# Histogram

## Zusammenfassung

Histograms visually summarize the distribution of a continuous numeric variable by measuring the frequency at which certain values appear in the dataset.

## Diskussion

When creating a chart object, optional arguments for the class constructor must be specified using the argument name; they cannot be specified by argument position. See the Code Samples section for an example of how to specify arguments using keywords.

## Syntax

`Histogram (x, {binCount}, {showMean}, {showMedian}, {showStandardDeviation}, {showComparisonDistribution}, {dataTransformationType}, {dataTransformationParameters}, {title}, {description}, {xTitle}, {yTitle}, {dataSource}, {displaySize})`
 Parameter Erläuterung Datentyp x The field name for the x-axis variable. The field must be a numeric field. String binCount The number of bins to display in the histogram. Integer showMean Indicates whether the mean statistical line is visible in the histogram.True—Displays the mean line.False—Hides the mean line. Boolean showMedian Indicates whether the median statistical line is visible in the histogram.True—Displays the median line.False—Hides the median line. Boolean showStandardDeviation Indicates whether the standard deviation lines are visible in the histogram.True—Displays the standard deviation lines.False—Hides the standard deviation lines. Boolean showComparisonDistribution Indicates whether the normal distribution comparison line is visible in the histogram.True—Displays the comparison line.False—Hides the comparison line. Boolean dataTransformationType The data transformation type.none—No transformation is applied.logarithmic—A logarithmic transformation is applied.squareRoot—A square root transformation is applied.inverse—An inverse transformation is applied.boxCox—A box-cox transformation is applied. String dataTransformationParameters The data transformation parameters for the Box-Cox transformation. This parameter accepts a two-item list where the first item is the power parameter and the second item is the shift parameter. List title The title of the chart. The title text appears at the top of the chart view and is used as the label for the chart in the Contents pane. String description The description of the chart. The description text appears at the bottom of the chart view. String xTitle The title of the x-axis of the chart. String yTitle The title of the y-axis of the chart. String dataSource The data source of the chart. When a chart is exported using the exportToSVG method or displayed in an ArcGIS Notebook, the data source will be read and rendered on the chart. Valid data sources include the following:Paths to datasets, including local datasets, UNC paths, and service URLsArrow table objectsLayer objects Object displaySize[displaySize,...] The size of the chart when exported using the exportToSVG method or displayed in an ArcGIS Notebook. The value must be specified as a two-item list in which the first item is the width of the chart and the second item is the height of the chart. List

## Eigenschaften

 Eigenschaft Erläuterung Datentyp binCount(Lesen und schreiben) The number of bins to display in the histogram. Integer dataSource(Lesen und schreiben) The data source of the chart. When a chart is exported using the exportToSVG method or displayed in an ArcGIS Notebook, the data source will be read and rendered on the chart. Valid data sources include the following:Paths to datasets, including local datasets, UNC paths, and service URLsArrow table objectsLayer objects. Object dataTransformationType(Lesen und schreiben) The data transformation type.none—No transformation is applied.logarithmic—A logarithmic transformation is applied.squareRoot—A square root transformation is applied.inverse—An inverse transformation is applied.boxCox—A box-cox transformation is applied. String description(Lesen und schreiben) The description of the chart. The description text appears at the bottom of the chart view. String displaySize(Lesen und schreiben) The size of the chart when exported using the exportToSVG method or displayed in an ArcGIS Notebook. The value must be specified as a two-item list in which the first item is the width of the chart and the second item is the height of the chart. List legend(Lesen und schreiben) The properties of the chart legend.visible—Specifies whether the legend will be displayed in the chart view. True displays the legend, and False hides the legend.title—The title of the legend. Object showComparisonDistribution(Lesen und schreiben) Indicates whether the normal distribution comparison line is visible in the histogram.True—Displays the comparison line.False—Hides the comparison line. Boolean showMean(Lesen und schreiben) Indicates whether the mean statistical line is visible in the histogram.True—Displays the mean line.False—Hides the mean line. Boolean showMedian(Lesen und schreiben) Indicates whether the median statistical line is visible in the histogram.True—Displays the median line.False—Hides the median line. Boolean showStandardDeviation(Lesen und schreiben) Indicates whether the standard deviation lines are visible in the histogram.True—Displays the standard deviation lines.False—Hides the standard deviation lines. Boolean theme(Lesen und schreiben) Specifies the name of the theme that is applied to the chart. String title(Lesen und schreiben) The title of the chart. The title text appears at the top of the chart view and is used as the label in the Contents pane on the List By Drawing Order tab . String type(Schreibgeschützt) The string value indicating the chart type. String x(Lesen und schreiben) The field name for the x-axis variable. The field must be a numeric field. String xAxis(Lesen und schreiben) Sets the properties of the x-axis.field—The field name for the x-axis variable. The field must be a numeric field. logarithmic—This property is not supported for the Histogram class.maximum—The maximum axis bound.minimum—The minimum axis bound. sort—This property is not supported for the Histogram class.title—The label of the axis that displays on the chart. Object yAxis(Lesen und schreiben) Sets the properties of the y-axis.field—This property is not supported for the Histogram class. logarithmic—This property is not supported for the Histogram class.maximum—The maximum axis bound. minimum—The minimum axis bound.sort—This property is not supported for the Histogram class.title—The label of the axis that displays on the chart. Object

## Methodenübersicht

 Methode Erläuterung addToLayer (layer_or_layerfile) Adds the chart object to a layer or stand-alone table. exportToSVG (path, width, height) Exports the chart to SVG format. updateChart () Updates chart properties to sync changes between the object and the chart previously added to a layer.

## Methoden

`addToLayer (layer_or_layerfile)`
 Parameter Erläuterung Datentyp layer_or_layerfile The chart will be added to the target object. The layer_or_layerfile argument can be a Layer or a Table object. Object

Often the final step after defining chart properties is to add the chart object to a layer or table using the addToLayer method.

Add a chart to an existing layer.

``````import arcpy

aprx = arcpy.mp.ArcGISProject("current")
map = aprx.listMaps()[0]
censusLayer = map.listLayers('Census Block Groups')[0]

# Add chart object to a layer
`exportToSVG (path, width, height)`
 Parameter Erläuterung Datentyp path The path where the chart will be exported in SVG format. String width The width of the output graphic. Integer height The height of the output graphic. Integer

In some cases, you may want to save the chart as a graphic that can be shared and viewed outside of ArcGIS Pro. Exporting to the SVG graphic format is beneficial, as the chart elements and text are stored as vector elements that can be independently modified in a vector graphics software. An SVG graphic can also be resized to any scale without pixelation or loss in quality.

Export a chart that has a project layer data source to an .svg file.

``````import arcpy

aprx = arcpy.mp.ArcGISProject('current')
censusLayer = aprx.listMaps()[0].listLayers('Census Block Groups')[0]

# Set data source of chart object to a layer within current project
chart.dataSource = censusLayer

# Save the chart to file with dimensions width=500, height=500
chart.exportToSVG('populationByState.svg', 500, 500)``````

Export a chart that has a feature service data source to an .svg file.

``````
featureServiceURL = r'https://services1.arcgis.com/hLJbHVT9ZrDIzK0I/arcgis/rest/services/CrimesChiTheft/FeatureServer/0'

# Set data source of chart object to a feature service URL
chart.dataSource = featureServiceURL

# Save the chart to file with dimensions width=800, height=600
chart.exportToSVG('theftsPerBeat.svg', 800, 600)``````
`updateChart ()`

Often the final step after defining chart properties is to add the chart object to a layer using the addToLayer method.

To further modify the chart properties, you can modify the properties of the original chart instead of starting from scratch with a new chart. You can then use the updateChart method to synchronize any changes into the chart that was added to the layer. This will allow the changes you make to be presented in the Chart properties pane and chart view.

Use the updateChart method to synchronize chart property changes into a layer.

``````

# Further modification is necessary
chart.description = "Data from the U.S. Census Bureau"
chart.updateChart()``````

## Codebeispiel

Create a histogram using a layer name as the data source and export the histogram to an .svg file.

``````
import arcpy
chart = arcpy.charts.Histogram("price", binCount=20, showMedian=True)
chart.dataSource = "airbnb_listings"
chart.title = "Distribution of AirBnB Listing Price"
chart.exportToSVG("histogram.svg", width=1000, height=800)``````