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0 votes


I’ve the following problem.

We have an application where we have many spectrums (frequency or order spectrums). To get a better overview and to select one for a more detailed analysis, we would like to display them as a waterfall chart. A spectrum always has a high resolution of 32768 points. If I now display between 60 and 100 spectrums in a waterfall chart, it takes quite a long time to render this and it is almost impossible to operate the chart.

However, a high-resolution spectrum is not required for a good overview in the waterfall diagram. Therefore my idea is to resample every single spectrum to e.g. 8192 points and then display it in the waterfall diagram.

Is there a possibility to use the internal SciChart resampler (e.g. Min/Max) or do I have to develop an own algorithm for this?

Or does a similar function already exist in SciChart?


0 votes

I have created a heatmap chart with values for the data series with four vertical lines of width 1. When the width of data series is smaller than width of SciChartSurface in pixels the four lines are clearly visible. However when I increase the width of data series to be bigger than the width in pixels, then some lines disappear, even though I’ve set the re-sampling mode to ResamplingMode.Max.

I wasn’t able to attach images to the post (got a Forbidden error), so I’ve uploaded them to Imagur:
Missing Lines
Visible lines

Here is the code from which the screen shots were made:

import android.os.Bundle
import com.scichart.charting.model.dataSeries.UniformHeatmapDataSeries
import com.scichart.charting.visuals.SciChartSurface
import com.scichart.charting.visuals.renderableSeries.ColorMap
import com.scichart.drawing.utility.ColorUtil
import kotlin.math.roundToInt

const val WIDTH = 2000
const val HEIGHT = 50

class MainActivity : AppCompatActivity()
    override fun onCreate(savedInstanceState: Bundle?)



        val chartSurface = findViewById<SciChartSurface>(
        val chartBuilder = SciChartBuilder.instance()

        val xAxis = chartBuilder.newNumericAxis().build()
        val yAxis = chartBuilder.newNumericAxis().build()

        val dataSeries = UniformHeatmapDataSeries<Int, Int, Int>(Int::class.javaObjectType, Int::class.javaObjectType, Int::class.javaObjectType, WIDTH, HEIGHT)
        for (x in 0 until WIDTH)
            for (y in 0 until HEIGHT)
                val value = when (x)
                    (0.25 * WIDTH).roundToInt(),
                    (0.5 * WIDTH).roundToInt(),
                    (0.75 * WIDTH).roundToInt() -> 50
                    else                        -> 0
                dataSeries.updateZAt(x, y, value)

        val series = chartBuilder.newUniformHeatmap()
            .withColorMap(ColorMap(intArrayOf(ColorUtil.DarkBlue, ColorUtil.CornflowerBlue, ColorUtil.DarkGreen, ColorUtil.Chartreuse, ColorUtil.Yellow, ColorUtil.Red), floatArrayOf(0f, 0.2f, 0.4f, 0.6f, 0.8f, 1f)))

        chartSurface.suspendUpdates().use {
0 votes

Hello support team.

I have a question about the resampling modes and their behavior.
I have a LineRenderableSeries with the resampling mode.mid. Therefore, depending on the zoom level and available pixels of the display screen, the information of the min and max values are lost. I had the idea to create a second LineRenderableSeries with the Opacity 0.5 and the ResamplingMode.Min Max. Thus I have behind the main line with the resampling mode.mid a “cloud” with the MinMax info. This allows the user to see this information as well. However, I would deactivate this cloud if it is not necessary due to the zoom level and the pixels.
How can I request this from SciChartControl? Or does it make more sense to use a different functionality?
I use the Mvvm classes LineRenderableSeriesViewModel, and XyDataSeries.

Thank you very much!

1 vote

I would like to stop the user from trying to load datas that are so large that when zoomed out it becomes confusing. I thought that we could use the none resampling mode but that means that the chart would load all data points and I think that this could affect performance. No matter the resampling mode, eventually the dataset will be so large that if the user zooms out, the chart will display a confusing image.

What is the best practice for this type of situation? I was thinking that perhaps we should limit the zoom based on data size. Perhaps there is a better idea out there?


  • ryan01 asked 4 years ago
  • last active 4 years ago
2 votes
0 answers

Hi SciChart-Team!

This is more a feature than a support request but I could not find a more suitable place for it.

One of the strengths of SciCharts is its ability to select – use case dependend – the most appropriate resampling technique for drawing from a wide variety of options. Currently I depict a 2-dimensional empirical probablity density function (PDF) with the heatmap. The best way for a sub-/resampling would be a kind of “Sum”-Mode to represent the new “Cell-Count” and to prevent the disappearance of strongly localized, concentrated PDF-spikes if the window is scaled down. Maybe it is possible to implement such a resampling mode for the heatmap in a future release?

Due to the lack of a “Sum”-Mode I tried to use “Max”-Mode to keep the PDF-Spikes visible after scaling down but that didn’t worked as I expected. Was my expectation wrong? I know I can do it by myself and recalculate the PDF for the new heatmap size, create a new Heatmap2DArrayDataSeries … etc. but it would be nice if it would work out of the box.



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