Hypo-theses

Prezi – First Impressions

Jul 152011

Yesterday I gave a talk at my university’s teaching innovation symposium on using gigapan and photosynth technology for providing and alternate learning experience for mobility impaired students who have difficulties undertaking geological fieldwork. As a potential teaching innovation for myself, and because I was going to be talking about using images at multiple scales, I thought it would be a good idea to experiment with Prezi rather than using a traditional PowerPoint presentation. I also thought it might be a good idea to blog my first impressions.

For those who are unfamiliar with Prezi, instead of having a number of individual slides, one has a single canvas on which all elements are arranged and a motion path is constructed between the elements. The presentation then follows the motion path, panning, rotating and zooming between the elements as necessary. This generates a smoother, virtually seamless presentation and this appeared to chime well with the zooming and panning of gigapan, and the theme of the talk that any alternative fieldwork experience must mimic the way in which geology students should approach an outcrop – overview first, the move in, examining features in detail around the outcrop, and then zooming out to reassess the exposure at a large scale.

[My most explored gigapan - Autobrecciated flow-banded rhyolites from Penfathach, Pembrokeshire]

The Prezi interface is quite intuitive following some simple tutorials with the placing and sizing of images and text. The presentations can be compiled on-line via their website for free (with a larger file storage allocation if you are in education) or they can be done off-line via a paid-for application. However, since there is a free 30-day trial of the off-line programme, I opted to try that. The basics are straight forward but I did find a few issues that did annoy me slightly. However, please bare in mind that I was using the software for the first time and I was under time pressure to write the talk quickly.

Image Size
What is not highlighted in the overview tutorials, but I did find in the ‘known issues’ section of the website only after I had written about half the presentation, was that the maximum permitted image size is 2880 pixels. Prezi will quite happily allow one to upload an image larger than this without any warning and issues only show up later when trying to show the presentation. Because many of my raw image from my Canon 5D are 4368 pixels I had to go back through the presentation, remove all the oversize images, resize the originals and insert the new copies.

Zooming
What I wanted to achieve was an effect where I had an overview of an image and then zoom into some small text inserted over an important feature, to highlight it. This works well except when the text is below a certain size. In such cases, the background image disappears leaving just the text. Whilst I can see that in some cases this might be useful, it wasn’t the effect that I was trying to achieve and there seemed no way that I could control the level at which the image disappeared. The only thing that I could do was to enlarge the text or extend the line length until the image remained in the presentation by trial and error. This resulted in having some text on the images that was larger than I really wanted.

Also the image vanishing wasn’t consistent. To rearrange things on the canvas, one can group them, move the group and then delete the group container leaving the moved elements. However, sometimes just moving an image with its text will cause an image to disappear when it remained before it was moved. Also, non-disappearing images in the off-line presentation would vanish when the presentation was uploaded onto the on-line site for sharing. This inconsistency was infuriating as I knew the effect I wanted to achieve but it was very frustrating getting it to work, testing the presentation over and over again. I also had to check that it also all worked at the resolution of the projected image as well as that when just editing on the laptop at a higher resolution.

Videos
Our university has only recently upgraded its wifi network. They have done a very good job (I can now connect to it on my iPhone for example where I couldn’t previously as it used a java login applet) but presenting in an unfamiliar room I wanted to not risk possible network issues and have every thing embedded in the presentation. Consequently, I used Camtasia to capture some demos of gigapans on the web and in Google Earth. Theoretically, the off-line version of Prezi can take a uploaded video file and then insert a converted file into the presentation. I simply couldn’t get this to work irrespective of which video format I tried to save the files in. I then tried uploading the videos to YouTube (successfully) and then insert these into the presentation as I had seen in the demonstrations. However, this would appear not to work using the off-line version. So I uploaded what I had of the presentation onto the Prezi website and then tried to insert the YouTube clips into this. This also failed to work.

By now I was running out of time. I had a half finished presentation and not much time left to complete it. I made the decision to put my trust in our IT people and their new wifi network, and break out of the presentation to run the gigapan, photosynth and Google Earth demos live. My trust was rewarded and everything worked on the day but there was more faffing about swapping from presentation to chrome, Google Earth and back than I would have liked.

I have subsequently discovered that if you enter the YouTube short URL as you are prompted to do by Prezi, this doesn’t work, but if you use the long URL from Camtasia or the advanced options from YouTube, it does. Consequently, I have now embedded some short clips into the presentation below.

Presenting
When it came to the presentation there were a few issues too. First, I like to walk about a lot when I present and use a remote control device to advance sides. However, all this does in Prezi is to zoom in or out of the canvas. I had to stand by the laptop on the lectern to advance the presentation manually. The layout of the room was such that the computer console lectern was one side of the room and the projection screen was the other. It was also very side on so I couldn’t easily see the projection screen from where I was giving the talk so I spent far too much time looking as the computer screen and not interacting with the audience. Manually advancing the presentation is done using the arrow keys. However, I am very used to PowerPoint where the advance can be done by hitting the space key, which is much easier. Unfortunately, in Prezi this swaps from presentation to edit mode. I did this several times by instinct and it did disrupt the flow of my talk.

I am also very accustomed to the presenter view in PowerPoint where you can see the next side coming up as well as the current one on the screen of the presentation laptop. This really aids the flow of my talks now and a couple of times I was a bit lost without it.

Conclusions
Would I use Prezi again? Very possibly. The effects are good and the presentation does stand out from the PowerPoint fatigue. With a little more practice and in a lecture theatre with a better layout I think the talk could have gone better. However, the inability to use the remote, pace about, interact with the audience and know what was coming next did hinder my delivery. Despite the greater complexity and fiddliness of putting a talk together I would probably use this again for conference presentations as I think the presentation did stand out, but for day-to-day lecturing use I’m sticking with PowerPoint. PowerPoint also allows the easier creation of lecture notes for students.

You can judge the results here. Obviously, there is no audio with this presentation but you should get the general idea.

Mistique II on Prezi

Western Mediterranean Earthquake July 7, 2011 Recorded at Keele, UK

Earthquakes Comments Off

Jul 082011

After a large earthquake of the other side of the world, this time an earthquake a little closer to home with a magnitude 5.3 tremor occurring in the Western Mediterranean Sea between France and Corsica. There seems to be not much information on this ‘quake. The EMSC indicate that it has a thrust fault mechanism with a northeast-southwest strike. It also appears to be in a region of little recent seismicity.

This event needed a bit of high-pass filtering to get it to stand out from the background noise but the result is clear enough to identify the P-, S-, and Rayleigh wave arrivals and obtain an epicentral distance of about 11-12° from the travel-time curves. Events closer than about 30° tend to have complex waveforms as they are travelling mostly through heterogeneous crust rather than homogeneous mantle.

More information:
USGS
EMSC
Earthquake-Report

Kermadec Islands Earthquake July 06, 2011, Recorded at Keele, UK

Earthquakes Comments Off

Jul 072011

This is the recording of the large Kermadec Islands earthquake of June 6, 2011, recorded on our schools seismology SEP seismometer here at Keele University in the UK.

Being at an epicentral distance of 155.3° from the epicentre, the first arrival is the PP phase as the direct P-wave is obstructed by the core.

The event is somewhat unusual as one would normally expect an earthquake of this magnitude along a subduction system to be a low-angle thrust event along the plate boundary between the Pacific and Australian Plates dipping gently to the west. However, the CMT focal mechanism determined is one of a normal fault. This event is right on the trench so it was possibly caused as the subducting Pacific Plate is forced to flex in order to subduct beneath the Australian Plate. The historical data show a magnitude 6.6 event from 2008, also on the position of the trench with a similar mechanism.

The ‘quake seems to have caused a ~1m tsunami wave locally but a more regional tsunami alert was cancelled.

Further details from the USGS.

Accretionary Wedge #35: Crozzle Redux

accretionary wedge, Staffordshire Comments Off

Jun 202011

Once again I find myself returning to a previous blog post with reference to the latest Accretionary Wedge, this time hosted by Evelyn Mervine of Georneys. The theme this month is favourite geology words. This is so difficult. I love the english language and the origin of words. In my first year structural geology course I try and include the origin of technical terms partly because I think it might help people remember them (e.g. graben = ditch in German, imbricate = roof tiled in Latin) and partly because I love the words themselves (e.g. parautochthon = nearly native [alongside the Earth itself] in Greek – I’ll leave Chris & Anne ‘allochthonous’).

So, what do I go for? As I have been working on Staffordshire geology for several years and the county has coal fields in both the north and south of the region, I have come across several old mining terms in the literature and many are, I think, beautiful words that need recording before they are lost forever. For example, Baum-pot is hole left by the removal of a tree stump from extracting a coal seam below (or a calcareous nodule in the Halifax Hard Coal); Bibbley Rock is a conglomerate; Clod-tops are clays above a coal; Creeshy Bleas are nodules of bituminous shale which fall out when the coal is worked away from beneath them; Horse Beans or Shaggy Metal is a stratum of a granular structure immediately overlying rock salt beds; Quoiceneck is greyish black clay with shining surfaces; Rattle-Jack is a carbonaceous shale. There are several other lovely geological mining terms given in a previous blog post.

A little more common, but largely unknown outside of coalfields is Cleat or otherwise known locally within Britain as back and cracks, board-way’s course, hugger, nannies, reed, smooths, thread or veises.

Cleat: Image from Coal Seam Gas Exploration and Production Services http://csgexploration.com/Structural%20Geology%20and%20Tectonic%20Analysis.html

The origin of cleat is somewhat debated. It appears to be extensional in origin and therefore, in least in part, due to contraction in coal formation as the carbonaceous material is devolatilised. However, if this was the sole cause then it would be expected that cleat would form a hexagonal pattern, similar to columnar jointing. Cleat, however, typically forms a rectangular pattern, with two types of cleat at right angles to each other and the bedding planes. One set of cleat, face cleat, is dominant and through-going. The other set, butt cleat, terminates at the face cleat planes so must be later than the face cleat. The orientation of face cleat can be consistent over large areas (in England it is typically north-south) so must tectonically controlled (in this case by a regional east-west extensional stress field). It is thought that the butt cleat forms as a result of later uplift and exhumation.

Although cleat has been a largely ignored and somewhat obscure structural feature, its properties are gaining a resurgence with the advent of coal bed methane extraction. Dropping the pore fluid pressure in a coal seam by draining the water allows the cleat to open up and methane released from the coal can travel to an extraction well via the permeability provided by the cleat. The degree and orientation of cleat development can therefore strongly influence the productivity of CBM. As the cleat is well-developed in North Staffordshire we have high hopes for our own CBM project.

So, I nearly went with cleat as my favourite geology word, but I really have to go with something more local and Staffordshire in origin. The Staffordshire Coal Measures have, in places, been quite strongly folded during the Variscan Orogeny. Where a thin shale is over- and underlain by sandstones, the less competent shales can get quite strongly deformed by thrusting or flexural-slip folding. The black, carbonaceous shales get contorted, burnished, and highly slickensided and were locally known by the miners as Hussle. Where the shales were not carbonaceous the miners of the Staffordshire/Derbyshire moorlands called the rock Crozzle. I think that this has a wonderful local, rural ring to it, so that is my favourite geology word – Crozzle.

Notes:
Crozzle and Hussle are first described by the founding professor of geology at Keele, Prof. F. Wolverson Cope in:
Cope, F.W., 1949. Crozzle and Hussle. Geological Magazine, 86, 36-42 doi:10.1017/S0016756800074094

For a more detailed discussion of cleat see:
Laubach, S.E., Marrett, R.A., Olson, J.E. & Scott, A.R., 1998. Characteristics and origins of coal cleat: A review. International Journal of Coal Geology 35, 175–207

I extracted the geology relevant mining terms in a previous blog post “Do you know your crozzle from your hussle? from the following:
Gresley, W.S., 1883. A glossary of terms used in coal mining, E & F.N. Spon, London.