ESM: import Histogram from "@arcgis/core/widgets/Histogram.js";
CDN: const Histogram = await $arcgis.import("@arcgis/core/widgets/Histogram.js");
Class: @arcgis/core/widgets/Histogram
Since: ArcGIS Maps SDK for JavaScript 4.12
Renders a histogram to visualize the spread of a dataset based on bins representing buckets, or sub-ranges, of data. Each bin is defined by a minimum and maximum value and a total count.
You can generate the underlying histogram's bins with the histogram module. In this scenario, you can use the fromHistogramResult() helper method to conveniently create the histogram from the result object.
const params = {
layer: povLayer,
field: "POP_POVERTY",
normalizationField: "TOTPOP_CY",
numBins: 30
};
histogram(params)
.then(function(histogramResult) {
const histogram = Histogram.fromHistogramResult(histogramResult);
histogram.container = "histogram";
})
.catch(function(error) {
console.log("there was an error: ", error);
});
Other properties of this widget allow to display meaningful values on the histogram, such as the average and the dataLines properties.
See the image below for a summary of the configurable options available on this slider.
The barCreatedFunction property may be used to style the histogram bins based on the color of features in the renderer of a layer associated with the histogram.
new Histogram(properties)
Parameter
optionalSee the properties for a list of all the properties that may be passed into the constructor.
Example
// typical usage
const histogram = new Histogram({
bins: [{
minValue: 0,
maxValue: 20,
count: 1
}, {
minValue: 21,
maxValue: 40,
count: 60
},{
minValue: 41,
maxValue: 60,
count: 239
},{
minValue: 61,
maxValue: 80,
count: 88
},{
minValue: 81,
maxValue: 100,
count: 20
}],
max: 100,
min: 0,
average: 44
});Show inherited properties Hide inherited properties
Property DetailsThe statistical average of the data in the histogram. You would typically get this value from the avg property of SummaryStatisticsResult, which is the result of the summaryStatistics function.
When set, this value will render on the histogram with a symbol indicating it is the average.
Examples
// sets result returned from a smart mapping method
// to the histogram
histogram.average = response.statistics.avg;histogram.average = 34.5;Function for styling bars representing histogram bins. This can be used to color bins with the same color of features in the view that fall into bins representing the same range of data.
Example
histogram.barCreatedFunction = function(index, element){
let bin = histogram.bins[index];
let midValue = ((bin.maxValue - bin.minValue) / 2) + bin.minValue;
// colors the histogram bins with a custom function
// (not defined here for brevity of the snippet) for interpolating
// colors from data values to match the legend
let color = getColorFromValue(midValue);
element.setAttribute("fill", color.toHex());
};An array of objects representing each bin in the histogram. This information is typically returned from the histogram function.
Examples
// sets the bins of the histogram from the bins in the histogram() result
histogram.bins = histogramResult.bins;// Creates a histogram with 7 bins.
histogram.bins = [
{ minValue: 0, maxValue: 10, count: 4 },
{ minValue: 10.1, maxValue: 20, count: 14 },
{ minValue: 20.1, maxValue: 30, count: 9 },
{ minValue: 30.1, maxValue: 40, count: 34 },
{ minValue: 40.1, maxValue: 50, count: 351 },
{ minValue: 50.1, maxValue: 60, count: 100 },
{ minValue: 60.1, maxValue: 70, count: 1 }
];The ID or node representing the DOM element containing the widget. This property can only be set once. The following examples are all valid use case when working with widgets.
Examples
// Create the HTML div element programmatically at runtime and set to the widget's container
const basemapGallery = new BasemapGallery({
view: view,
container: document.createElement("div")
});
// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
position: "top-right"
});// Specify an already-defined HTML div element in the widget's container
const basemapGallery = new BasemapGallery({
view: view,
container: basemapGalleryDiv
});
// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
position: "top-right"
});
// HTML markup
<body>
<div id="viewDiv"></div>
<div id="basemapGalleryDiv"></div>
</body>// Specify the widget while adding to the view's UI
const basemapGallery = new BasemapGallery({
view: view
});
// Add the widget to the top-right corner of the view
view.ui.add(basemapGallery, {
position: "top-right"
});Function that fires each time a data line is created. You can use this to style individual dataLines on the data axis.
Example
histogram.dataLineCreatedFunction = function (lineElement, labelElement, index) {
lineElement.setAttribute("y2", "25%");
lineElement.classList.add("line-style");
};When set, renders lines on the histogram that indicate important or meaningful values to the end user.
The value on the data axis of the histogram where a line will be rendered.
optionalThe label associated with the line.
Examples
// will render lines at the 25th, 50th, 75th, and 99th percentiles
histogram.dataLines = [{
value: 30,
label: "25 pctl"
}, {
value: 45,
label: "50 pctl"
}, {
value: 65,
label: "75 pctl"
}, {
value: 89,
label: "99 pctl"
}];// calculate standard deviations from mean using stats
// returned from smart mapping statistic methods
const stddevs = smartMappingUtils.getDeviationValues(stats.stddev, stats.avg, 2);
histogram.dataLines = stddevs.map(function(stddev){
return {
value: stddev
};
});Inherited
Property declaredClass Stringreadonly
The name of the class. The declared class name is formatted as esri.folder.className.
Since: ArcGIS Maps SDK for JavaScript 4.27 Histogram since 4.12, icon added at 4.27.
Icon displayed in the widget's button.
Inherited
Property id String
The unique ID assigned to the widget when the widget is created. If not set by the developer, it will default to the container ID, or if that is not present then it will be automatically generated.
The widget's default label. This label displays when it is used within another widget, such as the Expand or LayerList widgets.
A function used to format labels on the histogram. Overrides the default label formatter.
Example
// For thumb values, rounds each label to whole numbers.
slider.labelFormatFunction = function(value) {
return value.toFixed(0);
}Determines the orientation of the Histogram widget.
Possible Values:"vertical" |"horizontal"
Default Value:"horizontal"
Example
histogram.layout = "vertical";The maximum value or bound of the entire histogram. This should match the maximum bound of the last bin.
Examples
histogram.max = 100;// sets result returned from a smart mapping method
// to the histogram
histogram.max = response.statistics.max;The minimum value or bound of the entire histogram. This should match the minimum bound of the first bin.
Examples
histogram.min = 0;// sets result returned from a smart mapping method
// to the histogram
histogram.min = response.statistics.min; state Stringreadonly
The state of the widget.
Possible Values:"ready" |"disabled"
The view model for the Histogram widget. This is a class that contains all the logic (properties and methods) that controls this widget's behavior. See the HistogramViewModel class to access all properties and methods on the Histogram widget.
Inherited
Property visible Boolean
Indicates whether the widget is visible.
If false, the widget will no longer be rendered in the web document. This may affect the layout of other elements or widgets in the document. For example, if this widget is the first of three widgets associated to the upper right hand corner of the view UI, then the other widgets will reposition when this widget is made invisible. For more information, refer to the css display value of "none".
Example
// Hides the widget in the view
widget.visible = false;Show inherited methods Hide inherited methods
Method DetailsInherited
Method addHandles(handleOrHandles, groupKey)
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, addHandles added at 4.25.
Adds one or more handles which are to be tied to the lifecycle of the object. The handles will be removed when the object is destroyed.
// Manually manage handles
const handle = reactiveUtils.when(
() => !view.updating,
() => {
wkidSelect.disabled = false;
},
{ once: true }
);
this.addHandles(handle);
// Destroy the object
this.destroy();
Parameters
Handles marked for removal once the object is destroyed.
groupKey *
optionalKey identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group.
Inherited
Method classes(classNames){String}
A utility method used for building the value for a widget's class property. This aids in simplifying css class setup.
Returns
Type Description String The computed class name.Example
// .tsx syntax showing how to set css classes while rendering the widget
render() {
const dynamicClasses = {
[css.flip]: this.flip,
[css.primary]: this.primary
};
return (
<div class={classes(css.root, css.mixin, dynamicClasses)} />
);
}Inherited
Method destroy()
Destroys the widget instance.
Inherited
Method emit(type, event){Boolean}
Emits an event on the instance. This method should only be used when creating subclasses of this class.
Parameters
The name of the event.
optionalThe event payload.
Returns
Type Description Booleantrue if a listener was notified
fromHistogramResult(result){Histogram}static
A convenience function used to create a Histogram widget instance from the result of the histogram statistics function.
Parameter
The result of the histogram statistics function used to generate a histogram for a field or expression from a layer.
Returns
Type Description Histogram The histogram instance representing the histogram returned from histogram.Example
let colorParams = {
layer: povLayer,
basemap: map.basemap,
field: "POP_POVERTY",
normalizationField: "TOTPOP_CY",
theme: "above-and-below"
};
let stats = null;
colorRendererCreator
.createContinuousRenderer(colorParams)
.then(function(response) {
// set the renderer to the layer and add it to the map
stats = response.statistics;
return histogram({
layer: povLayer,
field: "POP_POVERTY",
normalizationField: "TOTPOP_CY",
numBins: 100
});
})
.then(function(histogramResult) {
let histogram = Histogram.fromHistogramResult(histogramResult);
histogram.container = "histogram";
histogram.average = stats.avg;
})
.catch(function(error) {
console.log("there was an error: ", error);
});Inherited
Method hasEventListener(type){Boolean}
Indicates whether there is an event listener on the instance that matches the provided event name.
Returns
Type Description Boolean Returns true if the class supports the input event.Inherited
Method hasHandles(groupKey){Boolean}
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, hasHandles added at 4.25.
Returns true if a named group of handles exist.
Parameter
groupKey *
optionalA group key.
Returns
Type Description Boolean Returnstrue if a named group of handles exist.
Example
// Remove a named group of handles if they exist.
if (obj.hasHandles("watch-view-updates")) {
obj.removeHandles("watch-view-updates");
}Inherited
Method isFulfilled(){Boolean}
Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isFulfilled added at 4.19.
isFulfilled() may be used to verify if creating an instance of the class is fulfilled (either resolved or rejected). If it is fulfilled, true will be returned.
Returns
Type Description Boolean Indicates whether creating an instance of the class has been fulfilled (either resolved or rejected).Inherited
Method isRejected(){Boolean}
Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isRejected added at 4.19.
isRejected() may be used to verify if creating an instance of the class is rejected. If it is rejected, true will be returned.
Returns
Type Description Boolean Indicates whether creating an instance of the class has been rejected.Inherited
Method isResolved(){Boolean}
Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, isResolved added at 4.19.
isResolved() may be used to verify if creating an instance of the class is resolved. If it is resolved, true will be returned.
Returns
Type Description Boolean Indicates whether creating an instance of the class has been resolved.Inherited
Method on(type, listener){Object}
Registers an event handler on the instance. Call this method to hook an event with a listener.
Returns
Type Description Object Returns an event handler with aremove() method that should be called to stop listening for the event(s). Property Type Description remove Function When called, removes the listener from the event.
Example
view.on("click", function(event){
// event is the event handle returned after the event fires.
console.log(event.mapPoint);
});Inherited
Method postInitialize()
Executes after widget is ready for rendering.
Inherited
Method removeHandles(groupKey)
Since: ArcGIS Maps SDK for JavaScript 4.25 Accessor since 4.0, removeHandles added at 4.25.
Removes a group of handles owned by the object.
Parameter
groupKey *
optionalA group key or an array or collection of group keys to remove.
Example
obj.removeHandles(); // removes handles from default group
obj.removeHandles("handle-group");
obj.removeHandles("other-handle-group");Inherited
Method render(){Object}
This method is implemented by subclasses for rendering.
Returns
Type Description Object The rendered virtual node.Inherited
Method renderNow()
Renders widget to the DOM immediately.
Inherited
Method scheduleRender()
Schedules widget rendering. This method is useful for changes affecting the UI.
Inherited
Method when(callback, errback){Promise}
Since: ArcGIS Maps SDK for JavaScript 4.19 Widget since 4.2, when added at 4.19.
when() may be leveraged once an instance of the class is created. This method takes two input parameters: a callback function and an errback function. The callback executes when the instance of the class loads. The errback executes if the instance of the class fails to load.
Parameters
optionalThe function to call when the promise resolves.
optionalThe function to execute when the promise fails.
Returns
Type Description Promise Returns a new Promise for the result ofcallback.
Example
// Although this example uses the BasemapGallery widget, any class instance that is a promise may use when() in the same way
let bmGallery = new BasemapGallery();
bmGallery.when(function(){
// This function will execute once the promise is resolved
}, function(error){
// This function will execute if the promise is rejected due to an error
}); BarCreatedFunction(index, element)
Function used to style or attach custom interaction to histogram bars. This function should be set to the barCreatedFunction property. It fires for each bar when it is created.
Parameters
The index of the histogram bar. This directly corresponds to the index of the associated bin.
The histogram bar element to style.
Represents the bin of a histogram. A bin consists of a minimum and a maximum value and a count. It indicates the number of values in a dataset that lie between the min and max values.
The number of values in a dataset that are contained between the indicated minValue and maxValue.
The minimum value (or bound) of the bin.
The maximum value (or bound) of the bin.
DataLineCreatedFunction(lineElement, labelElement, index)
Function used to style dataLines. This function should be set to the dataLineCreatedFunction property. It fires when each data line is created.
Parameters
The SVG element representing the data line rendered on the histogram.
optionalThe SVG element representing the label rendered on the histogram for the associated line element.
optionalThe index of the data line.
LabelFormatter(value, type, index){String}
Function used to format labels. This function should be set to the labelFormatFunction property. This function fires every time a label is created or updated on the histogram.
Parameters
The value for the line on the data axis.
optionalThe label type. Currently, the only supported type is average.
The index of the data line (or value).
Returns
Type Description String The formatted value of the label.RetroSearch is an open source project built by @garambo | Open a GitHub Issue
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