echarts4r

The echarts4r project is licensed under the Apache License, Version 2.0.

This license allows you to:

• Reproduce, prepare derivative works of, publicly display, perform, sublicense, and distribute the work.
• Use the work for commercial purposes.
• Use the work royalty-free and without charge.

When redistributing the work or derivative works, you must:

1. Provide a copy of the license to recipients.
2. Include prominent notices in modified files stating that you changed them.
3. Retain all copyright, patent, trademark, and attribution notices from the source.
4. If a NOTICE file exists in the distribution, you must include a readable copy of the attribution notices contained within it.

You can configure a heatmap to use a calendar coordinate system. This is particularly useful for visualizing temporal data (like daily activity) in a grid format representing a calendar.

When using coordinateSystem = 'calendar', the data points should be formatted as [date, value] pairs. You can also specify a calendarIndex if multiple calendars are present in the chart configuration.

# Data structure for calendar heatmap
# Each value is a vector: c("YYYY-MM-DD", value)

data <- data.frame(
  date = c("2017-11-15", "2017-11-16"),
  value = c(28.718359, 17.431442)
)

echarts4r() %>%
  e_heatmap(
    data,
    coordinate_system = "calendar"
  )

When multiple charts are rendered in the same environment, setting brush_link = 'all' within the e_brush() function enables a global brushing mechanism. This allows a selection made on one chart to automatically highlight or filter corresponding data points across all other charts that have the brush component enabled.

echarts4r() %> {
  e_brush(brush_link = 'all')
}

The echarts4r package provides a low-level API for adding custom graphic elements to your charts. All graphic functions follow a naming convention where they end with the suffix _g.

# Available graphic functions:
# g_graphic_g (initialisation)
# g_group_g
# g_image_g
# g_text_g
# g_rect_g
# g_circle_g
# g_ring_g
# g_sector_g
# g_arc_g
# g_polygon_g
# g_polyline_g
# g_line_g
# g_bezier_curve_g

e_flow_gl is used to create flow visualizations, typically representing movement or directionality across a geographic or coordinate space. It utilizes WebGL for performance, making it suitable for large datasets of flow vectors.

To use it, you provide data points that define the flow, often including starting coordinates, ending coordinates, and potentially other attributes like color or magnitude.

You can create a calendar-based heatmap by providing a calendar configuration within the heatmap options. This is particularly effective for visualizing time-series data where each cell represents a specific date.

When using the calendar option, you can specify the range (e.g., a year like "2017") to define the temporal scope of the heatmap grid.

# Conceptual structure for a calendar heatmap
e_heatmap(data) |> 
  e_calendar(range = "2017")

The e_globe family provides 3D globe visualizations and is similar to e_geo_3d, e_map, or e_map_3d. To use assets like textures or environments, use the ea_asset() function from the echarts4r.assets package.

Note on Deprecations: The following functions are deprecated and should no longer be used:

• e_stars_texture
• e_globe_texture
• e_map_texture

echarts4r provides a wide range of geographical charting capabilities, including choropleth maps, 3D maps, and integration with Mapbox and Leaflet.

Key functional groups include:

• Registering Maps: Use e_map_register(), e_svg_register(), or e_map_register_ui() to register custom map data.
• Choropleth & SVG: Create maps using e_map(), e_svg(), or 3D variants like e_map_3d().
• External Map Providers: Integrate Mapbox via e_mapbox() or Leaflet via e_leaflet().
• Geo Components: Use e_geo() for coordinate systems, e_globe() for global views, and e_geoFacet() for faceted geo charts.
• WebGL/GL Features: For high-performance rendering, use e_flow_gl() (flow), e_lines_gl() (lines), e_scatter_gl() (scatter), or e_graph_gl() (graphs).

The brush_link argument controls how selecting items in one series affects others. You can specify which series should interact using the following values:

• "all": Interacts with all series (default).
• "none": Disables interaction between series.
• c(index1, index2, ...): Interacts only with specific series by their seriesIndex (e.g., c(3, 4, 5) to interact with series 3, 4, and 5).

# Example of linking specific series
e_brush(e, brush_link = c(3, 4, 5))