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Department of Theoretical Geodesy

 

GrafLab (GRAvity Field LABoratory)

GrafLab is a MATLAB-based graphical user interface program for computing functionals of the geopotential up to ultra-high degrees and orders, which allows:
- evaluation of 38 functionals of the geopotential up to ultra-high degrees and orders,
- evaluation of commission error of 26 functionals using full variance-covariance matrix of spherical harmonic coefficients,
- depiction of the computed data on a map.

If you wish to receive notifications of the latest releases of GrafLab via email, please send an email to Blažej Bucha (the address can be found at the beginning of the source code) with the subject of the email: GrafLab notifications – signing in. If you no longer wish to receive these emails, please send us an email with the subject: GrafLab notifications – signing off.

 

isGrafLab (Irregular Surface GRAvity Field LABoratory)

isGrafLab is a modified version of GrafLab that allows accurate and fast computation of functionals of the geopotential at dense grids on irregular surfaces such as the Earth's surface. It employs the highly efficient lumped coefficients approach for surface spherical harmonic synthesis of the functionals and their radial derivatives at regular surfaces (sphere or ellipsoid of revolution), and the Taylor series expansions to continue the functionals to the irregular surface. All the other options available in GrafLab, such as the possibility to use three different approaches to compute the fully normalized associated Legendre functions, the graphical user interface or data plotting, are also available in the new software.

  • source code (version 2.1.2)
  • input and output data for the test computation
  • user manual
  • Bucha, B., Janák, J., 2014. A MATLAB-based graphical user interface program for computing functionals of the geopotential up to ultra-high degrees and orders: Efficient computation at irregular surfaces. Computers & Geosciences 66, 219-227, http://dx.doi.org/10.1016/j.cageo.2014.02.005.
  • list of changes in isGrafLab (updated April 5, 2019)

If you wish to receive notifications of the latest releases of isGrafLab via email, please send an email to Blažej Bucha (the address can be found at the beginning of the source code) with the subject of the email: isGrafLab notifications – signing in. If you no longer wish to receive these emails, please send us an email with the subject: isGrafLab notifications – signing off.

 

Other codes and output products by Blažej Bucha

This page offers computer codes and output products from some other research papers by Blažej Bucha. Provided are Matlab-based software packages:

  • to perform ultra-high-degree surface spherical harmonic analysis,
  • to compute Molodensky’s truncation coefficients for cap-modified spectral gravity forward modelling.

The output products encompass:

  • global GOCE-only spherical harmonic gravity field models derived from the satellite’s kinematic orbit,
  • divergence-free spherical harmonic models of the gravity field implied by the Moon’s topographic masses,
  • pre-computed ready-to-use Molodensky’s truncation coefficients for ultra-high-degree cap-modified spectral gravity forward modelling.