The first taste of Ne3 (netree) (at IEMSs in Toulouse)

We had this presentation, this morning at IEMSs, about some of the many lines of work where Francesco Serafin (his blog here) is developing his Ph.D research. The origin of the work is that modelling basins is to model hillslopes (or Hydrologic Response Units, HRUs) connected by a river network. Most of what happens in HRUs is independent from what happens in the others. Some instead is aggregated by river network. So why do not use this natural structure to organise modelling and processes (and send them in parallel, when possible, using the tree structure) ?

Actually this can grow more, since many systems (a plant, ecological interactions, hydrological interactions), can be seen described over a graph of interactions. So the Ne3 can become a more general way to investigate natural systems. However, you can enjoy the presentation, by clicking on the figure above.  Ne3 source code written so far in on Github.

Pfafstetter Numbering and the organisation of river networks

We just have accepted a paper related to the topological ordering we use inside our model JGrass-NewAGE.  This ordering derives is a generalisation of the Pfafstetter algorithm.
Once understood, it can be observed that this Pfafstetter ordering can be used to drive, for instance parallel execution of operations. But this is another story. We actually use to orderly process the basin partition in JGrass-NewAGE modules. The paper, entitled "Digital watershed partition within the NewAGE-Jgrass system" by Formetta et al.  can be downloaded from here.

Related topics are covered in posts of the Horton Machine, and particularly in the book Chapter written early this year for the British Gemorphological society. Abera's blog also contains a related post that can clarify some other issues. 

A Geomorphological Assessment of Constable Landscapes

I took this post from the River Management Blog, and the post is by Simon Dixon. John Constable is one the greatest English landscape painter, and, in the words of the blog authors, contributed very much to the idea of what a natural landscape is. However, reading the post, you can realize that his paintings portrait not so natural landscapes.

Click, as usual on the painting to jump on the post.

Rivers in transitions

An editorial of Nature Geoscience to read.

"Rivers affect landscape structure and function to a much greater extent than might be expected from the fraction of the Earth's surface they cover. Rivers redistribute material as they flow, carving out canyons and building new land offshore. These morphological consequences of river flow are evident in any topographic map of the Earth's surface. ..."

Other links are also available at the page.

Browsing the same number also a commentary is available on the role of rivers, and a paper on river drainage patterns in New Zealand.

From the work "the thousand rivers” (i mille fiumi) by Arrigo Boetti and Anna-marie Sauzeau-Boetti

classification by order of magnitude is the most common method for classifying information relative to a certain category, in the case of rivers, size can be understood to the power of one, two, or three, that is, it can be expressed in km, km2, or km3 (length, catchment area, or discharge), the length criterion is the most arbitrary and naive but still the most widespread, and yet it is impossible to measure the length of a river for the thousand and more perplexities that its fluid nature brings up (because of its meanders and its passage through lakes, because of its ramifications around islands or its movements in the delta areas, because of man’s intervention along its course, because of the elusive boundaries between fresh water and salt water...) many rivers have never been measured because their banks and waters are inaccessible, even the water spirits sympathize at times with the flora and the fauna in order to keep men away, as a consequence some rivers flow without name, unnamed because of their untouched nature, or unnamable because of human aversion (some months ago a pilot flying low over the brazilian forest discovered a “new” tributary of the amazon river). other rivers cannot be measured, instead, because they have a name, a casual name given to them by men (a single name along its entire course when the river, navigable, becomes means of human communication; different names when the river, formidable, visits isolated human groups); now the entity of a river can be established either with reference to its name (trail of the human adventure), or with reference to its hydrographic integrity (the adventure of the water from the remotest source point to the sea, independently of the names assigned to the various stretches), the problem is that the two adventures rarely coincide, usually the adventure of the explorer is against the current, starting from the sea; the adventure of the water, on the other hand, finishes there, the explorer going upstream must play heads or tails at every fork, because upstream of every confluence everything rarefies: the water, sometimes the air, but always one’s certainty, while the river that descends towards the sea gradually condenses its waters and the certainty of its inevitable path, who can say whether it is better to follow man or the water? the water, say the modern geographers, objective and humble, and so the begin to recompose the identity of the rivers, an example: the mississippi of new orleans is not the extension of the mississippi that rises from lake itasca in minnesota, as they teach at school, but of a stream that rises in western montana with the name jefferson red rock and then becomes the mississippi-missouri in st louis, the number of kilometres upstream is greater on the missouri side, but in fact this “scientific” method is applied only to the large and prestigious rivers, those likely to compete for records of length, the methodological rethinking is not wasted on minor rivers (less than 800km) which continue to be called, and measured, only according to their given name, even if, where there are two source course (with two other given names), the longer of the two could be rightly included in the main course, the current classification reflects this double standard, this follows the laws of water and the laws of men, because that is how the relevant information is given, in short, it reflects the biased game of information rather than the fluid life of water, this classification was began in 1970 and ended in 1973, some data were transcribed from famous publications, numerous data were elaborated from material supplied non-european geographic institution, governments, universities, private research centres, and individual accademics from all over the world, this convergence of documentation constitutes the the substance and the meaning of the work, the innumerable asterisks contained in these thousand record cards pose innumerable doubts and contrast with the rigid classification method, the partialness of the existing information, the linguistic problems associated with their identity, and the irremediably elusive nature of water all mean that this classification, like all those that proceeded it or that will follow, will always be provisional and illusionary

Anne-marie Sauzeau-Boetti

(TN the text is published without capital letters)
(translation by Joseph Tomasi)

A comment on the opera can be found, for instance, here, at Moma site.