Day/Date: Tuesday 14 June
Time: 9:15am
Locations: KiwiRail ferry in Cook Strait
Topic: Finding your way at sea and location technology
Experts: Jennifer Coppola - Nautical Cartographer, Land Information New Zealand
Speaking School: St Albans School, Year 5-6 and St Heliers School Year 7-8
Questions from St Alban's School
1. I wonder when you use echo-sounding to measure the depth of the ocean and what frequency works best? How deep can echo-sounding measure?
Frequency is the number of sound waves in a set time. Shallow water needs high frequency for echo sounding. Can measure depths of 1 or 2 thousand metres. Need to use low frequency for deep water as it penetrates better. High freq is more accurate as has moie data.
2. Have there been any earthquakes and other things that have changed the land (above and below the water)? Does that mean you have to make new maps?
Navy checked Lyttelton Port after Canterbury Earthquakes and was mostly OK. If there had been a underea landslides or damage to navigation lights LINZ would send a notification out and maybe update maps.
3. What are the names of the instruments you use to make the maps? How do they work? Do you use computers to make maps or draw them by hand?
They get a digital file from surveyors of xy or lat/long coordinates and use computers so no drawing by hand as it is much quicker. 6 months instead of 18 months to do a chart from start to finish.
4. Would you use the same techniques to find missing objects on the sea floor as you would to measure it (for example planes or boats)? What is the strangest thing you have ever found?
Jen says to find things an echo sounder sends a return signal from the sea floor - a hard object sends a stronger signal than say mud. Also a special (sideskin?) sonar is a cheap solution that cna find shipwrecks or planes on the sea floor. In the North Sea, Jen found a couple of shipwrecks. Also ocean trenches and fancy sand ripple patterns on the sea floor. Also old fish farms, you could sea old fish poo!
5. Do you have map proofreaders to make sure you haven’t made any mistakes? What happens if you make a mistake?
Jen says she has quality assurance people so everything gets checked. Especially important at sea becuase it is dangerous to hit un-mapped objects as you mostly cannot see them. If a "mistake" is found ie an unfound thing. Fortnightly publication called notices to mariners sent out so they can update their own charts. Lots of original sea surveys are really old.
Questions from St Helier's School
1. What do you need to study at school and university to have a job like yours?
Most have Geography or GIS background. Also surveying and mats. Geospatial career info at Futureintech web site http://www.futureintech.org.nz/
2. Did you always want to be a cartographer and why?
Jennifer says she had to think hard about this. Originally wanted to be a CSI scientist when started university. Got into this work so she could travel (Jen is from Canada) . Her grandfather was a cartographer in WWII so Jennifer thinks it is in her blood.
3. What did you learn in maths/science at school that you use today in your job?
Jen says she uses lots of maths but she says it is basic maths from primary and intermediate schools. Geometry like triangles, velocities, ratios, fractions, relationships, trigonometry.
4. Where has your job taken you around the world?
Jen is from Canada and has been to New Zealand, the North Sea, the Gulf of Mexico, USA, Antarctica. Liked the West Coast of NZ and her trip on the InterIslander today. Team mates here from Australia, UK, Philippines, Latvia.
5. Do you ever use your skills and knowledge when you go tramping and camping for fun?
Jen says no but is a bit embarrassed about it as she is really bad at reading land maps! Jen is better at things at sea like noticing navigation lights!
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