I created some years ago with Google Chart this page
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I used wkhtmltoimage to convert this HTML page to a JPG. But I tried everything but this conversion free software (and also paid software) can't convert anymore this page to an image.
I tried other PHP chart, as Highcharts or Canvas JS, but I can't convert or export the entire page or a partial page in jpg format file.
We had only one serie, a string of numbers (temperature) in x-axis and a string of numbers (altitude) in y-axis. SPLINE is the best type of chart but if you have any other ideas, we can considered.
We need this conversion every 10 minutes for linking in our website/server. We can migrate to another PHP chart or other free source chart, but the result must be the same of Google charts.