Hi @aesi_geo​ if the ChartGenerator isn't accepting null values, then perhaps you could either use a Tester transformer to filter out the features that contain null values, or you could use a NullAttributeValueMapper to map those null values to a numerical value that works for your chart.

Unfortunately the missing values occur in the future so there are no values that can be assigned. I did try assigning the orange values to the blue values as a placeholder and putting the blue behind the orange, which almost hides them except for the connecting line from the last true blue value to the placeholder values.

if i place a tester to filter out the null values then the orange values are also lost. the chartgenerator has to have a full matching set of values to plot two line series :(

note: the missing blue values would come from a future staff gauge reading so it truly is null, the readings haven't been taken yet but there is a known future limit value.

Hello @aesi_geo​

The line graph in the HTMLReportGenerator is generated by scripts within the HTML. In order to get this as an image, you would have to download a utility application like wkhtmltoimage that renders HTML as image and save it. There is an FME Hub transformer called the HTML2ImageConvertor that should help with this workflow if you choose this method.

An alternative workaround that does not require any additional installation is to generate the chart for each data series separately but with the same settings such as min/max for axes, output image dimensions, etc. Then use a RasterExpressionEvaluator to combine the two images.

I have attached a workspace demonstrating the last workflow and I hope it helps.

This worked for me! thank you!!