Acceleration data window

Bursts

Modern tags support capturing acceleration data along with location data. As opposed to GPS data, acceleration data is captured as bursts. A burst is a set of measurements starting at a specific timestamp. These measurements do not necessarily align to a known GPS position as they are often recorded following a predefined schedule of fixed intervals. Acceleration data captured by tags captures the extent of x, y and z acceleration, quite similar to common smartphones.

Firetail supports you in the analysis of acceleration by visualizing bursts, and matching GPS measurements. Furthermore, Firetail allows to annotate arbitrary labels for user-selected intervals (see Section Burst annotation .

Note: the annotation of acceleration data in Firetail resembles the Movebank Acceleration Viewer.

Loading burst data

Downloading data with associated bursts can be done with our integrated Movebank download. Here we show experimental data from the Galapagos Albatrosses study (ID: 2911040), tag 131.

The screenshot above shows a number of bursts selected and highlighted in the map window.

Selecting a burst region

Selecting one or multiple bursts can be done using either by

1. a shift-left mouse button selection on the map
2. a shift-left mouse button selection in the acceleration data window

Deselect a region by a single click.

Burst annotation

Once you have identified and selected regions of interest Firetail provides means to assign labels these regions. We call these labels a category.

Add new categories

To add a new category press Add Category above the acceleration window

Assign a name to the category

The category will show up above the acceleration window

Assign a category to a region

Once you have defined categories, you can use the selection mechanism described above to define regions that you’d like to annotate with one of your categories.

1. Select a region within the bursts or the map
2. Press on the category’s name

The newly assigned category will be shown in a row above the acceleration data.

Save/Export annotations

Firetail offers several ways to export annotated data as comma separated values (CSV).

1. Select the File menu
2. Choose one of the available options explained below

Note: if no annotations are available in the current project, exported files will be empty

Save Annotations

This will save the annotations along with the downloaded movebank data. This will preserve your annotations across multiple Firetail sessions (restarts).

ACC bursts as CSV

This option will export acc bursts, together with your annotations.

You’ll be asked whether or not to include timestamp data or the start timestamp only. To better understand the difference, see this diff-view of both options:

ACC samples as CSV

This option will export acc samples, together with your annotations.

GPS as CSV

This will export the annotated region as separate track.

Activity Plot

For burst data, you can generate an activity plot for a tag/individual by using Window > Activity Plot

IMU magnetic field data

Tags by e-obs offer state-of-the-art solutions to animal tracking. Data gathered from these tags can be imported directly into Firetail using File > Open E-OBS Files.

Given data from an IMU (inertial measurement unit) is present, Firetail offers a visualization option to show the spatial orientation of the e-obs tracking device.

The raw data must be calibrated first to acquire accurate orientation values. Use Data > Calibrate e-obs IMU Data to fit an appropriate model [1] and calibrate the data accordingly.

You will now see the device orientation in a 3D viewport:

Glossary

For technical terms please refer to the incredibly complete Movebank Glossary.

References

1. Li, Q., & Griffiths, J. G. (2004, April). Least squares ellipsoid specific fitting. In Geometric modeling and processing, 2004. proceedings (pp. 335-340). IEEE.