Plotting
def rerun.log_scalar(entity_path, scalar, *, label=None, color=None, radius=None, scattered=None, ext=None, recording=None)
Log a double-precision scalar that will be visualized as a timeseries plot.
The current simulation time will be used for the time/X-axis, hence scalars cannot be timeless!
See here for a larger example.
Understanding the plot and attributes hierarchy
Timeseries come in three parts: points, lines and finally the plots themselves. As a user of the Rerun SDK, your one and only entrypoint into that hierarchy is through the lowest-level layer: the points.
When logging scalars and their attributes (label, color, radius, scattered) through this function, Rerun will turn them into points with similar attributes. From these points, lines with appropriate attributes can then be inferred; and from these inferred lines, plots with appropriate attributes will be inferred in turn!
In terms of actual hierarchy:
- Each space represents a single plot.
- Each entity path within a space that contains scalar data is a line within that plot.
- Each logged scalar is a point.
E.g. the following:
t=1.0
rerun.log_scalar("trig/sin", math.sin(t), label="sin(t)", color=[255, 0, 0])
rerun.log_scalar("trig/cos", math.cos(t), label="cos(t)", color=[0, 0, 255])
trig), comprised of two lines
(entity paths trig/sin and trig/cos).
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
entity_path |
str
|
The path to the scalar in the space hierarchy. |
required |
scalar |
float
|
The scalar value to log. |
required |
label |
Optional[str]
|
An optional label for the point. This won't show up on points at the moment, as our plots don't yet support displaying labels for individual points TODO(https://github.com/rerun-io/rerun/issues/1289). If all points within a single entity path (i.e. a line) share the same label, then this label will be used as the label for the line itself. Otherwise, the line will be named after the entity path. The plot itself is named after the space it's in. |
None
|
color |
Optional[Color]
|
Optional RGB or RGBA in sRGB gamma-space as either 0-1 floats or 0-255 integers, with separate alpha. If left unspecified, a pseudo-random color will be used instead. That same color will apply to all points residing in the same entity path that don't have a color specified. Points within a single line do not have to share the same color, the line will have differently colored segments as appropriate. If all points within a single entity path (i.e. a line) share the same color, then this color will be used as the line color in the plot legend. Otherwise, the line will appear gray in the legend. |
None
|
radius |
Optional[float]
|
An optional radius for the point. Points within a single line do not have to share the same radius, the line will have differently sized segments as appropriate. If all points within a single entity path (i.e. a line) share the same
radius, then this radius will be used as the line width too. Otherwise, the
line will use the default width of |
None
|
scattered |
Optional[bool]
|
Specifies whether the point should form a continuous line with its neighbors, or whether it should stand on its own, akin to a scatter plot. Points within a single line do not have to all share the same scatteredness: the line will switch between a scattered and a continuous representation as required. |
None
|
ext |
Optional[Dict[str, Any]]
|
Optional dictionary of extension components. See rerun.log_extension_components |
None
|
recording |
Optional[RecordingStream]
|
Specifies the |
None
|