planetmarshall

My First Full Scottish Winter Season

Posted on April 1, 2013 by Andrew — No Comments ↓

The Curtain, Bein Nevis (IV,5) As I write this, the Scottish winter is not just hanging in there, it’s colder now than it was in any of the Winter months and it’s likely I could yet get some more winter routes in the bag before the season is over, however I wanted to write this up while the memories were still fresh.

A couple of caveats – I’ve been in the Scottish Hills in Winter before, and as is often said there’s no such thing as Scottish Winter Hillwalking, only Mountaineering. That said, prior to this Winter my only experience of Scottish Winter Climbing was being guided up the Grade II North Gully on Ben Nevis at the end of a particularly foul week, weatherwise, in February 2012. So this is pretty much my first full season of Scottish Winter Climbing.

Probably one of the best ways to get out into the mountains as much as possible is to join a local mountaineering club. I’m a member of the Jacobites Mountaineering Club based in Edinburgh, a motley bunch of Munro and Corbett baggers, climbers, alpinists and ski mountaineers. In addition, I took a couple of weeks out to do some guided climbing with Martin Moran, based in Strathcarron in the North West, and also with Jagged Globe, based out of Ballachulish.

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Posted in Climbing

Solving Listener Crossword 4151 with Mathematica

Posted on October 12, 2011 by Andrew — No Comments ↓

Listener Crossword 4151

MathsJam is a monthly meeting for people interested in recreational mathematics, and drinking of beer. At the Edinburgh meeting in August, we were presented with this Listener Crossword, from The Times Crossword Club. At the time of writing, there are plenty of solutions on the web from those who tackled the puzzle in the traditional manner of brain, pen and paper. I opted to cheat.
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Posted in Mathematics, Software

Vancouver

Posted on October 1, 2011 by Andrew — 2 Comments ↓
Show topographic overlay

One of the advantages of my job is the ocassional opportunity to visit Vancouver. This is the first time I’d visited the city ( or Canada, in fact, though I have been to the US a few times ) and I wanted to make the most of the free time I had.


Having decided do go for a hike in the surrounding mountains, I only really had one full day free, limiting my options to what was easily accessible and returnable from in a day. Some of my colleagues had previously been to Grouse Mountain and mentioned it as a possible destination, but having never been higher than Ben Nevis ( at 1344m, 4409 ft, the highest mountain in the UK ) I wanted to use this opportunity to improve on that. Further to the west than Grouse, Cypress Provincial Park offers a number of peaks starting at around 1350m and steadily increasing in height as you go further north. These peaks form part of the popular Howe Sound Crest Trail, the full length of which is around 30km but I would only be doing the portion as far as The Lions – two 1600m peaks visible from Vancouver that are not entirely dissimilar from Garbh Chioch Mhòr and Sgùrr Na Cìche in Knoydart. From what I can ascertain, ascending The Lions themselves requires scrambling ( class 4 according to Wikipedia, though I have no idea what that is in UK terms ), however strange peaks in strange countries merit appropriate safety gear, so this time at least I would content myself to the summit of Unnecessary Mountain, which at 1530m fulfilled my "higher than Nevis" criterion well enough.
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Posted in Hiking

Adventures in Knoydart

Posted on September 5, 2011 by Andrew — 2 Comments ↓

Despite having been born and brought up for the first half of my life in Scotland, and having recently returned there, I have seen and explored little of it. Until recently I believed Fort William to be in the reasonably far north, despite the fact that the most cursory glance of a map reveals it to be only about halfway between Carlisle and Thurso. As part of what I hope will be a series of adventures to explore the rest of the land of my birth, I decided to venture into Knoydart, the region between Lochs Nevis and Hourn, at least partly inspired by the initial stages of the Cape Wrath Trail. The aim would be to reach Inverie, and its pub The Old Forge, the most remote pub in mainland Britain. Also, being of modest mountaineering ambitions, I would try to prefer high level routes where possible.

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Posted in Sport

An Illustrated Version of The Rime of the Ancient Mariner, for the Amazon Kindle

Posted on November 24, 2010 by Andrew — No Comments ↓

Cover image

A few months ago I jumped on the e-reader bandwagon, and purchased the latest version of Amazon’s Kindle device. By and large I’m extremely pleased with it; reading Douglas Adams’ Hitchhiker’s Guide to the Galaxy on a device that bears an uncanny resemblance to the eponymous guide itself ( something I’m not the first to notice ), brings me no end of amusement.

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Drawing geodesic curves using the Bing maps Silverlight control

Posted on June 30, 2010 by Andrew — 6 Comments ↓

For an upcoming post I wanted to be able to plot the shortest routes between various positions on the Earth using the Bing Maps Silverlight control. Although since I started working on the problem Bing have provided a similar feature with their Distance Calculator App, the functions are not available for reuse via the public API. Interested developers may just want to skip the maths and just download the code.

Geodesic source code for Silverlight 4.0

Geodesics

Geodesic

The shortest path between two points on an arbitrary surface is called a Geodesic, and on a sphere, it is a Great Circle. Modelling the surface of the earth as a perfect sphere, the shortest distance between any two locations on the surface is then described by a section of a Great Circle, ie an arc that lies on the plane that is described by the vectors between its start and end points and the Earth’s centre ( see figure 1 ).

With this information, one way ( and the way I have adopted ) to plot such a curve is as follows:

  1. Generate the points of the curve in two dimensions using the parametric equation of a circle.
  2. Transform the plane of the 2d curve into 3D space such that it intersects the end points on the sphere, and the sphere’s centre.
  3. Project the transformed points back into 2D space using the Mercator projection equations.

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Posted in Mathematics, Software

Visualizing the Prime Ministerial Debates

Posted on April 29, 2010 by Andrew — No Comments ↓
Nouns used by Gordon Brown

For the first time, the main Prime Ministerial candidates for the 2010 UK General Elections, will take part in three live debates. Since the BBC have kindly made the full transcripts available, I decided to have a go at analyzing the data and creating a visual representation in the form of word clouds. I am currently working on my own visualization software, but in the meantime these have been done using Wordle.

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Posted in Imaging, Software

Near Infra Red Pseudocolour using LAB Colour Separations

Posted on March 24, 2010 by Andrew — No Comments ↓
At the back of Clare College

As 2010 is the 100th anniversary of the first published infra red photograph, I thought I’d try my hand using my own digital camera and some easily acquired accessories. If you want, you can skip the theory and go straight to the description of the method and a script for Photoshop.

A quick overview of IR photography

The CCD that is responsible for recording the images photographed by most digital cameras, is already sensitive to the near infra red part of the spectrum. That is, the part of the spectrum outside of the range visible to the human eye, but not so far as that used for, for example, thermal imaging. Since most photographers are not interested in light that they can’t see, this light is usually filtered out by an infra red cutoff filter placed inside the camera body, directly in front of the CCD. However, such filters are imperfect, so with some camera models by CCD spectrum response combining a long exposure with an infra red transmitting filter placed in front of the lens, some of that IR light can be recovered. The figure shows the basic principle, though I should add that the graphs are just a sketch to illustrate the principle and don’t represent an actual CCD response curve.

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Posted in Imaging, Software

Winter Camping

Posted on January 21, 2010 by Andrew — 2 Comments ↓
Figured out the self timer

Last week myself and a group of friends took a winter camping trip up to the Lake District. An odd decision, it could be argued, seen as the region has recently seen both some of its worst flooding and coldest winters in recent years.  Nonethless, equipped with ice axe, crampons and a generous supply of Kendal Mint Cake we set out to climb Scafell.

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Silverlight and CUDA interop

Posted on January 15, 2010 by Andrew — 7 Comments ↓

mandrill
Update – source code now available

Microsoft have recently released a beta of Silverlight 4, which has limited support for native interoperation using COM. Potentially, this example could be applied to any number of native interop scenarios, however for this example I have chosen to use Nvidia’s CUDA technology.

Disclaimer : This is an example of what can be done, not necessarily, and in all likelihood, an example of how it should be done.

About CUDA

Up until around 2001 PC graphics cards, though powerful, implemented a fixed function pipeline that limited use to whatever was exposed by the APIs, usually Direct3D or OpenGL. The addition of a programmable pixel pipeline led to the use of graphics cards for more general computation tasks; at first using shaders directly, followed by higher level GPU specific programming languages, such as Brook, SH, and later NVidia’s CUDA. Most of this work was, and is, documented by the GPGPU group. NVIDIA’s website shows CUDA being used in a wide variety of applications but in practice it is best employed in so called “embarassingly parallel” problems.
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Posted in Software