The following example shows how visualization APIs can be used from the openLCA
Python API. In the example, all output amounts of
Emission to air/unspecified/Chromium VI
are collected from a database,
transformed with f(x) = log10(x * 1e15)
to make a nice distribution, and
shown in a histogram using the
Google Chart API.
Therefore, an HTML page is generated that is loaded in a JavaFX WebView in a
separate window.
With ecoinvent 3.3 (apos), the result looks like this:
Here is the full Python code:
import json
import math
from javafx.embed.swt import FXCanvas
from org.eclipse.swt.widgets import Display, Shell
from org.eclipse.swt import SWT
from org.eclipse.swt.layout import FillLayout
from org.openlca.core.database import NativeSql, FlowDao
from org.openlca.app.util import UI
def get_flow():
""" Get the flow `Emission to air / unspecified / Chromium VI` from the
database.
"""
flows = FlowDao(db).getForName('Chromium VI')
for flow in flows:
c = flow.category
if c is None or c.name != 'unspecified':
continue
c = c.category
if c is None or c.name != 'Emission to air':
continue
return flow
def get_results():
""" Get the values for the flow from the process inputs and outputs and
transform them: f(x) = log10(x * 1e15).
"""
def collect_results(record):
results.append([math.log10(record.getDouble(1) * 1e15)])
return True
chrom6 = get_flow()
log.info(chrom6.name)
results = [['Chromium VI']]
query = 'select resulting_amount_value from tbl_exchanges where f_flow = %i' % chrom6.id
NativeSql.on(db).query(query, collect_results)
log.info('{} results collected', len(results))
return results
def make_html(results):
""" Generate the HTML page for the data. """
html = '''<html>
<head>
<script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
<script type="text/javascript">
google.charts.load("current", {packages:["corechart"]});
google.charts.setOnLoadCallback(drawChart);
function drawChart() {
var data = google.visualization.arrayToDataTable(%s);
var options = {
title: 'Chromium VI',
legend: { position: 'none' },
hAxis: {
ticks: [0, 2, 4, 6, 8, 10, 12, 14]
}
};
var chart = new google.visualization.Histogram(
document.getElementById('chart_div'));
chart.draw(data, options);
}
</script>
</head>
<body>
<div id="chart_div" style="width: 900px; height: 500px;"></div>
</body>
</html>
''' % json.dumps(results)
return html
def main():
""" Create the results, HTML, and window with the WebView and set the HTML
content of the WebView.
"""
results = get_results()
html = make_html(results)
shell = Shell(Display.getDefault())
shell.setText('Chromium VI')
shell.setSize(800, 600)
shell.setLayout(FillLayout())
canvas = FXCanvas(shell, SWT.NONE)
web_view = UI.createWebView(canvas)
web_view.loadContent(html)
shell.open()
if __name__ == '__main__':
Display.getDefault().asyncExec(main)