A Global Grid Model Based on "Constant Area" Quadrilaterals
نویسندگان
چکیده
The WGS84 ellipsoid is tessellated using quadrilaterals of roughly the same size. The tessellation scheme is developed for the purpose of storing, distributing and analysing global as well as local digital terrain models. Compared with DTED, the new grid has a more uniform distribution of cell sizes. This equal area property of the tiles of the grid is an attractive characteristic in geostatistical and wavelet analysis of the terrain model.
منابع مشابه
A Concept for Creating, Storing, Updating and Delivering Variable Resolution Terrain Models
The NVRG/Sarepta is an implementation of a terrain model server based on a global variable resolution grid. Access to the system is through a web service, which makes it essentially platform independent. The grid tiles are quadrilaterals of nearly homogeneous size across the globe. Finer resolution levels are generated by regular subdivision. The terrain data is organized in a file structure th...
متن کاملk-Sets, Convex Quadrilaterals, and the Rectilinear Crossing Number of Kn
We use circular sequences to give an improved lower bound on the minimum number of (≤ k)– sets in a set of points in general position. We then use this to show that if S is a set of n points in general position, then the number (S) of convex quadrilaterals determined by the points in S is at least 0.37533 ` n 4 ́ + O(n). This in turn implies that the rectilinear crossing number cr(Kn) of the com...
متن کاملApplication of different inverse methods for combination of vS and vGPR data to estimate porosity and water saturation
Inverse problem is one of the most important problems in geophysics as model parameters can be estimated from the measured data directly using inverse techniques. In this paper, applying different inverse methods on integration of S-wave and GPR velocities are investigated for estimation of porosity and water saturation. A combination of linear and nonlinear inverse problems are solved. Linear ...
متن کاملAn Equal Area Quad-tree Global Discrete Grid Subdivision Algorithm Based on Latitude and Longitude Lines
In order to effectively solve the problems of global discrete grid in spatial data management and operations, a novel equal area quad-tree global discrete grid subdivision model based on latitude and longitude lines is proposed in this paper. Coding rules of grid cells, and geometric distortion calculation and analysis of the grid model are also given in the detailed subdivision process. The re...
متن کاملAre Bilinear Quadrilaterals Better Than Linear Triangles?
This paper compares the theoretical effectiveness of bilinear approximation over quadrilaterals with linear approximation over triangles. Anisotropic mesh transformation is used to generate asymptotically optimally efficient meshes for piecewise linear interpolation over triangles and bilinear interpolation over quadrilaterals. For approximating a convex function, although bilinear quadrilatera...
متن کامل