Development

 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.

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.

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.