Django-Chartit

Django-Chartit can be used to plot the data on web pages from various models. The charts are rendered using the Highcharts and jQuery JavaScript libraries. Data in your database can be plotted as simple line charts, column charts, area charts, scatter plots, and many more chart types. Data can also be plotted as Pivot Charts where the data is grouped and/or pivoted by specific column(s).

Features

  • Can plot charts from models.
  • Can plot data from multiple models on the same axis on a chart.
  • Can plot pivot charts from models. Data can be pivoted by multiple columns.
  • Can legend pivot charts by multiple columns.
  • Can combine data from multiple models to plot on same pivot charts.
  • Can plot a pareto chart, paretoed by a specific column.
  • Can plot only a top few items per category in a pivot chart.

Installation

You can install Django-Chartit from PyPI. Just do

$ pip install django_chartit

You also need supporting JavaScript libraries. See the Required JavaScript Libraries section for more details.

How to Use

Plotting a chart or pivot chart on a webpage involves the following steps.

  1. Create a DataPool or PivotDataPool object that specifies what data you need to retrieve and from where.
  2. Create a Chart or PivotChart object to plot the data in the DataPool or PivotDataPool respectively.
  3. Return the Chart/PivotChart object from a django view function to the django template.
  4. Use the load_charts template tag to load the charts to HTML tags with specific ids.

It is easier to explain the steps above with examples. So read on.

How to Create Charts

Here is a short example of how to create a line chart. Let’s say we have a simple model with 3 fields - one for month and two for temperatures of Boston and Houston.

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class MonthlyWeatherByCity(models.Model):
    month = models.IntegerField()
    boston_temp = models.DecimalField(max_digits=5, decimal_places=1)
    houston_temp = models.DecimalField(max_digits=5, decimal_places=1)

And let’s say we want to create a simple line chart of month on the x-axis and the temperatures of the two cities on the y-axis.

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from chartit import DataPool, Chart

def weather_chart_view(request):
    #Step 1: Create a DataPool with the data we want to retrieve.
    weatherdata = \
        DataPool(
           series=
            [{'options': {
               'source': MonthlyWeatherByCity.objects.all()},
              'terms': [
                'month',
                'houston_temp',
                'boston_temp']}
             ])

    #Step 2: Create the Chart object
    cht = Chart(
            datasource = weatherdata,
            series_options =
              [{'options':{
                  'type': 'line',
                  'stacking': False},
                'terms':{
                  'month': [
                    'boston_temp',
                    'houston_temp']
                  }}],
            chart_options =
              {'title': {
                   'text': 'Weather Data of Boston and Houston'},
               'xAxis': {
                    'title': {
                       'text': 'Month number'}}})

    #Step 3: Send the chart object to the template.
    return render_to_response({'weatherchart': cht})

And you can use the load_charts filter in the django template to render the chart.

<head>
    <!-- code to include the highcharts and jQuery libraries goes here -->
    <!-- load_charts filter takes a comma-separated list of id's where -->
    <!-- the charts need to be rendered to                             -->
    {% load chartit %}
    {{ weatherchart|load_charts:"container" }}
</head>
<body>
    <div id='container'> Chart will be rendered here </div>
</body>

How to Create Pivot Charts

Here is an example of how to create a pivot chart. Let’s say we have the following model.

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class DailyWeather(models.Model):
    month = models.IntegerField()
    day = models.IntegerField()
    temperature = models.DecimalField(max_digits=5, decimal_places=1)
    rainfall = models.DecimalField(max_digits=5, decimal_places=1)
    city = models.CharField(max_length=50)
    state = models.CharField(max_length=2)

We want to plot a pivot chart of month (along the x-axis) versus the average rainfall (along the y-axis) of the top 3 cities with highest average rainfall in each month.

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from chartit import PivotDataPool, PivotChart

def rainfall_pivot_chart_view(request):
    #Step 1: Create a PivotDataPool with the data we want to retrieve.
    rainpivotdata = \
        PivotDataPool(
           series =
            [{'options': {
               'source': DailyWeather.objects.all(),
               'categories': ['month']},
              'terms': {
                'avg_rain': Avg('rainfall'),
                'legend_by': ['city'],
                'top_n_per_cat': 3}}
             ])

    #Step 2: Create the PivotChart object
    rainpivcht = \
        PivotChart(
            datasource = rainpivotdata,
            series_options =
              [{'options':{
                  'type': 'column',
                  'stacking': True},
                'terms':[
                  'avg_rain']}],
            chart_options =
              {'title': {
                   'text': 'Rain by Month in top 3 cities'},
               'xAxis': {
                    'title': {
                       'text': 'Month'}}})

    #Step 3: Send the PivotChart object to the template.
    return render_to_response({'rainpivchart': rainpivcht})

And you can use the load_charts filter in the django template to render the chart.

<head>
    <!-- code to include the highcharts and jQuery libraries goes here -->
    <!-- load_charts filter takes a comma-separated list of id's where -->
    <!-- the charts need to be rendered to                             -->
    {% load chartit %}
    {{ rainpivchart|load_charts:"container" }}
</head>
<body>
    <div id='container'> Chart will be rendered here </div>
</body>

Demo

The above examples are just a brief taste of what you can do with Django-Chartit. For more examples and to look at the charts in actions, see the demo website.

Required JavaScript Libraries

The following JavaScript Libraries are required for using Django-Chartit.

Note

While Django-Chartit itself is licensed under the BSD license, Highcharts is licensed under the Highcharts license and jQuery is licensed under both MIT License and GNU General Public License (GPL) Version 2. It is your own responsibility to abide by respective licenses when downloading and using the supporting JavaScript libraries.

License

Copyright (c) 2011, Praveen Gollakota. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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