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Captain Cook in Google Earth: new user interface

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I have now applied the same range of techniques used for presenting Joshua Slocum’s first solo circumnavigation at: http://www.hazelhurst.net/Slocum to Captain Cook’s First Voyage Round the World at: http://www.hazelhurst.net/Cook

This means that all of the features introduced recently for Sailing Alone Around the World, like autoplay, passage highlighting, window resizing, and status information, mostly implemented using jQuery, are now part of the First Voyage for Round the World re-enactment.

Now, hopefully, I can get back to developing the Slocum voyage itself…

Copyright © Colin Hazlehurst, 2012

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Joshua Slocum in Google Earth: new features

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This morning I smartened up the presentation of Joshua Slocum’s first solo circumnavigation of our planet (see: http://www.hazelhurst.net/Slocum) by adding the following features:

Autoplay

When you click on a passage in the menu, that part of Slocum’s voyage is fetched from the server and starts playing in the Google Earth viewer as soon as it is loaded. In coding terms, I simply needed to add a call to the play() method after loading the tour:

          ge.getTourPlayer().setTour(tour);
          ge.getTourPlayer().play();

Improved cursor control

Previously, when the user clicked on a passage in the menu, I used the following jQuery expression to set the cursor icon to show that the user should wait for the passage to load:

          $('body').css("cursor":"wait");

This was quite hit and miss; the cursor would change to ‘wait’ but would frequently revert to the ‘hand’ as the mouse roamed over nearby anchor elements. By changing the jQuery to the following, this was resolved:

          $('*').css("cursor":"wait");

This code changes the cursor for all elements (“*”) so it doesn’t matter where the mouse moves, the cursor remains in the wait state until the passage is retrieved.

Status information

It can take several seconds to retrieve, parse, and load a KML file for display in the Google Earth plug-in, especially if there are multiple 3D models in the file. In addition to changing the cursor, I have added a line of status information which appears above the menu. This shows the text: “Please wait: fetching voyage…”. The text is removed as soon as loading of the KML completes. The jQuery statements for these actions are:

          $("#status").text("Please wait: fetching voyage...");

to show the message, and:

          $("#status").text("");

to remove it, where “status” is the id of the <p> element positioned where the status should be displayed.

Highlight current passage

Previously, it was difficult to know which passage was currently selected among the several that might be in the menu for a given chapter of the presentation. To remove any doubt, when the user clicks on a passage the text of that menu option changes colour (I’m English). I used the following code to achieve this effect – having first given each menu option a CSS class of “leg”:

          $(document).ready(function() {
              $(".leg").click(function() {
                  $(".leg").css({ "color": "#996615" });
                  $(this).css({ "color": "Blue" });
                  $("*").css("cursor", "wait");
                  $("#status").text("Please wait: fetching voyage...");
              });
          });

The function that handles the click event for a given element of the “leg” class will first change the colour of all “leg” elements to the default colour (#996615). This clears any previous selection. Then the function changes the colour of the text of the currently selected “leg” element, identified by ‘this’, to ‘Blue’.

As you can see, this is also the place to change the cursor and set the status.

Summary

I hope you agree that these features improve the usability of the presentation quite considerably. The fact that they were not built into the initial design reflects, to a large degree, that I am new to jQuery. This project started life as a .Net application but I am now more than content to convert it to Javascript.

Copyright © Colin Hazlehurst, 2012

If you enjoy the presentation of Joshua Slocum’s voyage, you might also like the First Voyage Round the World of Captain James Cook:  http://www.hazelhurst.net/Cook/

Captain Cook’s First Voyage Round The World

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The following slideshow and image gallery show screenshots taken from Captain Cook’s First Voyage Round The World, a presentation of Cook’s journal containing more than 15 hours of animation and audio.

This slideshow requires JavaScript.

To view the presentation, point your web browser to http://www.hazelhurst.net/Cook/ and install the Google Earth plug-in if you don’t already have it installed.

Copyright © Colin Hazlehurst, 2012

You might also like:

If you enjoyed Cook’s voyage, you might also like Joshua Slocum’s Sailing Alone Around the World, a similar virtual re-enactment of a famous sea voyage by the first single-handed circumnavigator; this presentation is still under construction.

 

Captain Cook in Google Earth: Batavia to Cape Town

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Endeavour sailed from Batavia on 27Dec1770. It was slow progress at first and they had to anchor the ship frequently to avoid losing ground against contrary tides and currents.

In Sunda Strait, the ship sailed within 3 miles of the island of Krakatoa, which must have had a very different appearance in January, 1771, than it did after its violent eruption in 1883.

Cook stayed over a week anchored off Prince’s Island, at the south-east end of the strait, to stock up on wood, water, and food before making the journey across the Indian Ocean to the Cape of Good Hope. They set sail on Tuesday, 15Jan1771 and progress was still slow owing to light and variable winds.

(See my previous post about the deaths of 23 members of the crew from dysentery)

Once she was in the south-east trade winds, Endeavour started to cover between 100 and 150 miles per day, arriving rather abruptly, and surprisingly, off the African coast on Tuesday, 05Mar1771:

In the evening some people thought they saw the appearance  of land to the Northward; but this appear’d so improbable that I, who was not on deck at this time, was not acquainted with it until dark, when I order’d them to sound, but found no ground with 80 fathoms, upon which we concluded that no land was near. But daylight in the morning proved this to be a mistake by shewing us the land at the distance of 2 Leagues off (about 6 miles).

Cook began to appreciate the strength of the currents that had carried Endeavour to the west and the south of her position determined by dead-reckoning. Remember that Cook did not yet have access to one of John Harrison’s chronometers and the determination of longitude was still a tricky business (though Cook was one of the most meticulous observers). On Wednesday, 13th Cook wrote in his journal:

Latitude observed 34 degrees 15 minutes South; Longitude in, by our reckoning, corrected by the last observation, 341 degrees 7 minutes West, or 18 degrees 53 minutes East from Greenwich, by which the Cape lies in 34 degrees 25 minutes South Latitude, and 19 degrees 1 minute East Longitude from Greenwich, which nearly agrees with the observations made at the Cape Town by Messrs. Mason and Dixon in 1761; a proof that our observations have been well made, and that as such they may always be depended upon to a surprizing degree of accuracy. If we had had no such guide we should have found an error of 10 degrees 13 minutes of Longitude, or perhaps more, to the East, such an effect the current must have had upon the ship.

I assume that the men Cook refers to were the British experts Charles Mason (astronomer) and Jeremiah Dixon (surveyor) who were commissioned in 1763 to resolve the border dispute between the British colonies of: Pennsylvania, Maryland, Delaware, and West Virginia. They had been in Africa because, like Cook, they were despatched on a mission to observe a transit of Venus (the 1761 transit). They never reached their destination of Sumatra and instead were forced to observe the transit from the Cape of Good Hope.

You can now view the part of Cook’s first voyage round the world between Batavia and Cape Town by visiting http://www.hazelhurst.net/Cook/. The website has over 15 hours of animation and audio presenting Cook’s voyage in the Google Earth plugin.

Copyright © Colin Hazlehurst, 2012

Captain Cook in Google Earth: Fevers and Fluxes

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His Majesty’s Bark Endeavour arrived in Batavia, Java, on 10th October, 1771. At this point in the voyage, more than 3 years after setting sail from Plymouth, the ship was in a very poor state and in need of a major refit. John Satterly, the ship’s carpenter provided Lieutenant Cook with a description of her defects, the majority of the damage being inflicted when Endeavour ran aground on a reef off Australia:

The ship very leaky (as she makes from 12 to 6 inches water per hour) occasioned by her main Kiel being wounded in many places and the Scarfe of her Stem being very open. The false Kiel gone beyond the Midships from Forward and perhaps further, as I had no opportunity of seeing for the water when hauled ashore for repair. Wounded on her Starboard side under the Main Chains, where I imagine is the greatest leaks (but could not come at it for the water).

By contrast, the men in were in good condition. The diet of his crew was constantly on Cook’s mind and he made every effort to procure fresh produce whenever possible. His journal entry for 15Oct1771 reads:

Monday, 15th. Fresh Sea and land breezes and fair weather. I had forgot to mention that upon our arrival here I had not one man upon the sick list; Lieut. Hicks, Mr. Green, and Tupia were the only people that had any complaints occasioned by a long continuance at Sea.

This was a great success considering the hardships, both physical and psychological, the men had endured. However, a mere 3 weeks after returning to ‘civilisation’ from the privations that attended their voyage of discovery the picture was very different. On Wednesday, 07Oct1771 Cook wrote:

Wednesday, 7th. Employ’d getting ready to heave down in the P.M. We had the misfortune to lose Mr. Monkhouse, the Surgeon, who died at Batavia of a Fever after a short illness, of which disease, and others, several of our people are daily taken ill, which will make his loss be the more severely felt; he was succeeded by Mr. Perry, his mate, who is equally as well skilled in his profession.

And another 3 weeks after this:

Wednesday, 26th. The number of Sick on board at this time amounts to 40 or upwards, and the rest of the Ship’s Company are in a weakly condition, having been every one sick except the Sailmaker, and old Man about 70 or 80 years of age. But notwithstanding this general sickness, we lost but 7 men in the whole: the Surgeon, 3 Seamen, Mr. Green’s servant, and Tupia and his servant, both of which fell a sacrifice to this unwholesome climate before they had reached the object of their wishes.

You have to feel for these men; they had rounded Cape Horn against wind and tide; they had taken their ship across the Pacific to Tahiti to observe the transit of Venus, then turned south to face more violent storms in search of a suspected southern continent; they had circumnavigated both North Island and South Island of New Zealand again with heavy swells and storm force winds; they sailed the whole of the east coast of Australia, sounding with a lead most of the way; they survived the grounding of the ship on the Great Barrier Reef when only their efforts at pump and windlass saved them; they proved there was a passage between Australia and New Guinea; and with a ship that was battered and worm-eaten they had limped to Batavia.

These giants of adventure were laid low by the microscopic organisms of dysentery: viruses, bacteria, protozoans, and parasites of various types. Too little was known of the mechanisms of dysentery and the preventive measures against it and they paid the price. The illness had no respect for rank; Mr. Monkhouse, the ship’s surgeon, Charles Green, the astronomer from the Royal Society, and Sydney Parkinson, natural history painter in the retinue of Joseph Banks, all eventually succumbed to the ‘flux’; and the disease ran through all other ranks including: the boatswain, the carpenter, the sailmaker, and a whole swathe of marines and seamen.

Cook completed his description of Batavia with the following text:

Batavia is certainly a place that Europeans need not covet to go to; but if necessity obliges them, they will do well to make their stay as short as possible, otherwise they will soon feel the effects of the unwholesome air of Batavia, which I firmly believe is the Death of more Europeans than any other place upon the Globe of the same extent. Such, at least, is my opinion of it, which is founded on facts. We came in here with as healthy a Ship’s Company as need go to Sea, and after a stay of not quite 3 months left it in condition of a Hospital Ship, besides the loss of 7 men; and yet all the Dutch Captains I had an opportunity to converse with said that we had been very lucky, and wondered that we had not lost half our people in that time.

What happened next is portrayed in a Google Earth presentation which plots Endeavour’s track after leaving Batavia. She was bound for England by way of the Cape of Good Hope. Not long after passing through the Straits of Sunda and while heading out into the Indian Ocean towards the trade winds, the men began to die. In the next 34 days there were 23 deaths. How very disheartening that must have been for the man who had kept scurvy at bay for 3 years and more.

Clearly, a bracing sea cruise is not the cure for dysentery. Cook felt that matters improved once they reached the trade winds, but the two screenshots above show the trail of death right across the Indian Ocean until Endeavour was to the south of Madagascar. Cook recorded the last deaths as follows:

Wednesday, 27th (February, 1771). Ditto Gales and Cloudy. In the A.M. died of the Flux Henry Jeffs, Emanuel Parreyra, and Peter Morgan, Seamen, the last came sick on board at Batavia, of which he never recover’d, and the other 2 had long been past all hopes of recovery, so that the death of these 3 men in one day did not in the least alarm us. On the contrary, we are in hopes that they will be the last that will fall a sacrifice to this fatal disorder, for such as are now ill of it are in a fair way of recovering.

To view the presentation described above, go to http://www.hazelhurst.net/Cook/ and select ‘Batavia to Cape of Good Hope’ in the menu system; then click on ‘Fevers and Fluxes’.

Copyright © Colin Hazlehurst, 2012

Captain Cook in Google Earth: migration to the web complete(ish)

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I have been working for a couple of weeks converting my Google Earth presentation of James Cook’s first voyage round the world so that it runs in a web browser using the Google Earth API.

All of the Google Earth ‘tours’ are now transferred to www.hazelhurst.net/Cook/ providing more than 15 hours of animation and audio. I hope that education and GIS professionals as well as those interested in adventure, exploration, and discovery, will find this presentation interesting and useful.

There are several advantages to the new site:

  1. The menu system makes it easy to find the part of the voyage that interests you.
  2. All of the legs of the voyage are accessible from the menu; previously you had to load each tour separately into the Google Earth application. The ‘ish’ in the title is there because I have not yet prepared the section of the voyage from Batavia to England and I have not included the passage from Cape Horn to Lagoon Island. For the sake of completeness I will add these sections at a later date.
  3. The tours in the presentation are each limited to about 10 minutes duration, and they now load much faster than they did in Google Earth.
  4. After completing a large part of this project I realised I needed some  automation tools. Consequently, I developed TourMaker which uses <ExtendedData> attached to <Placemark> elements to describe how the 3D model should be moved. This eliminates much of the manual effort required to create animations in Google Earth; this in turn made it easier to model Cook’s voyage in finer detail. I particularly like how Endeavour now rounds Cape Horn and later visits a string of South Seas islands both on the approach to Tahiti and on leaving that island after observing the transit of Venus.
  5. I have made fresh sound recordings of much of Cook’s journal; I bought a copy of WavePad to do this and, as in many other situations, I discovered the need to do the job twice: the first time to learn how to do it, and the second time to do it properly. The early recordings were rushed, the levels were inconsistent, and the sound effects were too prominent. I hope these issues are now resolved.

Copyright © Colin Hazlehurst, 2012

Captain Cook in Google Earth: South Island, New Zealand

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Doubtful Bay

…and today, I added the exploration of South Island, New Zealand to the website, which can be found at:  www.hazelhurst.net/Cook/

The screenshot shows Endeavour off Doubtful Bay; ‘doubtful’ because it was not certain that, having once entered the bay, it would be possible to bring the ship out without a long wait for a suitable wind. There were steep cliffs rising to high mountains on both sides of the bay, so only a wind blowing out of it would allow the ship to be manoeuvred. Cook judged that this would occur only one day per month.

Copyright © Colin Hazlehurst, 2012

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