Antarctic expedition tracks

What you are looking at

Five lines: a sampled stretch of Cook’s second voyage, the approach of Endurance into the Weddell Sea, the trans-Antarctic crossing that was announced and never sailed, the drift of the beset ship, and the James Caird passage to South Georgia.

How to read this layer

Read the dash pattern before the shape. It says where the line came from, not what happened along it:

Most of what you see is dashed or dotted. That is the honest state of this dataset, and it will change as positions are compiled from the sources. One line is solid: the James Caird passage, whose vertices are the noon positions in Worsley’s log.

The planned crossing is the one line here that nothing ever travelled. It is filed as interpolation and drawn as such, so it cannot be read as a record of anything except an intention.

Historical scope

1773 to 1916.

Sources and evidence

Cook’s track resolves to the journals; the Endurance lines resolve to Shackleton’s published account and to the reanalysis of Worsley’s logbook. Four of the five locators are still pending and those lines are at raw. The James Caird passage is not: its positions were read out of the published transcription of Worsley’s navigational log (Bergman, Huxtable, Morris and Stuart, Records of the Canterbury Museum 32: 23-66, 2018) and it is at normalized - read against the source, not yet reviewed by a person.

Reconstruction and uncertainty

The drift is currently two endpoints joined by a straight line, which the drift certainly was not. It exists to prove the model can hold a drift as a different kind of thing from a voyage, and it is not a route anyone should measure.

The James Caird was the same kind of placeholder - three points of which the middle was ours - and is not any longer. It is now fifteen vertices: the departure position and the noon position the log gives for each day of the passage. Two limits stand even so. A noon-to-noon line says nothing about the path between two noons, and nine of the fourteen noons are reckoned rather than observed, which is why the line is filed as dead reckoning. The line stops at 8 May 1916, the last position the log works; the landing two days later has no position in the log.

Editorial decisions

A drift is not a voyage. When Endurance was beset the ship’s position went on changing for nine months while nobody steered anything, and the data model carries that as a property of the phase rather than as a note in a caption. No line in this layer that we drew is rendered as though a source had given it.

Data fields

evidenceClass, geometryProvenance, confidence, reviewState and act. See the Antarctic data fields.

Data and downloads

CC BY 4.0 for the compiled records. In review: not citable as established evidence.