Power 10 logarithmic Axis Scale

Answered

Hi,

I’ve had a request from the client of our app to set logarithmic axis to have their major ticks at powers of 10, for example 0.1|1|10|100|1000|10000 – they would be expressed as 1e-1|1e0|1e1|1e2|1e3|1e4…. etc.

Is this possible within the current implantation of the logarithmic axis?

Cheers,

Version

2.1.2301

JavaScript

Adam Stone asked 2 years ago

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Answers (4)

Best Answer

OK so you need another API to control the frequency of tick labels

Try this: Axis Ticks – Gridline and Label Spacing (Interval)

Axis.majorDelta and minorDelta will give you coarse grain control over the output ticks (labels) on an axis.

For a non-log NumericAxis a majorDelta = 1 means “Place a label at every 1”
For logarithmic axis with logBase = 10, majorDelta = 1 means “Place a label at every 10^1”

You can also have precise control over the axis ticks using the TickProvider API.

I’ve updated the Logarithmic Axis example here to include these two features.

const yAxis = new LogarithmicAxis(wasmContext, {
    logBase: 10,
    labelFormat: ENumericFormat.Scientific,
    majorDelta: 1,
    minorDelta: 0.1,
    autoTicks: false, // When true, calculate major/minor delta. Otherwise use user-provided values
});

This results in the following output

Javascript Logarithmic Axis chart

Best regards
Andrew

Andrew Burnett-Thompson answered 2 years ago

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Hi Adam,

yes it is, we call this scientific notation. Take a look at the JavaScript Logarithmic Axis documentation.

import {SciChartSurface} from "scichart/Charting/Visuals/SciChartSurface";
import {EAxisAlignment} from "scichart/types/AxisAlignment";
import {ENumericFormat} from "scichart/types/NumericFormat";
import {LogarithmicAxis} from "scichart/Charting/Visuals/Axis/LogarithmicAxis";
import {NumberRange} from "scichart/Core/NumberRange";
sciChartSurface.xAxes.add(new LogarithmicAxis(wasmContext, {
    axisTitle: "Log(10) Axis",
    axisAlignment: EAxisAlignment.Bottom,
    labelFormat: ENumericFormat.Scientific,
    logBase: 10,
    visibleRange: new NumberRange(1, 1E6)
}));

By specifying labelFormat = ENumericFormat.Scientific and logBase = 10, you will get numbers formatted as 1×10^1, 1×10^2

With ENumericFormat.Exponential you will get numbers formatted as 1E0, 1E1, 1E2

Does this help?

Best regards
Andrew

Andrew Burnett-Thompson answered 2 years ago

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Hi Andrew,

Thanks for your response. I’ve recreated this in our product and it’s almost what I needed. I’ve attached a screenshot that shows what it’s produced with our data. Whilst I can see the 1x10x1 1x10x0 etc I also get 3x10xX in-between each of those ticks. The same happens with Exponential with the 3.2e-X marks. Is there a way to force the chart to omit this and always stick with 1e/1×10 ticks?

I’ve also tried experimenting with the ELogarithmicMajorTickMode and ELogarithmicMinorTickModes but unless I’ve misunderstood them I’m unable to reproduce what I need.

Regards,

Adam

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