GeoGarage blog

Sunday, March 10, 2019

Thomas Coville, professional solo sailor, heroes of the unpredictable

Thomas Coville, Professional Solo Sailor| Heroes of the Unpredictable from Helly Hansen

Saturday, March 9, 2019

The Tangaroa Expedition (The Kon-Tiki Expedition) 2012 Documentary

All his life, Olav Heyerdahl had heard the stories of his grandfather: of how he crossed the Pacific in 1947 on a primitive raft made of balsa wood.

Now at last, he got to experience it first hand.

As a tribute to his grandfather and the original Kon-tiki expedition, Olav and his team built a new raft in Peru and sailed it all the way to Raiatea in French Polynesia.

When they arrived on the 24th of July 2006, after four months at sea, over a thousand people greeted them in a traditional Polynesian welcoming ceremony.

This is a spectacular and unique documentary of the modern day voyage, with footage of the 1947 expedition setting the context.

The 1947 Kon-tiki film won an Oscar, and Thor Heyerdahl's book has sold more the 50 millions copies worldwide.

At the time, the whole world was amazed by this eccentric Norwegian explorer.

The story continues to enthral 60 years later, only this time in colour.

Friday, March 8, 2019

Maiden review – raging seas and sexist squalls

For the International Women's Day 2019 a souvenir : voyage of a courageous pioneer... Maiden

Maiden made history in 1990 when its female crew, led by Tracy Edwards, became the first to sail the Whitbread Round the World Race.

Photo : Dogwoof

From The Guardian by Peter Bradshaw

Tracy Edwards is the British sailor who made history in 1989 by skippering the first all-female crew in the Whitbread Round the World yacht race.
This film tells her story and those of her crew members, as they faced sexist squalls from male competitors, who as greying interviewees don’t look best pleased even now to be talking about when and how Tracy beat them.
There was also the press.
The Guardian’s Bob Fisher comes in for some criticism.

Edwards showed a staggering amount of leadership and energy on dry land, as well as at sea, assembling her crew and persuading the King of Jordan to provide vital sponsorship.
The boat was coyly called Maiden, and Alex Holmes’s film also shows how it punningly bore the banner “Maiden Great Britain”.
Their success was also a matter of patriotic pride.

https://www.maiden.film

The incredible, against-all-odds story of sailor Tracy Edwards, who skippered the first all-female international crew in the 1989 Whitbread Round the World Yacht Race.

Holmes recreates their adventure, using a lot of home movie footage of her childhood and early life – this appears to be the real thing, although sometimes I wondered if faux Super 8 reconstruction was being used – and also the TV coverage from 1989, with much toe-curling Partridgean commentary from Frank Bough and Fred Dinenage.
At one stage in the race, Edwards cunningly manipulated the paparazzi by getting the entire crew to wear glamorous swimming costumes on deck: they each look surreally like Princess Diana aboard Dodi Fayed’s yacht – but maybe that is simply the era.

Tracy Edwards experienced her “first real taste of sexism and misogyny” when she sailed around the world with an all-female crew from 1989 to 1990 — but almost 30 years later, “Maiden” director Alex Holmes doesn’t think much has changed.

There is something that the film doesn’t address as clearly it could have done.
In 1989, Edwards was asked if she was a feminist and she said no – and that she hated the word. It’s probably clear enough what she meant: she just wanted an equal shot at yachting success, just as the then prime minister Margaret Thatcher once wanted an equal shot at political success.
But, given that the present-day Edwards is interviewed at length, Holmes could perhaps have given her another chance to consider that question.
At all events, it pays due homage to Edwards as a courageous pioneer.

Links :

Thursday, March 7, 2019

Fun fact: GPS uses 10 bits to store the week. That means it runs out... oh heck – April 6, 2019

GPS Week-Number Roll-Over (WNRO) problem

From The Register by Shaun Nichols

Nav gadgets will be Gah, Properly Screwed if you don't or can't update firmware

Older satnavs and such devices won't be able to use America's Global Positioning System properly after April 6 unless they've been suitably updated or designed to handle a looming epoch rollover.

The worldwide precise time broadcasting performed by the GNSS constellations (GPS, Galileo, GLONASS, Beidou) is the most strategic and vital asset for all our society infrastructures.

picture courtesy of Marco Lisi, ESA

GPS signals from satellites include a timestamp, needed in part to calculate one's location, that stores the week number using ten binary bits.
That means the week number can have 210 or 1,024 integer values, counting from zero to 1,023 in this case.
Every 1,024 weeks, or roughly every 20 years, the counter rolls over from 1,023 to zero.

The first Saturday in April will mark the end of the 1,024th week, after which the counter (WN = Week Number) will spill over from 1,023 to zero.
The last time the week number overflowed like this was in 1999, nearly two decades on from the first epoch in January 1980.

You can see where this is going.
If devices in use today are not designed or patched to handle this latest rollover, they will revert to an earlier year after that 1,024th week in April, causing attempts to calculate position to potentially fail.
System and navigation data could even be corrupted, we're warned.
"GPS devices with a poorly implemented GPS Time-to-UTC conversion algorithm may provide incorrect UTC following a week number rollover," US Homeland Security explained in its write-up (PDF) of the issue this week.
"Additionally, some GPS devices that calculate the week number value from a device-specific date rather than the start of the current GPS Time Epoch may provide incorrect UTC at some other device-specific date."

As the Reg reader who tipped us off to the shortcoming noted, this could be a significant headache for data centers that use GPS timing for synchronization.
"Decent vendors should have patches. But who has been thinking about this?" our tipster told us.
"This could be a low-key Y2K style bug all over again, but with companies doing less preparation."

Fortunately, devices on sale right now should be prepared for this rollover and handle it gracefully.
Uncle Sam's GPS nerve-center GPS.gov says (PDF) receivers that follow the ICD-200/IS-GPS-200 specification should be able to deal with the week number overflow.
This basically means newer receivers built after, say, 2010 should be fine, provided they follow the specs and notice the rollover.

The creation of the GPS which serves as a reference to the epoch is January 6, 1980
About 20 years later, on August 21, 1999, the first Week Number Rollover
About 20 years later, on April 6, 2019, the next Week Number Rollover

To put it another way, if your gadget goes haywire in April, it's probably because of this.
If it works as normal: brilliant, it's not affected.
Consider yourself forewarned.

GPS.gov also notes that the new CNAV and MNAV message formats will use a 13-bit week number to solve the epoch migraine right up until the planet becomes uninhabitable via climate change or we all blow ourselves up.

Beware of the sudden profusion of sales of used GPS on ebay, which you will know with full knowledge of the facts that they will no longer work in a few days if that is not already the case.

source : Retro-GPS.info

Information from Furuno
For impacted GPS, a simple cold start (after resetting the almanacs/ephemerides) may solve the problem as it can permanently crash the GPS.
Note from Furuno : The date specified above is the date in which week number rollover occurs in our products listed above, and the date is independent from the one announced by the US Department of Homeland Security, namely, the 6th of April 2019, which is the date when GPS week number rollover occurs in the GPS as a system per se.
The difference stems from different initial dates of counting week between GPS system and the GPS chipset used in our products.

For devices unprepared for the counter overflow, a firmware upgrade will be necessary to keep the things working properly.
GPS.gov recommends those unsure about their readiness for the turnover, particularly enterprises, should consult the manufacturer of their equipment to make sure they have the proper updates in place.

Links :

The Next Web : GPS satellites have a little-known ‘Millennium Bug’ problem of their own
Orolia : The GPS 2019 Week Rollover - What You Need to Know
Spirent : The GPS Week Number Rollover problem
XYHT : GPS Week Rollover – Don’t Panic, but...
The Sync channel blog (2015) : Simulating GPS Week Rollover with the Tria GPS
UNB : The GPS End-of-Week rollover
Redit : GPS Date Error as of GPS Week 1000
DHS published guidelines
GPS simulators, such as LabSat 3, can be set up to test for issues arising from the GPS Week Rollover event.
AppStore : GPS Time Converter
The Register : Brit boffins build 'quantum compass'... say goodbye to those old GPS gizmos, possibly

Wednesday, March 6, 2019

Citizen scientists to help map the reef

Undersea map near Townsville.

Great Barrier Reef with the GeoGarage platform (AUS nautical chart)

From James Cook University by Robin Beaman

James Cook University is calling for volunteers to help map the seafloor around the Great Barrier Reef to better protect the natural icon.

BBC – Great Barrier Reef with David Attenborough (2016)

David Attenborough returns in this landmark series to his most magical place on earth exploring the Great Barrier Reef aboard the research vessel Alucia.

Part 1: Builders David descends beneath the waves at night in the state-of-the-art Triton submersible, the first of its kind to visit the reef.

He meets some of the tiny coral animals that built the reef and helped to turn it into an underwater wonderland.

He then takes to the skies to witness the vast scale of their endeavour, a living structure that provides a home for thousands of species.

Using cutting-edge technology to generate computer scans of the sea floor, David learns that the Great Barrier Reef we know today is much younger than scientists ever imagined.

He meets some of the people that have lived alongside it and who have told stories of its origins for thousands of years.

JCU marine geologist Dr Robin Beaman said the Royal Australian Navy does great work mapping the main shipping channels and hazards to navigation such as coral reefs, but there are still many areas that need to be mapped.

“Around 40% of the vast Great Barrier Reef shelf has been mapped with digital depth soundings using modern equipment, but there are some remote areas lacking any digital depth data,” he said.
Dr Beaman said there was an untapped resource that could be used to help fill the gap.
“Many vessels on the Reef use relatively sophisticated echo sounders, combined with GPS to measure the depth of water and conduct safe navigation. They give a good picture of the seafloor, but the problem is the data are not logged – it just appears in the moment and then is lost,” he said.

Argo Expeditions Boat Aerials from BIOPIXEL on Vimeo.

Argo Expeditions Boat Aerials from Biopixel

In 2018, together with underwater-film specialists Biopixel and their expedition vessel ARGO, the JCU team tested a SmartLog USB data logger, developed by TeamSurv in the UK.
Depth and GPS position data are downloaded through the SmartLog direct to a USB stick.
The Great Barrier Reef Foundation has provided $10,000 to the group to install loggers onto volunteer vessels.
“The SmartLog innovation will enable us to put many more sets of ‘eyes’ in the water to give scientists an accurate picture of the Reef right now and to help map areas of the Great Barrier Reef that we know very little about,” Great Barrier Reef Foundation Managing Director Anna Marsden said.
“It’s a unique opportunity for citizen scientists to easily capture and deliver valuable data to Reef scientists that can be used to inform restoration and adaptation efforts on the Reef.
“Ultimately the Reef will benefit from these types of innovations and the Great Barrier Reef Foundation, with support from our corporate partners, is pleased to be able to help elevate this project to the next level,” she said.
“We have partnered with the Great Barrier Reef Foundation to establish a pool of SmartLog USB data loggers in Cairns. The Citizens of the Great Barrier Reef are also involved, which gives people a role in contributing valuable citizen science data to improve a dataset that helps the Reef,” said Dr Beaman.
He said the group is mainly looking for expedition-style vessels that may travel multiple days to remote parts of the Reef, and that also have GPS navigation and echo sounder systems onboard.
“It’s a simple process to install the SmartLog and the ongoing maintenance just involves collection of the depth data off the USB stick,” he said.

A raft of detailed new bathymetry datasets

have recently been published on the AusSeabed Marine Discovery Portal.

Dr Beaman said the aim is to use the new depth data to improve the accuracy of the 3D depth model of the Great Barrier Reef.
“The shape of the underwater landscape, with its shallow and deeper reefs, pinnacles, holes and channels, influences the path of seawater carrying cooling waters, nutrients and sediment through the reef matrix.
“Detailed knowledge of the seafloor depth is critical for understanding the distribution of seabed habitats, to provide data for coastal inundation forecasting, flood plume modelling and crown-of-thorns starfish control efforts,” he said.

Dr Beaman said the 3D depth data will be also shared with the International Hydrographic Organization’s Data Centre for Digital Bathymetry and the Australian Hydrographic Office.
Volunteers can apply to be part of the project here

Links :