This paper presents a parallel implementation of the discrete Legendre transform using SIMD machines, MasPar MP-1 and MP-2. Laguerre, Hermite, and binomial transforms can be implemented in a similar manner using some ...
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This paper presents a parallel implementation of the discrete Legendre transform using SIMD machines, MasPar MP-1 and MP-2. Laguerre, Hermite, and binomial transforms can be implemented in a similar manner using some of the computations required to compute the discrete Legendre transform. The time required to compute the discrete Legendre transform vs. number of points for an MP-2 machine is included.
A new method for visualizing data on a globe or unit sphere is described. Information that is distributed over a sphere—global oceanographic or geographic measurements, all‐sky astronomy observations, or any quantit...
A new method for visualizing data on a globe or unit sphere is described. Information that is distributed over a sphere—global oceanographic or geographic measurements, all‐sky astronomy observations, or any quantities that are best represented in spherical coordinates—can benefit from this technique. Retaining a better sense of the geometry and information content of the data, 3‐D graphics can provide an unobstructed view of the entire sphere, without undo deformation of its surface area. A ‘‘parametrized ray trace’’ produces look‐up tables (LUTs) that can be used for all visualizations. The ray trace result shows one or more spheres with the data as a texture map and three reflecting rectangles that ‘‘mirror’’ the far sides of the sphere(s) into view. The LUTs need only be created once, and a general purpose computer will do. No special purpose hardware is required beyond a PC or workstation that supports color. Examples from astronomical and geophysical datasets, which are commonly displayed with an area deforming (2‐D) projection, are presented.
作者：
LOWREY, BECentral Data Services Facility
Code 633 National Space Science Data Center Space Data and Computing Division Goddard Space Flight Center Greenbelt MD 20771 U.S.A.
Symmetric features, both natural and man-made, exist on earth and are visible in spacedata. This paper closely examines one circularly symmetric object, the Robert F. Kennedy stadium in Washington, DC, which is conta...
Symmetric features, both natural and man-made, exist on earth and are visible in spacedata. This paper closely examines one circularly symmetric object, the Robert F. Kennedy stadium in Washington, DC, which is contained in a Landsat-4 Thematic Mapper image. The effect of the space measurement on the appearance of the feature varies according to the band of the image. The human perception of the data is affected by the band and also by the magnification and context of the feature. The differences in interpretability of one object demonstrate the nature of the challenges involved in achieving computer vision. The future computing systems and related developments that may enable a machine to “understand” a symmetric object are described.
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