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GEOSTATS: Spherekit: new unix shareware for spatial data analysis

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  • Dubois Gregoire
    Greetings, I think this would be a good news to start 97. Best regards, Gregoire ... Spherekit Spherekit was developed at the NCGIA (National Center for
    Message 1 of 1 , Feb 3 11:31 AM
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      Greetings,

      I think this would be a good news to start 97.

      Best regards,


      Gregoire


      ----------------------------------------------

      Spherekit

      Spherekit was developed at the NCGIA (National Center for Geographic Information and Analysis)
      and at the University of California, Santa Barbara (UCSB). Developers include: Cort Willmott
      (University of Delaware), Rob Raskin (Jet Propulsion Laboratory), Chris Funk (NCGIA),
      Scott Webber (University of Delaware), and Mike Goodchild (NCGIA).

      The initial version has been released into the public domain in October 1996.

      Spherekit is an integrated toolkit for spatial interpolation and comparison of
      spatial interpolation algorithms. It is UNIX-based and includes a complete graphical
      user interface (GUI). It uses Generic Mapping Tools (GMT) for display of interpolated fields.


      The package features several unique capabilities:

      Large-scale interpolation

      Spherekit permits interpolation over continental or global scales because its computations
      are based upon spherical distances and orientations. Conventional interpolations are based upon planar
      projections of the earth, which produce distortions of some kind over large distances. In Spherekit,
      projections are applied only for display purposes, after the interpolation has been carried out in spherical
      geometry. The user can select from a wide range of interpolation algorithms and can experiment with
      any associated parameter settings.


      Smart interpolation

      Spherekit permits the user to incorporate knowledge or information about the processes that produced the
      spatial variations. This strategy, also known as "smart interpolation," is implemented through the
      interpolation of user-defined, derived variables. A simple equation editor is available to produce
      combinations of observation variables, and several nonlinear transforms are built-in. A digital elevation
      model (DEM) is included so that elevation can be treated consistently with other variables.


      Error analysis

      Error analysis is an integrated component of Spherekit. The performance of an interpolation
      method and its associated set of parameters is evaluated using cross-validation. The error at each
      observation point is defined as the difference between its actual value and its estimated value using
      the remaining n-1 points. The resulting error field can be displayed either at the data points or
      interpolated to a regular grid, to reduce any spatial biases. Error difference fields, comparing a pair
      of methods, can be easily displayed.

      The available Interpolation methods are

      Inverse distance weighting
      Triangulation
      Kriging
      Multiquadric
      Thin plate spline

      Spherekit is available for download by anonymous ftp from the NCGIA.

      Check the HOMEPAGE at http://www.ncgia.ucsb.edu/pubs/spherekit/main.html


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