CH02 Paper and digital charts Flashcards
How is data quality shown on a paper chart?
Source diagrams are scaled replicas of the chart, showing the coverage, dates, scales and authority fotr the various types of source material.
Where info is insufficient for a source diagram, a written summary will be given.
How is survey method indicated?
The year of survey dindicates how the survey was conducted.
Define CATZOC A1
Position accuracy: ±5m
Depth accuracy: 0.5m +1% depth
Seafloor coverage: Full area search, significant seafloor features detected and depths measured.
Define CATZOC A2
Position accuracy: ±20m
Depth accuracy: 1.0m +2% depth
Seafloor coverage: Full area search, significant seafloor features detected and depths measured.
Define CATZOC B
Position accuracy: ±50m
Depth accuracy: 1.0m +2% depth
Seafloor coverage: Systematic survey, but some uncharted hazardous features may exist but are not expected.
Define CATZOC C
Position accuracy: ±500m
Depth accuracy: 2.0m +5% depth
Seafloor coverage: Depth anomolies may be expected.
Define CATZOC D
Position accuracy: Worse than ZOC C
Depth accuracy: Worse than ZOC C
Seafloor coverage: Large depth anomalies may be expected.
Define CATZOC U
Unassessed - the quality of the data has yet to be assessed, therfore other means are required to ascertain survey quality.
Which chart should the mariner navigate with?
The mariner should always use the largest scale chart appropriate for his purpose. Although when coasting a medium scale chart is usually sufficient.
Which foreign government charts does the Admiralty produce modified reproductions of?
AUS
NZ
JP
What would you use a Routing Chart for?
Published for the Atlantic (N/S), Pacific (N/S) and Indian Oceans.
Editions for each month of hte year.
Assists planning of an ocean passage for any time of year.
Outlines land areas and major ports.
Recognised shipping routes between major ports, with distances.
Data on wind speed, direction and force.
Incidence of low visibility and frequency of storms.
Data on sea and air temps, air press and ice limits.
Data on ocean currents.
Loadline zone limits and ocean weather ships.
How would you plan a great circle route?
Use a gnomic chart.
Straight line connecting start and end points.
Transfer the lat/long at 15deg intervals to mercator charts.
This give a series of rhumb lines.
What is a port approach guide used for?
They are for planning and execuing port approaches.
Restore situational awareness lost due to ECDIS screen size.
What info would you find on a port approach guide?
General information VTS information Warnings Overview and Admiralty products Dangerous cargo info Tidal info Port services Berth information Anchorages Pilotage Meteorological inforamtion
Where can info on chart agents be found?
NP131 - Catalgue of admiralty charts and publications.
