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Map of the Month

Posted by ucfanlm at Aug 30, 2013 01:26 PM |

For August I have found a random Mexican Agriculture map that I came across while looking for some Central American maps for one of our academic staff.  The map shows Soil Potential of the Tlaxcala region at 1:10,000.  The village in the centre of the map is San José Atoyatenco which is 100km South East of Mexico City, it has now grown to be a large town.  San José Atoyatencois is over shadowed by the archaeological site of Xochitecatl located on a dominant summit of an extinct volcano (just south of town).  The map was produced in July 1944.

Mexican Agricultural Map - August Map of the Month

 

 

Shining a light on forest structure in Brisbane, Australia

Posted by ucfaam0 at Aug 29, 2013 02:49 PM |

by Mat Disney

One of my main research interests is how we can use remote sensing to measure and understand the state and dynamics of vegetation, particularly forests. By measuring different wavelengths of reflected sunlight e.g. from satellites we can tell a lot about vegetation properties: how much there is (sort of), the rate at which it is photosynthesising and taking up carbon, how it responds to stress or disturbance, and how it is responding to climate and anthropogenic changes.

One of the big difficulties we face is that remote sensing is just that, remote; we never get to measure exactly what we want to and so we have to try and infer it from reflected radiation. This is tricky because the signal we measure is a function not only of the vegetation colour (pigments, water content) but also to its structure i.e. how much vegetation there is, and how it is arranged. This is illustrated below in an image I took using my iphone from a light aircraft window over a rainforest in Australia. The variation in greenness is clear, but so is the variation in ‘lumpiness’ (structure) and density.

A temperate rainforest on Fraser Island, Queensland, Australia (image: M. Disney).

Forest structure encapsulates the biomass of the canopy i.e. how much carbon is stored in the tree, as well as how the leaves and branches are arranged. Current estimates of forest biomass are made using field surveys of tree diameter. This is near-direct, but is labour-intensive and can only cover small areas. Remote sensing potentially provides wide coverage, at the cost of directness. A new technique for measuring tree structure has developed over the last few years, using lidar, or light detection and ranging. Lidar measures the time it takes a laser pulse fired from the instrument to hit something in the canopy and return to the detector, allowing us to build up a 3D point cloud of laser ‘hits’ over the canopy. Lidars have been mounted on aircraft to measure canopy height and structure from above. However there is increasing interest in ground-based instruments, largely developed for surveying where there is a requirement for very precise 3D measurements. Collaborations between academia and industry have resulted in new instruments that have multiple wavelengths, allowing simultaneous measurements of canopy biochemical and structural properties. At UCL Geography we have developed highly-detailed 3D modelling methods, adapted from computer graphics, to understand how these measurements might be exploited (details here). We’re now using these models, along with various colleagues in the UK, Australia, Finland and the US (e.g. see here).

A Eucalyptus tree captured in 3D by the lidar scanner

A Eucalyptus tree (left), captured in 3D by the lidar scanner (centre) with the colours showing height above the ground (blue, low to red, high), and then (right) reconstructed into cylinders, allowing us to estimate volume, height and biomass. Manual measurements of the trunk diameter and height were 0.59m and 24m respectively, while the lidar-derived estimates were 0.55m and 23.9m (images: Andy Burt).

I was fortunate enough to spend Oct-Dec 2012 working with colleagues in Brisbane, Queensland to try out some of our new models and methods in collaboration with Dr. John Armston of DSITIA in Brisbane, and UCL Geography MSc Remote Sensing graduate Kim Calders (now a PhD student at Wageningen). As part of this work, I travelled with Andy Burt, a NERC-funded UCL Geography PhD student, to Brisbane at the start of August to participate in a unique experiment to test new lidar instruments for measuring forest structure. The experiment was organised by John (along with colleagues from DSITIA and UQ) and in collaboration with Terrestrial Laser International Interest Group (TLSIIG), a loose coalition of researchers interested in canopy lidar. The experiment brought together researchers from the UK, US and Australia to deploy five different lidar instruments with different capabilities at the same sites, allowing us to compare how each instrument sees the canopy structure. The only two dual-wavelength systems in the world (SALCA, developed by Prof. Mark Danson at the University of Salford, and DWEL, developed by Prof. Alan Strahler at Boston University and colleagues at CSIRO, U Mass Boston and U Mass Lowell) were joined by other, commercially-developed instruments scanning at single wavelengths, but more rapidly and some with finer detail.

The participants of the Brisbane laser scanner experiment July/August 2013

The participants of the Brisbane laser scanner experiment July/August 2013, standing behind more than $1M worth of various laser scanners!

Despite logistical challenges, the odd snake sighting, a few cuts and bruises, and with some lovely midwinter weather (“only” 20 C), the experiment was a resounding success. Discussions between the teams were very productive and we are already following up on how to use the data to provide new forest measurements. We were also visited in the field by Australian ABC TV news team to record a feature on the experiment (watch here). This unique experiment is the starting point to show how lidar can be used to complement measurements from satellite and those made using field surveys. We can also use the data to derive 3D tree models that we are using to explore ecological scaling laws describing how trees grow. These measurements have only ever been possible via destructive harvesting before.

As part of the next phase of this work, Andy, along with Kim and other colleagues from UCL and Wageningen, are in Gabon, West Africa, scanning tropical forest plots with lidar. More on this in a future post, when they return!

 

 

Left: Mat Disney and Dr. Rachel Gaulton (Newcastle University) measuring bark properties for use in 3D models of the trees which are being produced from the lidar measurements (image: M. Disney).

Right: UCL Geography PhD student Andy Burt scanning a forest plot at Karawatha Forest Park, using the Riegl VZ-400 lidar instrument belonging to Dr. John Armston and DSITIA Queensland (image: M. Disney).

 

 

Many thanks to John Armston for his hard work in organising the Brisbane field experiment – without him it would not have happened. Travel funds for Mat and Andy came in part from the NERC National Centre for Earth Observation and Andy’s NERC CASE studentship (with Infoterra/Astrium GEO-Information Services Division). We are also grateful for the support for this experiment of DSITIA, Queensland, the Terrestrial Ecosystem Research Network for use of site infrastructure, and the other members of the TLSIIG team.

Urban Mobility in Sofia between Routine and Revolution

Posted by ucfaam0 at Aug 08, 2013 10:31 AM |

by Anna Plyushteva

I came to Bulgaria to do fieldwork on urban commuting. Since April 2013, I have been looking at big new transport infrastructure – represented by the recently opened Line 2 of the Sofia Metro – from within the small, familiar practices of everyday travel. What better, my reasoning went, than a socio-technical disruption such as a new metro line, to illuminate the world of the mundane and the taken-for-granted? Well, disruption is exactly what I got, but of a somewhat different kind:  Bulgarians decided to bring down their government.

The peaceful protests began in mid-June, when the newly elected coalition government appointed as Head of National Security a hugely controversial figure (opinions on the street are in the rather narrow range between “mafia boss” and “mafia pawn”). I cannot do justice to the political reasons and outcomes of the unrest in this text; suffice to say that even though the appointment was withdrawn, public discontent grew. Every morning and evening, for over a month now, protesters have gathered in central Sofia. The demands are about transparency and accountability, targeted at a political establishment which has become synonymous with serving specific economic interests, including blatantly criminal ones. And for over a month, everyday travel in Sofia has been anything but mundane.

As I am writing this, sitting on a kerb during the second full-day blockade of Parliament, another evening of very unusual journeys home is descending upon the city. Key roads are shut off by protesters and police. The metro station which I had listed in my notes as the busiest station for evening commuters entering the system, is now known for being the destination for the thousands joining the protests after work. The new real-time bus stop displays blink improbable waiting times, as buses sit stranded far outside the city centre. Suddenly, the everyday journeys of my respondents begin and end in the most unexpected of places, at very  unusual times.

This could have been a very frustrating fieldwork situation to deal with, so I have thought up arguments to help me fight off the visions of PhD disaster. It helps that, on a personal level, I support the cause of the protesters, and am myself one of them. But even from a PhD perspective, there are reasons to appreciate what is happening.

Firstly, the “disruption” of “normality” has highlighted the fact that my account of everyday life practices should be more about on-going process of making and reconfiguring, and less about perpetual repetition of whatever I happen to frame as the “typical day”. The reason may be a new metro station, a headache, a new watch, or indeed civil unrest: in all cases, daily urban mobilities involve the continuous shaping of the everyday by weaving new with old. After 35 days of protesting in the same square from 6.30pm, my respondents have shared many insightful comments on how their bodies and minds “learn” places and situations, how they make new routines, sensing, thinking and moving with otherwise unusual spaces.

Secondly, that a porous definition of a research field can allow all kinds of interesting and important topics to seep into a project (and I realise that I may come to bitterly regret this). During the last month, the metro passengers from my PhD project have made me interrogate the assumptions built into my questions and methods much more carefully.  I had not planned to reduce respondents to mere “passengers”, dots whizzing between A and B and back again. But as the protests became Sofia's daily reality, it grew ever more important to locate the interest in commuting habits in relation to the myriad of subjectivities and environments that made up participants' everyday lives. Are the political beliefs of the interviewee relevant? Whether they own a dog (which must be walked before 8pm)? Their views on walking outside with an open beer can?

These are only some of the ways in which this project on daily mobilities is being illuminated from angles I did not anticipate. No big insights or exciting theories, a lot of work yet to be done and decisions to be made, and all kinds of traps to fall into. For now, I can see that thousands of people are craving political change, and even more people are loving the change happening already, in the city's streets. There is a six-lane road which is now a place where families spend the warm summer evenings sitting on the tarmac; kids are roller-skating, people are cycling, walking their dogs, eating ice creams. As I walk home just before midnight, Sofia's streets are quiet, and the air is cleaner than ever.

The transformation of one of Sofia’s busiest roads during the anti-government protests. Photo: author.

N.B.: This post was written on 18 July 2013. On 23 July, tensions in Bulgaria escalated. Protesters clashed with police during a blockade of the Parliament building, which left Members of Parliament trapped inside overnight.

Anna Plyushteva is a PhD candidate at UCL Geography exploring socio-technical change in the context of urban mobility. She is partially funded by a Doctoral Grant from the Economic and Social Research Council. More details on her research can be found here: http://www.geog.ucl.ac.uk/about-the-department/people/research-students/anna-plyushteva

Map of the Month!

Posted by ucfaam0 at Jul 31, 2013 03:09 PM |

Nick Mann from UCL’s Geography Department Map Room picks this month’s map.

This month I have pulled out an OS map of Fermanagh and Tyrone Sheet 45 (Ireland) dated 1903.  A first year student was looking at the map series as she wanted a detailed map of the coastline for her project.   It is one inch to the mile and surveyed in 1833 by Colonel Sir H. James.  The map has wonderful hill shading which gives it the 3D look this was engraved by hand at the OS office, Dublin under the direction of Captain Wilkinson.

OS map of Fermanagh and Tyrone Sheet 45 (Ireland) dated 1903

You can visit the extensive UCL Geography map collection in the Map Library and Reading Room in Bedford Way: http://www.geog.ucl.ac.uk/about-the-department/support-services/map-library

Welcome to the new UCL Geography blog!

Posted by ucfaam0 at Jul 31, 2013 11:42 AM |

We’re a team of 140 geographers working tirelessly in the pursuit of understanding the world better and making a difference through geographical research. The blog is produced by members of the Department of Geography to showcase our latest research and activities, and provide an interactive forum in which to discuss contemporary geographical issues affecting the world today.

We’re a diverse group here at UCL Geography: the department has over 60 academic and research staff and approximately 80 research students covering a broad range of research areas from recent environmental change, environmental modelling and past climates; to migration, geographic policy, urbanism and geopolitics. By anyone's standards, that’s a breadth of interest and expertise.

Comments are actively encouraged here! We’d love to hear from you so please feel free to comment on any of the posts. And if you’re feeling very passionately about it, you might like to contribute a post, please email geog-blog@ucl.ac.uk.