‘Co-designing’ services based on Earth Observation (EO) data has proven to be a successful way to overcome insufficiencies of different strategies employed by the EO experts to bridge the grand distance that separates them with potential users. Concurrently, we are witnessing the development of novel platforms designed to assist local authorities in policymaking based on EO. However, our understanding of the conditions that support a platform-based co-design remain unclear. We advance the possibility of new co design methods that conciliate two major challenges faced by platform designers: contextualizing the platform to demonstrate its usefulness and increasing the genericity of the platform components as to foster its generative potential. Approaching platforms as ‘data-use fit systems’, our attempt is to propose a framework for such a ‘co-design’ methods, enlightening retrofit mechanisms as a key lever to conciliate these two challenges. Based on a qualitative case study focused on the application of the DestinE platform to create a supersite for the city of Marseille, our objective lies in proposing a sustainable toolkit to support these new co-design methods.

We consider a Hermite interpolation problem for a 3D curve where the functional to be minimized is defined as the integral of squared norm of the third parametric derivative, subject to G2 continuity constraints at the end points. The first order necessary optimality condition of the variational problem leads to a parametric transition curve with quintic polynomials. The determination of coefficients is given by a polynomial system with 2 unknowns. Stationary points correspond to positive roots of the resultant which is a degree 9 polynomial. Although the formulated variational problem is non-convex, the proposed approach leads to the global solution, which can be computed in a reliable and fast manner.

The National Aeronautics and Space Administration (NASA) of the USA is making available to anyone worldwide maps of ground albedo parameters that are derived from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument. The first parameter fiso describes the isotropic part of the bidirectional reflectance distribution function (BRDF); the two other parameters fvol and fgeo are linked to the viewing and illuminating geometry and describe the anisotropic part of the BRDF. These maps exhibit missing values. This communication describes a series of 12 monthly maps of the BRDF parameters with no missing values available on the Web. In addition, a method for computing the ground albedo is proposed that does not require the a priori knowledge of the ratio of the direct to the global irradiance.

Multispectral (MS) images provided by Earth observation satellites have generally a poor spatial resolution while panchromatic images (PAN) exhibit a spatial resolution two or four times better. Data fusion is a means to synthesize MS images at higher spatial resolution than original by exploiting the high spatial resolution of the PAN. This process is often called pansharpening. The synthesis property states that the synthesized MS images should be as close as possible to those that would have been acquired by the corresponding sensors if they had this high resolution. The methods based on the concept Amélioration de la Résolution Spatiale par Injection de Structures (ARSIS) are able to deliver synthesized images with good spectral quality but whose geometrical quality can still be improved. We propose a more precise definition of the synthesis property in terms of geometry. Then, we present a method that takes explicitly into account the difference in modulation transfer function (MTF) between PAN and MS in the fusion process. This method is applied to an existing ARSIS-based fusion method, i.e., A trou wavelet transform-model 3. Simulated images of the sensors Pleiades and SPOT-5 are used to illustrate the performances of the approach. Although this paper is limited in methods and data, we observe a better restitution of the geometry and an improvement in all indices classically used in quality budget in pansharpening. We present also a means to assess the respect of the synthesis property from an MTF point of view.

The input pupil of interferometry-based observation instruments is necessarily segmented. Since the Optical Transfer Function (OTF) of any optical instrument observing in incoherent light is the auto-correlation of its input pupil, it follows that any combination of size and position of each pupil segment will have an impact on the OTF behavior and therefore on the quality of the output image. The goal of this study is to propose computational geometry methods allowing to find pupil geometries leading to an isotropic OTF support with a controlled redundancy of viewed spatial frequencies in the Fourier domain.