Dot Plots
Learn about building and configuring dot plots in Mappica.
Overview
Dot Plots are versatile charts that arrange data points as dots in horizontal rows, with each dot representing an individual value in a series. Optionally, a bar can be added to each row to show additional information, such as the range between the maximum and minimum values or a confidence or prediction interval. By assigning distinct colors to each series of dots, dot plots can be effective at highlighting trends, patterns, or differences within a dataset.
Setup
In the Setup section, under the Chart tab, you can assign the following properties:
- The name will be used to reference it in the Layers tab and on the canvas.
- The top, right, bottom, and left Margin that will be added between the chart axes and the edge of the chart container.
Because the margin sets the space between the chart axes and the edge of the container, ensure you add enough margin for any axis ticks or labels. If needed, use options in the Axes section such as Limit Tick Width, Limit Tick Characters, and Rotate Ticks to constrain the size of tick and label text.
- The Size Ratio of the chart container. Since the chart will always take up the available width inside its parent section, the size ratio effectively determines the chart's height.
- Optionally, the chart's Minimum Height and/or Maximum Height. If the height calculated by the size ratio is smaller than the Minimum Height or larger than the Maximum Height, then the Minimum Height or Maximum Height is used instead of the size ratio.
Connecting to Datasets
In the
Dataset section, you can select the
dataset for your chart. If you need to add a dataset, this can be done by selecting
New Dataset in the
Project tab.
If you are on the Pro plan, you can upload your own files (in csv format) to use as datasets, by clicking New Dataset and then Upload Dataset.
After you have selected a dataset, you can optionally enable the Prefilter Dataset switch, which lets you filter the data that is supplied to the chart. The filter is a "prefilter" because it is applied before the visualization is generated; end users are unable to adjust the filter dynamically.
Next, the Data Format is displayed. You can select either Wide Data or Long Data. The data format should reflect the structure of the selected dataset.
Finally, choose the Fields that should be used to construct the chart:
- Vertical Axis Field: A text or date field for the chart's independent variable. Each unique value is displayed as an individual row of dots; any repeated values are aggregated.
- Series Field (for wide data): The chart's dependent variable, which is a number, percent, currency, or measurement field used for each dot series.
- Value Field (for long data): A numeric, percent, currency, or measurement field that serves as the chart's dependent variable. Each value in this field corresponds to a specific dot series, defined by the Color Field (found in the Color section of the right panel).
Connecting to Filters
You can establish connections to filter elements under the Chart tab, in the Connections section, by making a selection under Filter.
A
Filter element can be styled as a series of checkboxes, a dropdown menu, or a slider. Values from the specified
Filter Field appear as individual checkboxes, dropdown menu items, or (for numeric filtering) slider values. A given chart can be connected to one or more filters, and the same filter can be connected to multiple charts or other elements.
When a filter element is connected to a chart, it dynamically controls the dataset records displayed in the chart based on the user's selections. Filters can also adjust the chart's axis range dynamically, provided one of the chart's axis fields is the same as the filter's Filter Field and the Minimum and Maximum Range values of that axis are set to auto.
Additionally, filter elements can inherit color formatting from a chart, provided that the chart is using
Long Data format and the chart's
Color Field is the same as the filter's
Filter Field. For more information, see the
Color Formatting section of the documentation for filter elements.
If your chart uses
Wide Data format, use a
Selector element instead of a filter to dynamically control the chart color series.
Typically, the
Filter element you connect to will use the same
Dataset as the chart element. However, this is not strictly necessary. If the filter and chart elements use different datasets, the filter will only affect the chart if the chart's dataset contains a field (column) with the same name as the
Filter Field in the filter element. In this case, the values in these fields must at least partially align for the filter to take effect. Any non-matching values between the fields will be ignored during filtering.
Connecting to Selectors
If you are using Wide Data format, you can establish a connection to a selector element under the Chart tab, in the Connections section, by making a selection under Selector.
Selector elements control which series fields are displayed in connected elements that use a wide data format. Selectors can be displayed as checkboxes, dropdowns, or legends. While a chart can be connected to only one selector, a single selector can be connected to multiple charts and other elements that use series fields. Once connected, the selector element dynamically controls the dataset fields (columns) passed to the chart as series fields based on user selections.
Sorting
You can choose whether to reverse the chart's horizontal axis under the Chart tab in the Sort section.
Axes
The Axes section of the Chart tab is used to configure the Vertical Axis and Horizontal Axis:
- Add Label: When enabled, label text appears adjacent to the axis. You can also align the label text.
- Use Discrete Scale: By default, if the vertical axis is a date, number, currency, percent, or measurement field, it is formatted as a continuous scale, similar to the horizontal axis of a line or area chart. You can choose to switch to a discrete scale, where each unique value in the dataset is displayed as a distinct point, similar to the horizontal axis of a column chart.
- Customize Range: Specify a custom minimum and maximum value for the chart's horizontal axis.
- Set Axis Line Location: When enabled, this option lets you control the position of the axis line. Auto places the axis line at the bottom of the chart (in the case of the horizontal axis) or the left of the chart (in the case of the vertical axis). Zero aligns the axis to the zero value and Hidden removes the axis line entirely. If this option is turned off, the chart's independent axis line will be displayed in a default location and the dependent axis line will be hidden (Pro users can adjust these default settings in the Theme page).
- Customize Ticks: When enabled, you can control which tick values will be displayed on the axis. Values lets you specify exact tick values, which should be separated with commas. Choose Count to set an approximate number of ticks (this option is only available on axes displaying continuous data). Or choose Hidden to remove ticks from the axis.
If you choose to specify exact tick values, ensure that they don't overlap with one another on tablet and mobile viewports.
- Limit Tick Width: This is the maximum width, in pixels, applied to text on this axis. Leaving the tick width set to auto will result in tick text remaining on one line. Text wraps at spaces, so longer words will sometimes extend beyond the specified value. This option is only available when the vertical axis field is set to a text field.
- Limit Tick Characters: This feature allows you to set a maximum number of characters for tick labels. When enabled, longer labels will be truncated to fit the character limit, with ellipses displayed to indicate that the word has been truncated. You can specify a custom value or leave it at auto for default behavior. This option is only available when the vertical axis field is set to a text field.
- Rotate Ticks: On horizontal axes, you can rotate tick labels to angles of 0°, 30°, 45°, 60°, or 90°. This can improve readability, especially when dealing with long or overlapping tick labels.
- Use Short Format: On the dependent axis, you can display axis tick values in a compact format, such as 1K for 1,000 or 1M for 1,000,000.
The following chart formatting option applies to both axes:
- Clip Chart: Restrict chart items such as bars and symbols from extending beyond the boundaries of the chart container, ensuring all items remain within the outermost values on both axes.
Colors
Color formatting is defined in the Colors section under the Chart tab:
If the chart uses Wide Data format, separate colors can be assigned to each of the selected series.
If the chart uses
Long Data format, you can specify a
Color Field, which can be a text field or numeric (number, currency, percent, or measurement) field from the selected dataset. If you select a text field, each unique value in that field will be treated as a category and can be assigned a color. For numeric fields, you can configure a
Color Gradient,
Domain Minimum and
Maximum, and
Color Scale. These features are explored in greater detail in our
Colors page.
For certain chart types where using distinct color series is not essential, a Fixed color formatting option is available alongside the Variable formatting options described above. The option applies a single color to all chart elements and is supported for bar charts, column charts, arrow plots, and scatter plots.
To create a "ring" effect in your dot plot—a popular visual style—set the Fixed Dot Fill Color to match your page background color.
Bar Fields
Toggle on Add Bar Fields to draws bars between a Start Field and an End Field. The bars are layered underneath the dots, so they can be used to show the difference between maximum and minimum values or a confidence or prediction interval.
Your selected dataset format determines whether you can specify one or multiple bars per row of dots:
- If the chart uses Wide Data format, you can specify a single bar for a given row of dots.
- If the chart uses Long Data format, you can specify separate bars for each individual dot in a row of dots.
If you want to replicate Wide Data format and draw only one bar for every point on the vertical axis, add only one set of values to the Start Field and End Field columns for every item in the Vertical Axis Field. Leave other rows empty.
You have the option to further customize the appearance of bars as follows:
- Bar Color: Select this option to change the default bar color.
- Bar Width: Change the bar width (the default is 1.5px).
- Bar Start Symbol and Bar End Symbol: Use these options to display symbols at the ends of the bars. Options available include "Arrow," "Arrow (Reversed)," "Circle," "Outlined Circle," and "Tick." The symbols inherit the color and width applied to the rest of the bar.
