Quantifying the impact of land use on the nitrogen cycle

Session Type: 
Sylvain Maillard, la Tour du Valat
Alain Sandoz PhD
Jean-Luc Boudenne PhD

 Better knowledge of the impacts of large scale land use on water quality are needed to act on urbanism and country planning at the scale of a global watershed, as outlined in the European Water and Wetlands law.

Nitrogen is one of the most important pollutants in surface waters and comes from different sources. In this study, remote sensing techniques and Geographical Information Systems have been used successfully to monitor and quantify the sources of Nitrogen on the scale of a global watershed.

The surface water selected for the present study is a French River –the Durance- and its surroundings, located in the South-East of France and running through Provence from the Alps to the Rhône River. The watershed area is 14 000 km2 and covers very different landscapes from high mountains to Mediterranean forests, and encounters various human activities.
Data have been extracted from two main databases: i) the archive database provided by the USGS which gives us open access to 25 years of Landsat-5 data, ii) A French database reporting analyses of water quality (SANDRE), available from the French Water Agency web portal, which allows us to freely access 40 years’ data.

A supervised classification was applied on the satellite imagery to produce land use maps with a better accuracy than the Corine Landcover datas. The sub-watershed of each sampling station was computed using its geographical location and the ASTER Digital Elevation Model, this allows the calculation of land use statistics for each sub-watershed.
In the SANDRE database, total nitrogen is available as the sum of Kjeldahl nitrogen, ammonium, nitrates and nitrites. The concentrations of the different species of nitrogen were averaged by sampling station and year.

Speaker Bio: 

I am a phD student at the University of Provence (France), working at the research centre for the conservation of Mediterranean wetlands, the Tour du valat, located in the Camargue (France)

VisREACHER: A FOSS Environmental Decision Support Systems for Odense River Basin in Demark

Session Type: 
Msc Xuan Zhu Ms
Prof Arthur Mynett Mr
Ann Van Griensven
Yunqing Xuan

Environmental process researches express the complex model results by using complicated style, e.g. functions, tables, diagraphs and so on. Furthermore, running those models can take large amount of time. These will add the difficulties of decision support process especially when the stakeholders are not experts of this disciplinary. Therefore, the user interface design for such a system is very important which should maintain the scientific model structure and also simplify the interaction with models. Meanwhile, as the decision support system can be used to evaluate the effects of different alternatives, the user interface also should have the ability to render the new scenarios as soon as possible. In this project, we developed one prototype of WebDSS system, named VisREACHER, based on several open source programs: Mapserver, Openlayers, GeoEXT and PostGIS. We put our original water quality model results into a Bayersian Network model to generate the possibilities of future scenarios and then put those possibilities outputs into the postGIS spatial database in order to link with the entire river basin’s topology. After that, we create several vector layers to link with the database which are clickable and editable. By this structure, users can interact with the map-based user interface and input their own assumptions with quick responses. In this way of representing the models, users can get the spatial information quickly and try their own alternatives without running the original water quality model again. These FOSS programs are flexible and powerful in representing spatial information over the map layers. In this paper, Firstly, we will analysis the user requirements of our working package. Secondly, the concept design of this web-based application is given. Thirdly, the technique details are described in following section. Then, the preliminary results are represented. Last but not least, several conclusions and comments are revealed.

Speaker Bio: 

Backgroud is computer science, now is phd student in Hydroinformatics. Research topic is Data visualization in Decision Support System 

A Vivid Relic Under Rapid Transformation

Session Type: 
Dr Thomas Knudsen, National Survey and Cadastre
Dr Simon Kokkendorff
Dr. Karsten Engsager
Dr. Karsten Bormann

KMSTR, the transformation system of the Danish National Survey and Cadastre (KMS), has served as the official tool for transformation between Danish map projections and horizontal and vertical datums for half a century. The system originated as a fairly simple implementation of a few conformal mappings, using one of the first compilers for the Algol-60 language. But it has evolved dramatically since then and survived through a range of three programming languages (Algol, Fortran, C), and a large number of operating systems and machine architectures.

Today, in addition to a large number of map projections, KMSTR supports a range of datum shift operations, implemented using either Molodensky transforms, high order polynomials, or NADCON style grid interpolations. KMSTR also includes support for time varying transformations based on plate tectonic motion models, for deriving the proper transformation between a global datum (e.g. ITRF89) and regional, plate fixed reference systems (such as ETRS89) at different epochs.

Recently the extended transverse mercator implementation of KMSTR was included in proj, the leading open source projection package. This is the first step towards making KMSTR more interoperable with other open source projection and transformation packages. From a KMSTR point of view this is highly desirable, since closer relations to proj and other open source projects will facilitate maintenance and development of KMSTR, and will help keeping it in line with the state of the art in geospatial software.

Speaker Bio: 

Thomas Knudsen, PhD, is a geodesist and senior adviser at the Danish National Survey and Cadastre, where his primary focus is on geodetic software tools.

A Fast Search Mechanism for Multiple Raster Layers in MapWindow Open Source GIS

Session Type: 
Mr Ahmad Aburizaiza, George Mason University
Dr Matthew Rice
Mr William Hammill

GIS raster data is a representation of cells or pixels arranged in rows and columns, where each cell signifies an attribute value representing different data types, such as slope, aspect, elevation, or temperature. Identifying and selecting the cells of a specific attribute value in the GIS programming world can be done fast in a single GIS raster layer. A problem might rise when the GIS programmer attempts to select a combination of multi values in exact cell locations in multi raster layers on top of each other. The more raster layers included for search, the longer time needed to obtain results and the more space needed for storage. This paper represents an innovated methodology in GIS programming, using the MapWindow open source GIS standalone development paradigm, to improve the searching speed for a distinct composite of multi values of identical cell locations in multi raster layers.The paper explains the development evolvement through four different approaches of searching multi raster layers. Each approach is an advancement of the previous approach in terms of speed and storage capacity. A timer tool was developed to calculate the mean time of running thirteen different queries against a small multi raster dataset and a large one, using the first basic approach and the fourth fastest approach. The results of the timer tool represents a significant improvement of searching speed, approximately twelve times faster. In addition, statistical analysis testing was applied to generate the percentage of agreement between the results of approaches one and four.

Geographic Reference Interface For Internet Networks

Session Type: 
Jan Kolar PhD, Grifinor Project

Geographic Reference Interface For Internet Networks (GRIFIN) is an experimental platform for exchanging spatio-temporal objects designed since 2005 primarily by Jan Kolar.

The goal of this effort is to consolidate research on next generation geographic systems, by the project participants as well as others, through designing a platform that could form a common core for research.

The purpose of the platform is to publish and exchange geo-referenced objects.

The term “object” here refers to a particular form for geo-related content that allows non-specialists to explore the objects in a digital representation of space-time, but also allows specialists to use instantly new, variable object-models.

Therefore it facilitates sharing and improvement of the models.
The platform design can provide a public Internet service, which allows for non-binding use by any user of the network in a similar manner as the Electronic mail, FTP or the Web services.

The properties of the service’s design address several research and development subjects.

The key ones are: globally ordered content, decentralization, interoperable and programmable content, and visualization.
These properties have been achieved using a number of scientific and engineering concepts of which the most important are: geospatial indexing, object oriented programming, terrestrial reference frame, managed code, and 3-D computer graphics.
The article provides an overview of the main aspects behind these concepts and how they were used in the design and development of the new service.

From the design point of view it is important to recognize that some of these concepts are relevant only for a specific property.
For example the concepts of 3-D computer graphics were almost exclusively applied for the support of visual representation of the content.

Other concepts, in contrast, are relevant for several of the listed properties.

Speaker Bio: 

With M.Sc. degree from Czech Technical University in Prague and Ph.D. from Aalborg University in Denmark, Jan is currently working as a consultant in geoinformatics.

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