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New series of books “Land Surface Remote Sensing”

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We are pleased to inform you of the publication of a series of books entitled “Land Surface Remote Sensing” with ISTE-Elsevier editors (September, 2016):

  •  Optical Remote Sensing of Land Surfaces
  • Microwave Remote Sensing of Land Surfaces
  • Land Surface Remote Sensing in Agriculture and Forest
  • Land Surface Remote Sensing in Continental Hydrology
  • Land Surface Remote Sensing in Urban and Coastal Areas
  • Land Surface Remote Sensing: Environment and Risks

This series is designed for those who wish to discover or intensify their knowledge of remote sensing applied to continental surfaces. Each book of this series contains a dozen chapters.

This series is the result of a rich collaboration with world-class researchers in different topics including Canadians co-authors. The editors are the two researchers Nicolas Baghdadi (PhD) and Mehrez Zribi (PhD).

More details can be found at:

(1) http://www.iste.co.uk/index.php?searchtext=baghdadi&ACTION=Search&cat=&ACTION=Search

or

(2) http://store.elsevier.com/searchResults.jsp?_sbterm=&_requestid=4227446 (tapping baghdadi ou zribi)

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Do you know the WikiGIS concept ?

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Read this most recent paper to know more about this emerging concept.

Towards a Conceptual Framework for WikiGIS

Wided Batita, Stéphane Roche, Yvan Bédard and Claude Caron

Abstract
As an emerging complex concept, GeoDesign requires an innovative theoretical basis, tools, supports and practices. For this reason, we propose a new concept, “WikiGIS”, designed to answer some dimensions of the GeoDesign process. WikiGIS focuses on the needs of GeoDesign, but we leave the door open for future improvement when tested in other areas that may have additional needs. WikiGIS is built on Web 2.0 technologies—and primarily on wiki—to manage the tracking of participants’ editing (i.e., managing the contributions history). It also offers GIS functions for geoprocessing and a design-based approach for sketching proposals. One of the main strengths of WikiGIS is its ability to manage the traceability of contributions with an easy and dynamical access, data quality and deltification. The core of this paper consists of presenting a conceptual framework for WikiGIS using UML diagrams. A user interface is presented later to show how our WikiGIS proposal works. This interface is simply a means to illustrate the concepts underlying WikiGIS.

[View the full paper]

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Combining GPS/GLONASS to Improve Precise Point Positioning

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This paper presents a new method that combines GPS/GLONASS measurements and uses fixed GPS ambiguity to improve precision and performance.

Abstract

Precise point positioning (PPP) technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs) are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA) in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM) is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF). All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF.

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