Altair mark text color For example, here is the difference between a May 16, 2018 · How would I adjust this to make each line a different color and create dashes only on the part of the line where the dummy variable is equal to one? Like how the bars are opaque for future values, I want to make the line dashed for future values. Arc marks are typically used for radial plots such as pie and donut charts. value(1),alt. Top Level Feb 14, 2023 · Pie Chart with Labels and facet in altair: not able to proper render the value labels The plot below uses an interval selection, which causes the chart to include an interactive brush (shown in grey). This tutorial will guide you through the process of creating visualizations in Altair. formatstr, dict, Dict, Format, TimeFormatSpecifier The text format specifier for formatting number and date/time in labels of guides (axes, legends, headers) and text marks. 5. Jun 22, 2018 · Contents Intro to Altair Building Interactive Altair Charts Sharing Interactive Altair Charts on the Web Resources Adding interactivity to data visualizations can be helpful for better exploring the data and fun. Matplotlib has been enormously successful at making Python viable as a standard language for scientific computing and data analysis. Jun 27, 2019 · I pass the color separately to the bars object while I create the mark_text on top of the base object (which knows nothing of the color). What's reputation and how do I get it? Instead, you can save this post to reference later. I've found this image online but it only has html code for vega-lite. Effect of Data Type on Axis Scales Similarly, for x and y axis encodings, the type used for the data will affect the scales used and the characteristics of the mark. The Data We're going to use the . encode” allows you to configure the plot specifics. For both the bar and text marks, we use the stack argument in the x encoding to cause the values to be stacked horizontally. Legends can be numeric, or category based. Sets mark color. CalculateTransform altair. Chart (source). Syntax: alt. 0f'). You can then use this encoding to build Vega-Lite - a high-level grammar for statistical graphics. Note the line from altair import datum. In this post I will show some examples of using the Altair library to create and share some simple Jan 8, 2022 · Altair mark_text position based on condition Asked 3 years, 7 months ago Modified 3 years, 6 months ago Viewed 3k times Simple Charts: Core Concepts The goal of this section is to teach you the core concepts required to create a basic Altair chart; namely: Data, Marks, and Encodings: the three core pieces of an Altair chart Encoding Types: Q (quantitative), N (nominal), O (ordinal), T (temporal), which drive the visual representation of the encodings Binning and Aggregation: which let you control aspects of the Multi-Line Tooltip # This example shows how you can use selections and layers to create a tooltip-like behavior tied to the x position of the cursor. Jul 19, 2025 · Altair is a declarative statistical visualization library in Python, designed to make it easy to create clear and informative graphics with minimal code. What would you like to happen instead? I would like the mark_text font/weight to appear the same as the axis labels. g. The Edit Legend dialog allows you to change the legend properties. Sep 17, 2020 · チャネルには x y color shape size などがある。 Altairはチャネルに渡すデータの型を自動で見てくれる。 以下の例では、 b が数値型だと自動で判別している。 Jul 16, 2022 · alt. You can edit the contour legend in the Edit Legend dialog, which is accessed by clicking Edit Legend on the Contour, Tensor, and Vector panels. If set to 0. By default, the size of bars on continuous scales will be set based on the In Altair, marks can be most conveniently specified by the mark_* methods of the Chart object, which take optional keyword arguments that are passed to MarkDef to configure the look of the marks. choose a color from a dropdown list, click plot, and add a new plot to the existing chart with the color chosen). bandfloat For rect-based marks ( rect, bar, and image ), mark size relative to bandwidth of band scales, bins or time units. Tukey Box Plot is the default box plot in Altair. labelFontSizedict, float, ExprRef Apr 10, 2019 · Is there any way to set the size of the points on a mark_line chart with the 'shape' encoding without overlaying a mark_line and a mark_point chart? st. That said, once you have a useful visualization, you will often want to adjust certain aspects of it. I would like to label each bar with the value of 'Time'. While line marks default to using straight line segments, different interpolation methods can be used to create smoothed or stepped paths. How can we do that such that the size is fixed, and the overall heatmap just gets bigger if we have more boxes to show? Mar 29, 2019 · I like Altair a lot for making graphs in Python. Additionally, some marks may have special mark properties (listed in their documentation page). Why Use Altair? Unlike imperative libraries such as matplotlib or seaborn, where you must specify Jul 23, 2025 · In Altair, you can customize the font size of axis labels by using the configure_axis method. X('index', title = '', axis = alt. Vega provides a collection of perceptually-motivated color schemes, many of which were originally created by Cynthia Brewer and the ColorBrewer project, or by Maureen Stone of Tableau Software. Or, from the Text menu, select Attributes. For both of these, I explicitly tell Altair they are Nominal types. read_ There's not any good automated way to do this, because text angles in Vega-Lite cannot be tied to data coordinates. Global Aug 23, 2023 · Image by Author Summary Congratulations! You have just learned three different ways to represent a percentage in Python Altair: Donut Chart through the mar_arc() mark method 100% Stacked Bar Chart Extending from @Philipp_Kats's answer and @dominik's comment (and for anyone else who stumbled upon this thread and wish to see the Altair code example), the current way of achieving a "tooltip" effect along the lines is to: Create the line (mark_line()) Create a selection that chooses the nearest point & selects based on x-value Snap some transparent selectors across the line, informing the x Vega-Lite - a high-level grammar for statistical graphics. This will ignore the color setting of the text layer. encode () Here is a simple example of how to create a bar chart using Altair: May 21, 2021 · You'll need to complete a few actions and gain 15 reputation points before being able to upvote. However, when dealing with negative values, this default positioning can lead to label overlap with the bar. mark_text (baseline="top") end_year = text. For example, the following uses mark_circle() with additional arguments to represent points as red semi-transparent filled circles: Learn how to annotate Altair charts in Streamlit with text, images, and emojis using layered charts for enhanced data visualization. encode(x='x:Q',opacity=alt. labelFontstr, dict, ExprRef The font of the legend label. Instead of matplotlib and seaborn, we are going to use the Python library altair. You can use a data encoding free from any color specification. Vega currently supports axes for Cartesian (rectangular) coordinates. Point marks are commonly used in visualizations like scatter plots. This means that if your source data contain (multi)lines, you will have to explicitly define the filled value as False. Is it possible to hide, remove or shrink opacity for this? Code is: import altair as al Whether the mark’s color should be used as fill color instead of stroke color. Sometimes it's quite simple, as in this example in the documentation. mark_bar(), etc - in altair. How can I directly tell altair to plot using a certain color? I tried: A rule mark definition can contain any standard mark properties. Arc # Arc marks are circular arcs defined by a center point plus angular and radial extents. configure_header() method. Jul 28, 2018 · Here's the chart I want to make. Chart Configuration Altair provides a number of hooks to configure the look of your chart; we don’t have time to go into all the available options here, but it is useful to know where and how such configuration settings can be accessed and explored. This is adapted from a corresponding Vega-Lite Example: Pie Chart. Use transform_filter() from datum to select the points (data subset) that needs the annotation. My original code, without the legend, looks like this: source = df line1 = alt. General Mark Properties Jun 4, 2020 · For this particular example, you could add a new line character to the label that needs the new line: 'a longer label that \nneeds a line break' and then change the parameters inside mark_text to include lineBreak=r'\n' Aug 28, 2022 · Multiline text in mark_text?thank you for your example. For a Tukey box plot, the whisker spans from May 11, 2018 · Adding “. Vega-Lite specifications consist of simple mappings of variables in a data set to visual encoding channels such as x, y, color, and size. encode(opacity=alt. Altair generally can Times & Dates # Working with dates, times, and timezones is often one of the more challenging aspects of data analysis. Y('sum(CARRIER_COUNT):Q', stack='zero'), detail='TERMS:N', text=alt. legend (None) ) text = base. Examples # Width/Height-Spanning Rules # If the rule mark only has y encoding, the output view produces horizontal rules that spans the complete width. Line marks are commonly used to depict trajectories or change over time. In Altair, the difficulties are compounded by the fact that users are writing Python code, which outputs JSON-serialized timestamps, which are interpreted by Javascript, and then rendered by your browser. Categorical altair. Jan 15, 2021 · measure_max_plot = alt. This method allows you to set various properties of the axis, including the font size, font family, and color of the axis labels. Color altair. Jun 20, 2017 · You can get annotations into your Altair plots in two steps: Use mark_text() to specify the annotation's position, fontsize etc. These mappings are then translated into detailed 2) field is not required if aggregate is count. Adding “. properties(width=700) Regarding the placement I tried different parameters of the MarkDef using the docs here but didn't find an option that allows placement relative to chart and not to bar. The issues are same as the question, are there any problems? order=alt. They are summarized in the following tables: A rect mark definition can contain any standard mark properties and the following special properties: Click to show table In Altair, marks can be most conveniently specified by the mark_* methods of the Chart object, which take optional keyword arguments that are passed to MarkDef to configure the look of the marks. Use the Legend entity to create, edit and assign custom legends to any contour, vector and tensor or marker plot. There are three possible approaches to these: “Global Config” acts on an entire chart object “Local Config” acts on one mark of the chart “Encoding” channels can also be used to set some chart properties Global Config # First, every chart type has a "config" property at the top level The . I think its an easy task for you so See also: aggregate documentation. But with a bit of tweaking you can accomplish this with a text layer: Axes Axes visualize spatial scale mappings using ticks, grid lines and labels. Feb 4, 2023 · Given the image below some values are smaller than 50. condition(nearest,alt. In general, there are two or three places where the look of a chart can be controlled, each with a greater priority than the last. General Mark Properties Suppose you wish to change the color of the points to red, and the opacity of the points to 20%. CompositeMarkDef altair Line # The line mark represents the data points stored in a field with a line connecting all of these points. Select a color from the color palette. Is there a way to: (1) Change the opacity of my text and (2) change the color of the same text. Here's my code: bar = alt. Vega is a visualization grammar, a declarative format for creating, saving, and sharing interactive visualization designs. (bars + text_sub_brand + text_cluster). We can use rules to show the average price of different stocks akin Stacked Bar Chart with Text Overlay # This example shows how to overlay text on a stacked bar chart. It can be copied or saved to an external file and imported for re-use. This is adapted from a corresponding Vega-Lite Example: Pie Chart with Labels. Figure 1. , Hi @jakevdp, i try adding order encoding but it still didn't work as expected. mark_circle(), . to Sep 26, 2018 · Hi, I was wondering how we can add text to stacked bar charts that have differing lengths. Is it possible to have text marks in the corresponding stack of a Nov 12, 2020 · I want to combine text and a calculated value in mark_text (). If set to 1, the mark size is set to the bandwidth, the bin interval, or the time unit interval. Header Configuration # Header configuration defines default settings for headers including the font, color, size, and position of the title and labels and can be set using the Chart. With Vega, you can describe the visual appearance and interactive behavior of a visualization in a JSON format, and generate web-based views using Canvas or SVG. Order ('color_Category_sort_index:Q'), Thanks you very much. Area marks are often used to show change over time, using either a single area or stacked areas. This is what tells us# the x-value of the cursorselectors=alt. , for quantitative fields), this is a D3’s number format pattern string. mark_bar), which take optional keyword arguments to configure the look of the marks. For example, the following uses mark_circle() with additional arguments to represent points as red semi-transparent filled circles: See also: aggregate documentation. Feb 22, 2022 · WTI_securities and color_list are both lists that are in the order requried for my mapping but I am returned with the following chart when I comment out the color line, I am able to get the following chart but I need the color mapping and legend. add_selection(nearest)# Draw points on the line, and highlight based on selectionpoints=line. Code: Whether the mark’s color should be used as fill color instead of stroke color. As a tribute, I wanted to regenerate the Economist graph(s) in "Mistakes, we’ve drawn a few": This is the code of a first shot: import numpy as np Use the Text Attributes panel to change the color of the text in the text window. Circle Mark Properties # A circle mark definition can contain any standard mark properties and the following special properties: Click to show table The text format specifier for formatting number and date/time in labels of guides (axes, legends, headers) and text marks. Vega-Lite provides a higher-level grammar for visual analysis, comparable to ggplot or Tableau, that generates complete Vega specifications. Bar Chart with Labels # This example shows a basic horizontal bar chart with labels created with Altair. So how can I do so ? I am new to programming and really a noob, workarounds/solutions ive seen so far didnt work. Note: The label text and value can be assessed via the label and value properties of the legend’s backing datum object. Default value: false for all point, line, and rule marks as well as geoshape marks for graticule data sources; otherwise, true. Axis Properties Properties for specifying a coordinate axis. Chart (data). mark_bar (). end == 'last' ). Text('sum(CARRIER_COUNT):Q', format='d') ) st. Chart(workload_df). The brush selection parameterizes the red guideline, which visualizes the average value within the selected interval. Whether the mark’s color should be used as fill color instead of stroke color. Here is an example: Jul 18, 2019 · What I intend to do is putting text-markers on the top of positive bars and bottom of negative bars (outside the bars without overlapping with the bars) Adjusting baseline or dy parameters dont seem to work in this case. // Single View Feb 26, 2021 · Interactively changing Altair mark text: possibility for background color? Asked 4 years, 7 months ago Modified 4 years, 7 months ago Viewed 1k times Area # area represent multiple data element as a single area shape. The mark property of a single view specification can either be (1) a string describing a mark type or (2) a mark definition object. ColorScheme altair. This document is adapted from the Bar Charts section of the Altair Example Gallery. here: #921 I want the user to be able to plot various lines onto a LayerChart, and select the color manually for each line added (i. Nov 23, 2024 · Altair chart mark_text background color/visual clarity Asked 11 months ago Modified 11 months ago Viewed 350 times Jun 11, 2018 · The opacity property in mark_text or in encoding don't seem to have any affect on title or axis' labels. mark_text(align='center',baseline='line-top',color='white'). If the format type is "number" (e. The same approach did not work for me, and after digging deeper I found that following example works differently: in jupyter+altair it plots multilines in jupyter+streamlit (same python env) it plots stringified version of array in a single line I believe the reason is that streamlit uses old vega-lite maybe? I can confirm after using . For example, the following uses mark_circle() with additional arguments to represent points as red semi-transparent filled circles: Watch this tutorial on enhancing visual clarity in Altair Charts with Mark Text Background Color. 5, the mark size is half of the bandwidth or the time unit interval. Other times it can be quite complex. Area Mark Properties # Click to show code Layered & Multi-View Charts # Along with the basic Chart object, Altair provides a number of compound plot types that can be used to create stacked, layered, faceted, and repeated charts. end == 'first' ). Learn how to improve the readability of your charts. I want values smaller than 50 not to be on the chart. Types of Box Plot # Altair supports two types of box plots, defined by the extent property in the mark definition object. Which version of Altair are you using? 5. If I additionally encode the color for the text object and resolve the colors independently I end up with this: Point # point mark represents each data point with a symbol. Example Customizing Visualizations Altair’s goal is to automatically choose useful plot settings and configurations so that the user is free to think about the data rather than the mechanics of plotting. Mark Properties # This section lists standard mark properties for primitive mark types. In this example, we’ll employ a little trick to isolate the x-position of the cursor: we add some transparent points with only an x encoding (no y Pie Chart # This example shows how to make a Pie Chart using mark_arc. ColorName altair. But there are a few more issues with your code: You are expanding your text layer from the bar plot, which already has the color parameter set. In Altair, marks can be most conveniently specified by the mark_* methods of the Chart object (e. For details on installing Altair or its underlying philosophy, please see the Altair Documentation Outline: The data The Chart object Data encodings and marks Data transformation: Aggregation Customizing your visualization Publishing a visualization online This tutorial is written in the form of a Jupyter In Altair, marks can be most conveniently specified by the mark_* methods of the Chart object (e. encode( alt. – Childream Jul 23, 2025 · Creating Basic Bar Charts In Altair, all visualizations start with the Chart class. Arc Mark Properties # Click to show code Bar Chart with a Temporal Axis # While the bar mark typically uses the x and y channels to encode a pair of discrete and continuous fields, it can also be used with continuous fields on both channels. Mark Edit this page Marks are the basic visual building block of a visualization. So maybe one of you has an idea how , for instance, to set the font size of the y and x axis seperately or both togehter (both ways d be nice). mark_point(). Color('TERMS:N', title='Carrier Terms') ) bar_text = alt. This section of the documentation outlines some of the ways to make these adjustments. By default, text mark as labels in Altair are positioned above or to the right of the value. Similar to scales, axes can be defined either at the top-level of the specification, or as part of a group mark. mark_bar(color = 'lightgreen', text = 'measure_max'). Note: For line segments that connect (x,y) positions to Sep 8, 2021 · I am using Altair to display a choropleth map. datum. Is there a way to implement this in Altair? . Chart(df1). Sharing interactive visualizations online extends the benefits to others. To view and set default color schemes, see the Config documentation. cars () bar = alt. mark_text() method doesn't work quite the other mark methods - . X('We Although it is possible to set all Chart properties as constructor attributes, it is more idiomatic to use methods such as mark_point(), encode(), transform_filter(), properties(), etc. C Jul 22, 2021 · Hey guys, I am trying to set the Font Size for the axes since the result is showing this way to small. encode (text="year:N") start_year = text. iowa_electricity dataset, because it's very straightforward. This class takes your data as input and uses methods to specify the type of chart and the encoding of the data. mark_bar(). If I encode the bar mark color to the categorical variable, this forces the text mark to also have these colors, despite selecting a different color in the "mark_text" method. They provide basic shapes whose properties (such as position, size, and color) can be used to visually encode data, either from a data field, or a constant value. Similarly, if the rule mark only has x encoding, the output view produces vertical rules that spans the height. In recent years, however, there have been new developments both in terms Channel Options # Each encoding channel accepts a number of channel options (see Channel Options for details) which can be used to further configure the chart. Chart(source). From the TextView toolbar, click the Text Attributes icon. there are three columns: date, which is a date; source, a categorical column with Vega - A Visualization Grammar. mark The color of the legend label, can be in hex color code or regular color name. import altair as alt from vega_datasets import data source = data. transform_filter ( alt. Altair Jul 18, 2018 · Here is an example from the docs where there is text on a bar chart. Line Mark Line marks are stroked paths with constant width, defined by an ordered set of (x, y) coordinates. At each of these steps, there are things that can go wrong, but Altair Color Schemes Color schemes provide a set of named color palettes for both discrete and continuous color encodings. If you are looking for more standard tooltips, see the Multi-Line Tooltip (Standard) example. Built on top of Vega-Lite, Altair focuses on simplicity, readability and efficiency, making it a favorite among data scientists and analysts. CompositeMark altair. mark_rect” tells altair to use rectangles as data points. e. Edit Legend Dialog Text over a Heatmap # An example of a layered chart of text over a heatmap using the cars dataset. Under Color, select Text. Nov 5, 2022 · I would like to add text (more specifically, percentages or actual values) to each category in my stacked grouped bar chart. Altair 5. Dec 10, 2020 · I'm creating a layered line chart with 2 lines in Altair, each with a custom color. 0 introduced a method-based syntax for setting channel options as a more convenient alternative to the traditional attribute-based syntax described in Attribute-Based Syntax (but you can still use the attribute-based syntax if May 3, 2019 · E. value(0),). Here's the data I used. value(0)))# Draw text labels near the points, and highlight The type specification influences the way Altair, via Vega-Lite, decides on the color scale to represent the value, and influences whether a discrete or continuous legend is used. Text('value:Q', format='. In Altair, marks can be most conveniently specified by the mark_* methods of the Chart object, which take optional keyword arguments that are passed to MarkDef to configure the look of the marks. ColorDef altair. altair_chart displays an interactive chart using the Altair library. 1. Chart(pd_df_chart). encode( x=alt. When trying to add labels to the map using mark_text(), I am unable to change the background color of these text boxes. Discrete color Mar 3, 2021 · I'm trying to use mark_text to create a stacked text in a stacked bar chart. X('DELIVERED_YEAR:O'), y=alt. For example, given a bar chart with a temporal field on x, we can see that the x-scale is a continuous scale. 0 The goal of this section is to teach you the core concepts required to create a basic Altair chart; namely: Data, Marks, and Encodings: the three core pieces of an Altair chart Encoding Types: Q (quantitative), N (nominal), O (ordinal), T (temporal), which drive the visual representation of the encodings Binning and Aggregation: which let you control aspects of the data representation within Besides the properties listed above, box, median, rule, outliers, and ticks can be used to specify the underlying mark properties for different parts of the box plots as well. . These mappings are then translated into detailed Circle # circle mark is similar to point mark, except that (1) the shape value is always set to circle (2) they are filled by default. Data Visualization: A Walkthrough in Altair This notebook is a follow-up to the visualization walkthrough. altair_chart(bar_chart + bar_text, use_container Pie Chart with Labels # This example shows how to layer text over arc marks (mark_arc) to label pie charts. altair. Unlike most other marks that represent one data element per mark, one line mark represents multiple data element as a single line, akin to area and trail. I am following the code exampl Oct 27, 2022 · The short version answer to your question is to use text=alt. Overview of external readers and the Altair Binary Format, the generic ASCII reader, running applications in batch mode, using Tcl /Tk commands, translators, and result math. import pandas as pd import altair as alt last_13 = pd. Upvoting indicates when questions and answers are useful. You can see that it has text placed above positive bars and below negative bars. I want to add a legend to this. For heatmap coloring, I use the “values” column and make it explicitly a Quantitative type. Aug 21, 2023 · Answer by Jorge Floyd Your bar chart specifies a stack order:,You should add a matching order encoding to your text layer to ensure the text appears in the same order. labelExprstr Vega expression for customizing labels. mark_text (baseline="bottom") ( Jul 19, 2019 · My question is regarding setting the size (width and height) of each of the cells in mark_rect (). Axis(labelAngle = -45, labelOverlap = False)), Jan 17, 2025 · The text "hazardous" on the plot looks blurry. Point Mark Properties # Click to show code By default Altair assumes for mark_geoshape that the mark’s color is used for the fill color instead of the stroke color. My x-axis is the “variable” column, and my y-axis is the ID column. xttyb eehedug olsb izm fdgjkezu icdvd uze evjg etzisuhc ctwu ifhxw ggearpbj eibdm xzyc obe