gvisLineChart: Google Line Chart with R

In jburos/GoogleVis: Interface between R and the Google Chart Tools

Description

The gvisLineChart function reads a data.frame and creates text output referring to the Google Visualisation API, which can be included into a web page, or as a stand-alone page. The actual chart is rendered by the web browser using SVG or VML.

Usage

gvisLineChart(data, xvar = "", yvar = "", options = list(), chartid)

Arguments

data	a data.frame to be displayed as a line chart
xvar	name of the character column which contains the category labels for the x-axes.
yvar	a vector of column names of the numerical variables to be plotted. Each column is displayed as a separate line.
options	list of configuration options for Google Line Chart. gvis.editor a character label for an on-page button which opens an in-page dialog box that enables users to edit, change and customise the chart. By default no value is given and therefore no button is displayed. Further possible components are, taken from https://google-developers.appspot.com/chart/interactive/docs/gallery/linechart.html#Configuration_Options: axisTitlesPosition a string. Default 'out'. Where to place the axis titles, compared to the chart area. Supported values: 'in' Draw the axis titles inside the the chart area. 'out' Draw the axis titles outside the chart area. 'none' Omit the axis titles. backgroundColor a string or object. Default 'white'. The background color for the main area of the chart. Can be either a simple HTML color string, for example: 'red' or '#00cc00', or an object with the following properties. backgroundColor.stroke a string. Default '#666'. The color of the chart border, as an HTML color string. backgroundColor.strokeWidth a number. Default 0. The border width, in pixels. backgroundColor.fill a string. Default 'white'. The chart fill color, as an HTML color string. chartArea a string. Default 'null'. An object with members to configure the placement and size of the chart area (where the chart itself is drawn, excluding axis and legends). Two formats are supported: a number, or a number followed by %. A simple number is a value in pixels; a number followed by % is a percentage. Example: {left:20,top:0,width:\"50%\",height:\"75%\"} chartArea.left a number or string. Default auto. How far to draw the chart from the left border. chartArea.top a number or string. Default auto. How far to draw the chart from the top border. chartArea.width a number or string. Default auto. Chart area width. chartArea.height a number or string. Default auto. Chart area height. colors An array of strings. Default 'colors'. The colors to use for the chart elements. An array of strings, where each element is an HTML color string, for example: colors:['red','#004411']. curveType a string. Default 'none'. Controls the curve of the lines. Can be one of the following: 'none' Straight lines without curve. 'function' The angles of the line will be smoothed. enableInteractivity boolean. Default TRUE. Whether the chart throws user-based events or reacts to user interaction. If false, the chart will not throw 'select' or other interaction-based events (but will throw ready or error events), and will not display hovertext or otherwise change depending on user input. focusTarget a string. Default 'datum' . The type of the entity that receives focus on mouse hover. Also affects which entity is selected by mouse click, and which data table element is associated with events. Can be one of the following: 'datum' Focus on a single data point. Correlates to a cell in the data. 'category' Focus on a grouping of all data points along the major axis. Correlates to a row in the data table. In focusTarget 'category' the tooltip displays all the category values. This may be useful for comparing values of different series. fontSize a number. Default automatic. The default font size, in pixels, of all text in the chart. You can override this using properties for specific chart elements. fontName a string. Default 'Arial'. The default font face for all text in the chart. You can override this using properties for specific chart elements. hAxis a JSON object. Default 'null'. An object with members to configure various horizontal axis elements. To specify properties of this object, you can use object literal notation, as shown here: {title: 'Hello', titleTextStyle: {color: '#FF0000'}} hAxis.baseline a number. Default automatic. The baseline for the horizontal axis. This option is only supported for a continuous axis. hAxis.baselineColor a string. Default 'black'. The color of the baseline for the horizontal axis. Can be any HTML color string, for example: 'red' or '#00cc00'. This option is only supported for a continuous axis. hAxis.direction 1 or -1. Default 1. The direction in which the values along the vertical axis grow. Specify -1 to reverse the order of the values. hAxis.format a string. Default auto. A format string for numeric or date axis labels. For number axis labels, this is a subset of the decimal formatting ICU pattern set. For instance, {format:'#,###%'}. will display values \code"1,000%", "750%", and "50%" for values 10, 7.5, and 0.5. For date axis labels, this is a subset of the date formatting ICU pattern set. For instance, {format:'MMM d, y'}. will display the value "Jul 1, 2011" for the date of July first in 2011. The actual formatting applied to the label is derived from the locale the API has been loaded with. For more details, see loading charts with a specific locale. This option is only supported for a continuous axis. hAxis.gridlines a JSON object. Default null. An object with members to configure the gridlines on the horizontal axis. To specify properties of this object, you can use object literal notation, as shown here: {color: '#333', count: 4} This option is only supported for a continuous axis. hAxis.gridlines.color a string. Default '#CCC'. The color of the vertical gridlines inside the chart area. Specify a valid HTML color string. hAxis.gridlines.count a number. Default 5.The number of vertical gridlines inside the chart area. Minimum value is 2. hAxis.logScale boolean. Default FALSE. vAxis property that makes the vertical axis a logarithmic scale (requires all values to be positive). Set to TRUE for yes. This option is only supported for a continuous axis. hAxis.textPosition a string. Default 'out' Position of the horizontal axis text, relative to the chart area. Supported values: 'out', 'in', 'none'. hAxis.textStyle a JSON object. Default {color: 'black', fontName: <global-font-name>, fontSize: <global-font-size>} An object that specifies the horizontal axis text style. The object has this format: {color: <string>, fontName: <string>, fontSize: <number>} The color can be any HTML color string, for example: 'red' or '#00cc00'. Also see fontName and fontSize. hAxis.title a string. Default 'null'. hAxis property that specifies the title of the horizontal axis. hAxis.titleTextStyle a JSON object. Default {color: 'black', fontName: <global-font-name>, fontSize: <global-font-size>}. An object that specifies the horizontal axis title text style. The object has this format: {color: <string>, fontName: <string>, fontSize: <number>} The color can be any HTML color string, for example: 'red' or '#00cc00'. Also see fontName and fontSize. hAxis.slantedText boolean. Default automatic. If true, draw the horizontal axis text at an angle, to help fit more text along the axis; if false, draw horizontal axis text upright. Default behavior is to slant text if it cannot all fit when drawn upright. Notice that this option is available only when the hAxis.textPosition is set to 'out' (which is the default). This option is only supported for a discrete axis. hAxis.slantedTextAngle a number, 1-90. Default 30. The angle of the horizontal axis text, if it's drawn slanted. Ignored if hAxis.slantedText is false, or is in auto mode, and the chart decided to draw the text horizontally. This option is only supported for a discrete axis. hAxis.maxAlternation a number. Default 2. Maximum number of levels of horizontal axis text. If axis text labels become too crowded, the server might shift neighboring labels up or down in order to fit labels closer together. This value specifies the most number of levels to use; the server can use fewer levels, if labels can fit without overlapping. This option is only supported for a discrete axis. hAxis.showTextEvery a number. Default automatic. How many horizontal axis labels to show, where 1 means show every label, 2 means show every other label, and so on. Default is to try to show as many labels as possible without overlapping. This option is only supported for a discrete axis. hAxis.maxValue a number. Default automatic. hAxis property that specifies the highest vertical axis grid line. The actual grid line will be the greater of two values: the maxValue option value, or the highest data value, rounded up to the next higher grid mark. This option is only supported for a continuous axis. hAxis.minValue a number. Default automatic. hAxis property that specifies the lowest vertical axis grid line. The actual grid line will be the lower of two values: the minValue option value, or the lowest data value, rounded down to the next lower grid mark. This option is only supported for a continuous axis. hAxis.viewWindowMode a string. Default "pretty" if hAxis.viewWindow is null, "explicit" otherwise. Specifies how to scale the horizontal axis to render the values within the chart area. The following string values are supported: 'pretty' Scale the horizontal values so that the maximum and minimum data values are rendered a bit inside the left and right of the chart area. 'maximized' Scale the horizontal values so that the maximum and minimum data values touch the left and right of the chart area. 'explicit' Specify the left and right scale values of the chart area. Data values outside these values will be cropped. You must specify a hAxis.viewWindow object describing the maximum and minimum values to show. This option is only supported for a continuous axis. hAxis.viewWindow Object. Default NULL. Specifies the cropping range of the horizontal axis. hAxis.viewWindow.max A number. Default auto. For a continuous axis The maximum horizontal data value to render. Has an effect only if hAxis.viewWindowMode='explicit'. For a discrete axis The zero-based row index where the cropping window ends. Data points at this index and higher will be cropped out. In conjunction with vAxis.viewWindowMode.min, it defines a half-opened range [min, max) that denotes the element indices to display. In other words, every index such that min <= index < max will be displayed. hAxis.viewWindow.min A number. Default auto. For a continuous axis The minimum horizontal data value to render. Has an effect only if hAxis.viewWindowMode='explicit'. For a discrete axis The zero-based row index where the cropping window begins. Data points at indices lower than this will be cropped out. In conjunction with vAxis.viewWindowMode.max, it defines a half-opened range [min, max) that denotes the element indices to display. In other words, every index such that min <= index < max will be displayed. height a number. Default height of the containing element. Height of the chart, in pixels. interpolateNulls boolean. Default FALSE. Whether to guess the value of missing points. If true, it will guess the value of any missing data based on neighbouring points. If false, it will leave a break in the line at the unknown point. legend a JSON object. Default NULL. An object with members to configure various aspects of the legend. To specify properties of this object, you can use object literal notation, as shown here: {position: 'top', textStyle: {color: 'blue', fontSize: 16}} legend.position a string. Default 'right'. Position of the legend. Can be one of the following: 'right' To the right of the chart. 'top' Above the chart. 'bottom' Below the chart. 'none' No legend is displayed. legend.textStyle a JSON object. Default {color: 'black', fontName: <global-font-name>, fontSize: <global-font-size>} An object that specifies the legend text style. The object has this format: {color: <string>, fontName: <string>, fontSize: <number>} The color can be any HTML color string, for example: 'red' or '#00cc00'. Also see fontName and fontSize. lineWidth a number. Default 2. Line width in pixels. Use zero to hide all lines and show only the points. pointSize a number. Default 0. Diameter of data points, in pixels. Use zero to hide all points. reverseCategories boolean. Default FALSE. If set to true, will draw series from right to left. The default is to draw left-to-right. series a JSON array of objects, or object with nested objects. Default {}. An array of objects, each describing the format of the corresponding series in the chart. To use default values for a series, specify an empty object . If a series or a value is not specified, the global value will be used. Each object supports the following properties: color The color to use for this series. Specify a valid HTML color string. targetAxisIndex Which axis to assign this series to, where 0 is the default axis, and 1 is the opposite axis. Default value is 0; set to 1 to define a chart where different series are rendered against different axes. You can define a different scale for different axes. pointSize Overrides the global pointSize value for this series. lineWidth Overrides the global lineWidth value for this series. curveType Overrides the global curveType value for this series. visibleInLegend A boolean value, where true means that the series should have a legend entry, and false means that it should not. Default is TRUE. You can specify either an array of objects, each of which applies to the series in the order given, or you can specify an object where each child has a numeric key indicating which series it applies to. For example, the following two declarations are identical, and declare the first series as black and absent from the legend, and the fourth as red and absent from the legend: series: [{color: 'black', visibleInLegend: false},{}, {}, {color: 'red', visibleInLegend: false}] series: {0:{color: 'black', visibleInLegend: false}, 3:{color: 'red', visibleInLegend: false}} theme a string. Default NULL. A theme is a set of predefined option values that work together to achieve a specific chart behavior or visual effect. Currently only one theme is available: maximized Maximizes the area of the chart, and draws the legend and all of the labels inside the chart area. Sets the following options: chartArea: {width: '100%', height: '100%'}, legend: {position: 'in'}, titlePosition: 'in', axisTitlesPosition: 'in', hAxis: {textPosition: 'in'}, vAxis: {textPosition: 'in'} title a string. Default no title. Text to display above the chart. titlePosition a string. Default 'out'. Where to place the chart title, compared to the chart area. Supported values: 'in' Draw the title inside the chart area. 'out' Draw the title outside the chart area. 'none' Omit the title. titleTextStyle a JSON object. Default {color:'black', fontName:<global-font-name>,fontSize:<global-font-size>}. An object that specifies the title text style. The object has this format: {color: <string>, fontName: <string>, fontSize: <number>} The color can be any HTML color string, for example: 'red' or '#00cc00'. Also see fontName and fontSize. tooltip a JSON object. Default NULL. An object with members to configure various tooltip elements. To specify properties of this object, you can use object literal notation, as shown here: {textStyle: {color: '#FF0000'}, showColorCode: true} tooltip.showColorCode boolean. Default automatic. If true, show colored squares next to the series information in the tooltip. The default is true when focusTarget is set to 'category', otherwise the default is FALSE. tooltip.TextStyle a JSON object. Default {color: 'black', fontName: <global-font-name>, fontSize: <global-font-size>} An object that specifies the tooltip text style. The object has this format: {color: <string>, fontName: <string>, fontSize: <number>} The color can be any HTML color string, for example: 'red' or '#00cc00'. Also see fontName and fontSize. tooltip.trigger The user interaction that causes the tooltip to be displayed: 'hover' The tooltip will be displayed when the user hovers over an element. 'none' The tooltip will not be displayed. vAxes a JSON array of objects, or object with child objects null. Specifies properties for individual vertical axes, if the chart has multiple vertical axes. Each child object is a vAxis object, and can contain all the properties supported by vAxis. These property values override any global settings for the same property. To specify a chart with multiple vertical axes, first define a new axis using series.targetAxisIndex, then configure the axis using vAxes. The following example assigns series 2 to the right axis and specifies a custom title and text style for it: series:{2:{targetAxisIndex:1}}, vAxes:{1:{title:'Losses',textStyle:{color: 'red'}}} This property can be either an object or an array: the object is a collection of objects, each with a numeric label that specifies the axis that it defines–this is the format shown above; the array is an array of objects, one per axis. For example, the following array-style notation is identical to the vAxis object shown above: vAxes:[ {}, // Nothing specified for axis 0 {title:'Losses',textStyle:{color: 'red'}} // Axis 1 ] vAxis a JSON object. Default 'null'. An object with members to configure various vertical axis elements. To specify properties of this object, you can use object literal notation, as shown here: {title: 'Hello', titleTextStyle: {color: '#FF0000'}} vAxis.baseline a number. Default automatic. vAxis property that specifies the baseline for the vertical axis. If the baseline is smaller than the highest grid line or smaller than the lowest grid line, it will be rounded tothe closest gridline. vAxis.baselineColor a string. Default 'black'. vAxis property that specifies the color of the baseline for the vertical axis. Can be any HTML color string, for example: 'red' or '#00cc00'. vAxis.direction 1 or -1. Default 1. The direction in which the values along the vertical axis grow. Specify -1 to reverse the order of the values. vAxis.format a string. Default auto. A format string for numeric axis labels. This is a subset of the ICU pattern set. For instance, {format:'#,###%'}. will display values 1,000%, 750%, and 50% for values 10, 7.5, and 0.5. vAxis.gridlines a JSON object. Default NULL. An object with members to configure the gridlines on the vertical axis. To specify properties of this object, you can use object literal notation, as shown here: {color: '#333', count: 4} vAxis.gridlines.color a string. Default '#CCC'. The color of the vertical gridlines inside the chart area. Specify a valid HTML color string. vAxis.gridlines.count a number. Default 5.The number of vertical gridlines inside the chart area. Minimum value is 2. vAxis.logScale boolean. Default FALSE. vAxis property that makes the vertical axis a logarithmic scale (requires all values to be positive). Set to TRUE for yes. vAxis.textPosition a string. Default 'out'. Position of the vertical axis text, relative to the chart area. Supported values: 'out', 'in', 'none'. vAxis.textStyle a JSON object. Default {color: 'black', fontName: <global-font-name>, fontSize: <global-font-size>}. An object that specifies the vertical axis text style. The object has this format: {color: <string>, fontName: <string>, fontSize: <number>} The color can be any HTML color string, for example: 'red' or '#00cc00'. Also see fontName and fontSize. vAxis.title a string. Default no title. vAxis property that specifies a title for the vertical axis. vAxis.titleTextStyle a JSON object. Default {color: 'black', fontName: <global-font-name>, fontSize: <global-font-size>}. An object that specifies the vertical axis title text style. The object has this format: {color: <string>, fontName: <string>, fontSize: <number>} The color can be any HTML color string, for example: 'red' or '#00cc00'. Also see fontName and fontSize. vAxis.maxValue a number. Default automatic. vAxis property that specifies the highest vertical axis grid line. The actual grid line will be the greater of two values: the maxValue option value, or the highest data value, rounded up to the next higher grid mark. vAxis.minValue a number. Default automatic. vAxis property that specifies the lowest vertical axis grid line. The actual grid line will be the lower of two values: the minValue option value, or the lowest data value, rounded down to the next lower grid mark. vAxis.viewWindowMode a string. Default "pretty" if vAxis.viewWindow is null, "explicit" otherwise. Specifies how to scale the vertical axis to render the values within the chart area. The following string values are supported: 'pretty' Scale the vertical values so that the maximum and minimum data values are rendered a bit inside the top and bottom of the chart area. 'maximized' Scale the vertical values so that the maximum and minimum data values touch the top and bottom of the chart area. 'explicit' Specify the top and bottom scale values of the chart area. Data values outside these values will be cropped. You must specify a vAxis.viewWindow object describing the maximum and minimum values to show. vAxis.viewWindow Object. Default NULL. Specifies the maximum and minimum data values to show on the vertical axis. Present only if vAxis.viewWindowMode='explicit' vAxis.viewWindow.max A number. Default 0. The maximum vertical data value to render. vAxis.viewWindow.min A number. Default 0. The minimum vertical data value to render. width a number. Default width of the containing element. Width of the chart, in pixels.
chartid	character. If missing (default) a random chart id will be generated based on chart type and tempfile

Value

gvisLineChart returns list of class "gvis" and "list".

An object of class "gvis" is a list containing at least the following components:

type	Google visualisation type, here 'LineChart'
chartid	character id of the chart object. Unique chart ids are required to place several charts on the same page.
html	a list with the building blocks for a page header a character string of a html page header: <html>...<body>, chart a named character vector of the chart's building blocks: jsHeader Opening <script> tag and reference to Google's JavaScript library. jsData JavaScript function defining the input data as a JSON object. jsDrawChart JavaScript function combing the data with the visualisation API and user options. jsDisplayChart JavaScript function calling the handler to display the chart. jsFooter End tag </script>. jsChart Call of the jsDisplayChart function. divChart <div> container to embed the chart into the page. caption character string of a standard caption, including data name and chart id. footer character string of a html page footer: </body>...</html>, including the used R and googleVis version and link to Google's Terms of Use.

Warning

Google Visualisation API: You cannot load both linechart and corechart packages at the same time on the same page.

Author(s)

Markus Gesmann [e-mail],

Diego de Castillo [e-mail]

References

Google Line Chart API: http://code.google.com/apis/chart/interactive/docs/gallery/linechart.html

Follow the link for Google's data policy.

See Also

See also print.gvis, plot.gvis for printing and plotting methods

Examples

## Please note that by default the googleVis plot command
## will open a browser window and requires an internet
## connection to display the visualisation.

df <- data.frame(country=c("US", "GB", "BR"), val1=c(1,3,4), val2=c(23,12,32))

## Line chart
Line1 <- gvisLineChart(df, xvar="country", yvar=c("val1", "val2"))
plot(Line1)


## Add a customised title and smoothed curve
Line2 <- gvisLineChart(df, xvar="country", yvar=c("val1", "val2"),
             options=list(title="Hello World",
                          titleTextStyle="{color:'red',fontName:'Courier',fontSize:16}",
                          curveType='function'))
plot(Line2)

## Not run: 
## Change y-axis to percentages
Line3 <- gvisLineChart(df, xvar="country", yvar=c("val1", "val2"),
                       options=list(vAxis="{format:'#,###%'}"))
plot(Line3)


## End(Not run)

## Create a chart with two y-axis:
Line4 <-  gvisLineChart(df, "country", c("val1","val2"),
                        options=list(series="[{targetAxisIndex: 0},
                                              {targetAxisIndex:1}]",
                          vAxes="[{title:'val1'}, {title:'val2'}]"
                          ))
plot(Line4)

## Line chart with edit button
Line5 <- gvisLineChart(df, xvar="country", yvar=c("val1", "val2"),
                       options=list(gvis.editor="Edit me!"))
plot(Line5)

jburos/GoogleVis documentation built on May 18, 2019, 9:19 p.m.