Protected Instance Methods

format(x, y, description) click to toggle source
# File lib/SVG/Graph/TimeSeries.rb, line 174
def format x, y, description
  info = [
    Time.at(x).strftime(popup_format),
    round_popups ? (y * 100).to_i / 100 : y,
    description
  ].compact.join(', ')
end
get_x_labels() click to toggle source
# File lib/SVG/Graph/TimeSeries.rb, line 182
def get_x_labels
  get_x_values.collect { |v| Time.at(v).strftime( x_label_format ) }
end
max_x_value=(value) click to toggle source

value must be Integer, Time, or parseable by DateTime#parse

# File lib/SVG/Graph/TimeSeries.rb, line 169
def max_x_value=(value)
  t = parse_time(value, nil)
  @max_x_value = t.to_i
end
min_x_value=(value) click to toggle source

value must be Integer, Time, or parseable by DateTime#parse

# File lib/SVG/Graph/TimeSeries.rb, line 163
def min_x_value=(value)
  t = parse_time(value, nil)
  @min_x_value = t.to_i
end

Private Instance Methods

get_x_values() click to toggle source
# File lib/SVG/Graph/TimeSeries.rb, line 208
def get_x_values
  rv = []
  min, max, @x_scale_division = x_label_range
  if timescale_divisions
    timescale_divisions =~ /(\d+) ?(day|week|month|year|hour|minute|second)?/
    division_units = $2 ? $2 : "day"
    amount = $1.to_i
    if amount
      step =  nil
      case division_units
      when "month"
        cur = min
        @x_scale_division = 365.25/12 * 24 * 60 * 60 * amount
        while cur < max
          rv << cur
          arr = Time.at( cur ).to_a
          arr[4] += amount
          if arr[4] > 12
            arr[5] += (arr[4] / 12).to_i
            arr[4] = (arr[4] % 12)
          end
          cur = Time.local(*arr).to_i
        end
      when "year"
        cur = min
        @x_scale_division = 365.25 * 24 * 60 * 60 * amount
        while cur < max
          rv << cur
          arr = Time.at( cur ).to_a
          arr[5] += amount
          cur = Time.local(*arr).to_i
        end
      when "week"
        step = 7 * 24 * 60 * 60 * amount
      when "day"
        step = 24 * 60 * 60 * amount
      when "hour"
        step = 60 * 60 * amount
      when "minute"
        step = 60 * amount
      when "second"
        step = amount
      end
      # only do this if division_units is not year or month. Those are done already above in the cases.
      min.step( max, step ) {|v| rv << v} if step
      @x_scale_division = step if step
      return rv
    end
  end
  min.step( max , @x_scale_division ) {|v| rv << v}
  return rv
end
parse_time(time, template) click to toggle source

Accepts date time as a string, number of seconds since the epoch, or Time object and returns a Time object. Raises an error if not a valid date time representation.

# File lib/SVG/Graph/TimeSeries.rb, line 191
def parse_time(time, template)
  case time
  when Time
    return time
  when String
    if template.kind_of? String
      return DateTime.strptime(time, template).to_time
    else
      return DateTime.parse(time).to_time
    end
  when Integer
    return Time.at(time)
  else
    raise "Can not parse time #{time.inspect}"
  end
end