Synthèse
Histograms visually summarize the distribution of a continuous numeric variable by measuring the frequency at which certain values appear in the dataset.
Discussion
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.
Syntaxe
Histogram (x, {splitCategory}, {miniChartsPerRow}, {showPreviewChart}, {binCount}, {showMean}, {showMedian}, {showStandardDeviation}, {showComparisonDistribution}, {dataTransformationType}, {dataTransformationParameters}, {title}, {description}, {xTitle}, {yTitle}, {dataSource}, {displaySize})| Paramètre | Explication | Type de données |
x | The field name for the x-axis variable. The field must be a numeric field. | String |
splitCategory | A categorical field that adds a separate series for each unique value in the field. | String |
miniChartsPerRow | The number of minicharts that will be shown per row. The number of rows will be determined by the total number of series divided by the miniChartsPerRow value. | Integer |
showPreviewChart | Specifies whether the preview chart will be displayed for grid charts.
(La valeur par défaut est False) | Boolean |
binCount | The number of bins to display in the histogram. | Integer |
showMean | Specifies whether the mean statistical line is visible in the histogram.
| Boolean |
showMedian | Specifies whether the median statistical line is visible in the histogram.
| Boolean |
showStandardDeviation | Specifies whether the standard deviation lines are visible in the histogram.
| Boolean |
showComparisonDistribution | Specifies whether the normal distribution comparison line is visible in the histogram.
| Boolean |
dataTransformationType | Specifies the data transformation type.
| String |
dataTransformationParameters | The data transformation parameters for the Box-Cox transformation. This parameter accepts a two-item list in which 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:
| 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 |
Propriétés
| Propriété | Explication | Type de données |
| binCount (Lecture et écriture) | The number of bins to display in the histogram. | Integer |
| dataSource (Lecture et écriture) | 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:
| Object |
| dataTransformationType (Lecture et écriture) | Specifies the data transformation type.
| String |
| description (Lecture et écriture) | The description of the chart. The description text appears at the bottom of the chart view. | String |
| displaySize (Lecture et écriture) | 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 (Lecture et écriture) | The properties of the chart legend.
| Object |
| miniChartsPerRow (Lecture et écriture) | The number of minicharts that will be shown per row. The number of rows will be determined by the total number of series divided by the miniChartsPerRow value. | Integer |
| showComparisonDistribution (Lecture et écriture) | Specifies whether the normal distribution comparison line is visible in the histogram.
| Boolean |
| showMean (Lecture et écriture) | Specifies whether the mean statistical line is visible in the histogram.
| Boolean |
| showMedian (Lecture et écriture) | Specifies whether the median statistical line is visible in the histogram.
| Boolean |
| showPreviewChart (Lecture et écriture) | Specifies whether the preview chart will be displayed for grid charts.
| Boolean |
| showStandardDeviation (Lecture et écriture) | Specifies whether the standard deviation lines are visible in the histogram.
| Boolean |
| splitCategory (Lecture et écriture) | A categorical field that adds a separate series for each unique value in the field. | String |
| theme (Lecture et écriture) | Specifies the name of the theme that is applied to the chart. | String |
| title (Lecture et écriture) | 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 (Lecture seule) | The string value indicating the chart type. | String |
| x (Lecture et écriture) | The field name for the x-axis variable. The field must be a numeric field. | String |
| xAxis (Lecture et écriture) | Sets the properties of the x-axis;
| Object |
| yAxis (Lecture et écriture) | Sets the properties of the y-axis:
| Object |
.Vue d’ensemble des méthodes
| Méthode | Explication |
| 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. |
Méthodes
addToLayer (layer_or_layerfile)
| Paramètre | Explication | Type de données |
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
chart.addToLayer(censusLayer)exportToSVG (path, width, height)
| Paramètre | Explication | Type de données |
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.
chart.addToLayer(myLayer)
# Further modification is necessary
chart.description = "Data from the U.S. Census Bureau"
chart.updateChart()Exemple de code
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)Vous avez un commentaire à formuler concernant cette rubrique ?