FREE EPRINT: Assessment of low altitude UAS flight strategy on DEM accuracy, Earth Science Informatics
Soil erosion, rapid geomorphological change and vegetation degrada-
tion are major threats to the human and natural environment. Unmanned Aerial Systems (UAS) can be used as tools to provide detailed and accurate estimations of landscape change. The effect of flight strategy on the accuracy of UAS image data products, typically a digital surface model (DSM) and orthophoto, is unknown. Herein different flying altitudes (126-235 m) and area coverage orientations (N-S and SW-NE) are assessed in a semi-arid and medium-relief area where terraced and abandoned agricultural fields are heavily damaged by piping and gully erosion. The assessment was with respect to cell size, vertical and horizontal accuracy, absolute difference of DSM, and registration of recognizable landscape features. The results show increasing cell size (5-9 cm) with increasing altitude, and differences between elevation values (10-20 cm) for different flight directions. Vertical accuracy ranged 4-7 cm but showed no clear relationship with flight strategy, whilst horizontal error was stable (2-4 cm) for the different orthophotos. In all data sets, geomorphological features such as piping channels, rills and gullies and vegetation patches could be labeled by a technician. Finally, the datasets have been released in a public repository.
This paper outlines a collaborative project between a group of Fine Art and Geography students who helped develop and contribute to a conversation about recording ‘place’. Introducing methodologies from both disciplines, the project started from the premise of all environmental ‘recordings’ being ‘inputs’ and so questioned what could be defined as ‘data’ when encountering a location. Brunel’s Grand Entrance to the Thames Tunnel (London) provided the motivation for 10 objective and subjective ‘recordings’ which were subsequently distilled into a smaller subset and then used to produce a short film that was presented at an international conference. Important to the collaborative nature of the project were ongoing opportunities to share equipment, techniques, material and references across disciplines. It was an experiment to measure the potential for ‘mapping’ to capture physical and historical information, as well as embodied experience.
FREE EPRINT: Land inundation and cropping intensity influences on organic carbon in the agricultural soils of Bangladesh, Catena
Land inundation is a common occurrence in Bangladesh, mainly due to the presence of two major river systems -the Brahmaputra and the Ganges. Inundation influences land use and cropping intensity. However, there is little information on the influences of the extent of flooding and cropping intensity has on soil organic carbon (SOC),particularly at the landscape level. To investigate these influences, we collected 268 surface (0-30 cm) soil samples from 4 large sites within the two alluviums deposits (the Brahmaputra river and the Ganges river), on a regular grid (1600 m). The findings show that SOC levels are generally low, reflecting the intensity of agriculture and land management practices. SOC variability was higher across the medium high land (MHL) and medium low land (MLL) sites than in the high land (HL) and low land (LL) sites. The relatively low SOC levels and variability in the HL sites indicate soils here might have reached to equilibrium levels due to higher land use intensity. Topographically higher lands (HL and MHL), due to less of inundation, had higher cropping intensities and lower SOC’s than lower lands (MLL and LL), which had lower cropping intensities, as they remain inundated for longer periods of time. The findings clearly demonstrate the intrinsic influence of land inundation in driving cropping intensity, land management practices and SOC levels.
Creativity is one of those tropes that seems to do the rounds regularly in, well, creative circles. Almost by definition, it is levelled at the arts, in part because its base definition is along the lines of the ability to create. Withinthis context, cartography is well-poised because any map requires the cartographer to create a new, unrealised, graphic product.
OPEN ACCESS EPRINT: Demystifying academics to enhance university-business collaborations in environmental science
John K. Hillier, Geoffrey R. Saville, Mike J. Smith, Alister J. Scott, Emma K. Raven, Jonathon Gascoigne, Louise J. Slater, Nevil Quinn, Andreas Tsanakas, Claire Souch, Gregor C. Leckebusch, Neil Macdonald, Alice M. Milner, Jennifer Loxton13, Rebecca Wilebore, Alexandra Collins, Colin MacKechnie, Jaqui Tweddle, Sarah Moller, MacKenzie Dove, Harry Langford, and Jim Craig (2019)
challenge posed by a heavily time-constrained culture; specifically, tension exists between opportunities presented by working with business and non-optional duties (e.g. administration and teaching). Thus, to justify the time to work with business, such work must inspire curiosity and facilitate future novel science in order to mitigate its conflict with the overriding imperative for academics to publish. It must also provide evidence of real-world changes (i.e. impact), and ideally other reportable outcomes (e.g. official status as a business’ advisor), to feed back into the scientist’s performance appraisals. Indicatively, amid 20-50 key duties, typical full-time scientists may be able to free up to 0.5 day per week for work with business. Thus specific, pragmatic actions, including short-term and time-efficient steps, are proposed in a “user guide” to help initiate and nurture a long-term collaboration between an early- to mid-career environmental scientist and a practitioner in the insurance sector. These actions are mapped back to a tailored typology of impact and a newly created representative set of appraisal criteria to explain how they may be effective, mutually beneficial and overcome barriers. Throughout, the focus is on environmental science, with illustrative detail provided through the example of natural hazard risk modelling in the insurance sector. However, a new conceptual model of academics’ behaviour is developed, fusing perspectives from literature on academics’ motivations and performance assessment, which we propose is internationally applicable and transferable between sectors. Sector-specific details (e.g. list of relevant impacts and user guide) may serve as templates for how people may act differently to work more effectively together.
I’ve waxed lyrical about the Ricoh GR being a great UAV camera before - well the long awaited successor has been announced (but hasn’t yet landed) and summarised over at DPReview. The interesting aspects of the uprated specs are IIS (inbody image stabilisation), 24MP sensor and touchscreen. The resolution boost and IIS will be of significant interest to UAV users so it will be interesting to see how it performs out in the field.
An interesting talk from TEDxMileHighWomen. Worth a watch to get a short 10-min summary of some of the issues involved with publishing academic research - the comments are worth a look too.
As Erica Stone implies, she hasn’t got much experience in academic publishing and it unfortunately shows. There are some points well made, but there is and underlying naivety about the role of publishing, the cost, the requirements of universities and the amount of time academics have. As I noted in my editorial this year:
Academic publishing is a knowledge distribution and academic assessment system, partially funded by universities and research institutes.
To publish you have cross-subsidise, or go down an author or reader pays route - ironically (and perhaps to the chagrin of the OA camp), OA is currently costing the system more than a subscription model on an annual basis and probably on a pageview basis too. But, let’s keep the debate going!
The Ordnance Survey released their Code-Point Open product a few years ago that has the OSGB centroids of the unit postcodes. It’s very useful but is only points - if you want the postcodes areas as polygons then you need to license Code-Point with Polygons (snappily titled!). A number of people have derived unit postcode areas using Voronoi polygons including more recently Mike Spencer with some intro at his Scottish Snow site. It’s worth noting that Voronoi diagrams equally partition space between points and nothing more - they are not equivalent to unit postcodes (which can be arbitrary) but are a reasonable first guess. One dataset worth having for your arsenal of spatial data!
I was sad to see that Waldo Tobler passed away last month - a lifetime geoscientist he contributed huge amounts to computational cartography but will be best remember for the First Law of Geography. Some more details at GeoLounge and in the original paper.
However I love the CSISS Classic which was a tongue-in-cheek experiment with Peter Gould on geocoding. Read it because its wonderfully powerful way of showing students about geocoding. Hopefully we’ll see an anthology of his work in the not too distant future.
QGIS 3 is well and truly out now - download your copy here. And the good folks over at GIS Geography have put together a list of QGIS features that are in the new version. Some of the highlights include 3D (1), coordinate reference bounds (5), geopackage (7), background processing (8), new print composer (13), refined graphical modeler (25), but they are all worth taking a look at as it might just be a solution to the problem you have!