Monday, 24 August 2015

Barnacle Geese Migration

Who doesn't like wildlife data? Also, the point and polyline data provides a means of testing the support of these data types in the QGIS d3MapRenderer plugin.

The MoveBank website stores animal tracking data which can be downloaded (subject to terms and conditions) as shapefiles for use within QGIS. The data for Migration timing in Barnacle Geese used in studies by Kölzsch et al. The data has been published by the Movebank Data Repository with DOI 10.5441/001/1.ps244r11. See For details about the project, data use etc. please contact the PI:

The data comes in six separate shapefiles, for points of timestamped GPS coordinates, and polylines linking the individuals being tracked from the Barents Sea, Greenland and Svalbard studies. After merging the point data into a single shapefile, and repeating this process for the polylines, the plugin can be used to export this data to a d3 web map along with a suitable Europe outline. The QGIS project background colour is also retrieved by the plugin and used as the background for the entire visualisation.

Note: Merging the data is not strictly necessary, as the plugin would be happy with six shapefiles. However, this allowed the line data to be selected as the main layer during the export. The main layer is used to set the initial extent of the visualisation, though the user may pan (if the pan and zoom option is selected) to view parts of the original shapefiles which were hidden.

The resulting visualisation used the Lambert Conic Conformal projection. The plugin calculates the center point, and extent from the maximum bounds of all the shapefiles included in the export. For conic projections in d3 the parallels parameter sets the top and bottom (latitude extents) of the projection, and the “rotate” and “center” parameters set the central longitude and latitude respectively. Again the plugin calculates this from the maximum bounds of all the shapefiles.

Barnacle Geese Migration tracks. Pan and zoom around the map.