Plot types
The four plot types in Marple
The Time series plot is the standard plot type in Marple. Therefore it’s the most versatile! This might be obvious but time series plots allow you to visualise data that was recorded over time.
Dissolved oxygen in the Charles river in 2019
Within Marple time series plots, you can visualise multiple signals in one plot. This is also the goal of the platform. We want to show the correlation between signals as good as possible.
After clicking on a signal in the plot, the toolbar shows the settings that can be edited.
From left to right:
- Color: Change the color of the signal
- Style: Change the line style of the signal
- Limits: Change the limits of the signal: you can find more about it here. In short, it’s the max and min value of the y-axis for this specific signal
- Functions: This button allows you to do post-processing on the data and create calculated functions. Calculated Signals
- Up/Down arrow: Move the selected signal(s) up or down the list. Signals at the end of the list are plotted over signals earlier in the list.
- Annotations: this will toggle annotations in the plot (if they are available in the data). Annotations
- Toggle Auto Fit Y-Zoom: will automatically put every signal on the same axis. See the signal limits section on the Analysis page
- Export plot: allows you to make a PNG Image of your visualisation.
Initially, the scatter plot will be empty. Drag and drop or double-click signals from the signal list to the x/y or color signal fields to add them to the plot.
Empty scatter plot
After adding some signals it should look something like this:
Dissolved oxygen vs acidity in water
There are a couple of settings hidden in the settings wheel:
- Fit X/Y-axis: by default, the scatter will dynamically change the range of the x/y-axis in order to fit the data. If unchecked, the limits of the plot can be changed.
- Buckets: Choose to display buckets (rectangles) instead of dots. This is a more true representation of the data when it is sub-sampled.
- Filter Outliers: This will filter out points > 5 σ away from the median
There are also other plot options:
- Limits: When highlighting a signal, you can change the range of how the signal is displayed. For a signal on the y-axis, this will change the y-axis range. For a signal on the x-axis, this will change the x-axis range. Note that when ‘Fit X/Y-axis’ is enabled, you cannot change the limits on that axis.
- Up/down arrow: When multiple signals are displayed on the y-axis, change the overlay order
- Cycle signals(bottom left): Quickly switch around the x and y-axis signals.
A few closing remarks:
- In order to keep a smooth web-based experience, we need to sub-sample the data. This might cause your data to look a bit ‘fat’. You can change the resolution in settings.
- Scatter plots can currently only be made between signals that have the same time base
The map plot is used to represent geographical data, either on an OpenStreetMap or a custom background. To use the plot, drag & drop a latitude and longitude signal expressed in degrees onto the plot.
Zoom and focus: You can zoom and pan in the data by using the +/- icon or by dragging and scrolling in the plot.
From left to right the options in the toolbar:
- Latitude/Longitude signal: Set the color and offset for each signal
- Color signal: Add a color signal and set the color range
- Custom map: Set a custom map background
- Home: Reset the plot zoom
- Cursor focus: Focus the plot on the current cursor.
- Settings wheel: Additional options
- Size: set the bullet size
- Show full trajectory: Show the map plot of the entire time range as grey dots behind the regular map plot.
- Filter outliers: Remove data points>5σ from the median.
You can even be more precise by selecting a specific time with the cursor on the time series plot and seeing the corresponding position on the map plot.
Of course, you can simply zoom in and out on the map as well.
Custom background: you can add a custom background by selecting the custom map button, then upload your own background. To do this you will need to define the grid of your custom background.
Full trajectory: When zoomed in on the time series plot the corresponding points on the map are highlighted. To display points on the map outside the time series zoom level in grey or not show them at all. toggle this button.
Home button: to quickly reach or come back to the default zoom level, click on the home button.
Cursor focus: allows you to focus the zoom on your cursor
Frequency plot of dissolved oxygen levels
The frequency plot behaves and looks similar to the time series plot. It uses FFT to plot the selected time range in the frequency domain. Note that Marple assumes a constant sampling rate, and no missing data points, otherwise the plot may not be entirely accurate.
Frequency plot toolbar
From left to right:
- Signal settings: Color/Stroke Style
- Frequency range: Set the frequency range of the plot. You can also zoom in by dragging a selection as in the time series plot.
- Unit: set the unit of the x-axis (note: this mirrors the plot)
- Log Scale: toggle the scale of the y-axis between logarithmic and linear
- PSD: Show the plot as power instead of amplitude
- Remove DC offset: Remove the DC component of the frequency signal.
Last modified 1mo ago