Data anomalies

Ideally, each ship ID should correspond to exactly one ship. Unfortunately, the data set has some anomalies: some IDs are listed with different ship names or types. In some cases this clearly seems to be a typo (e.g. "SEASTAR ENDURANCE" and "ZBASTAR ENDURANCE" with ID 406999) but in other cases it is not so obvious.

To avoid doing manual data cleanup I assume that a (type, name, id) triple uniquely identifies each ship. In the cases where (type, name) pair has multiple corresponding IDs, I append the ship ID to its name to uniquely identify it in the UI.

Possible improvements

User experience:

• Avoid briefly resetting to world map when changing vessel type.
• Use different marker colors for start and end points.
• Display the map on the whole page with an overlay panel for vessel choice (like here).

Code quality:

• Avoid "objects are masked" warnings (possibly using loadNamespace).
• Add testthat unit tests for readShips.R.
• Avoid the overhead of remembering and filtering a data frame on user interaction (stateless session, type -> name -> observation hash map).

Recruitment points:

• Deploy to Google Cloud or AWS to show that I can use them ;)