Theory 2 Flashcards
Not a characteristic of Raster charts?
Attribute tables linked to chart features
5 mandatory alarms?
- crossing safety contour
- deviation from route
- positioning failure
- approach to critical point
- different geodetic datum
What is data source for raster charts?
Paper charts that are scanned into digital format
How accurate is ECDIS?
Accuracy that meets or exceeds the accuracy of associated paper charts
Ecdis should be capable of identifying discrepancies between what two systems?
Any two positioning system methods available to ECDIS.
When using gps for positioning system, the SENC and GPS should be referencing the same….?
Geodetic datum
The responsibility of compiling accurate survey data, distribution data to users, and production of updates lies with?
The official hydrographic agency for particular region
What’s the greatest problem in datum mismatches?
They have potential to be catastrophic.
A chart object removed from SENC will?
Remain in the ENC
Which statement is true regarding raster data sets?
Produced by scanning hard copy (paper charts) images and are composed of pixels.
Display showing two motion vectors for own ship, one offset by several degrees from the other means?
One vector shows ships heading while other ships course over ground.
How many satellites are included in gps system ?
24 in low level earth orbits
Datum is?
A base reference point for measurements.
Which is a required feature for route planning?
Ability to access info from official publications
SENC does not include what?
Raster charts
Which display can you not remove info from?
Display base
Does manual updates affect the display ?
No
Can radar and arpa info be imported to display?
Yes
Which alarm is required for route monitoring?
When the scale in use is the largest scale supported by enc data format
What’s a periodic update?
An update that is required at the end of each voyage lasting greater than one week
And ECDIS display base is described as?
SENC info which is considered essential and cannot be removed from the display
Displayed scale is described as?
The ratio between a distance on the display and the real world distance it refers to
Ground stabiliser?
Owns ship motion referencing the coordinates of the earth.
A record is?
An entry in database that refers to all info on the associated row of the entry
True distance refers to?
Actual geographic distance considering reference datum
Description of SENC ?
A database resulting from the transformation of the ENC by ECDIS for appropriate use
What happens when a position fixing is lost?
ECDIS will provide indication
How are performance tests conducted during or prior to a voyage?
Either through automatic or manually activated functions
