# Tesseroids: forward modeling in spherical coordinates¶

A collection of command-line programs for modeling the gravitational potential, acceleration, and gradient tensor. Tesseroids supports models and computation grids in Cartesian and spherical coordinates.

Developed by Leonardo Uieda in cooperation with Carla Braitenberg.

Official site: http://tesseroids.leouieda.com

Source code: https://github.com/leouieda/tesseroids

Latest release: v1.2.1 (doi:10.5281/zenodo.582366)

Note

Tesseroids is research software. Please consider citing it in your publications if you use it for your research.

Warning

See the list of known issues for things you should be aware of.

The geometric element used in the modeling processes is a spherical prism, also called a tesseroid. Tesseroids also contains programs for modeling using right rectangular prisms, both in Cartesian and spherical coordinates.

View of a tesseroid (spherical prism) in a geocentric coordinate system. Original image (licensed CC-BY) at doi:10.6084/m9.figshare.1495521.

## Getting started¶

Take a look at the examples in the Cookbook. They contain scripts that run Tesseroids and some Python code to plot the results.

If you’re the kind of person who likes to see the equations (who doesn’t?), see the Theoretical background and the references cited there.

For a more detailed description of the software, options, and conventions used, see the usage instructions.

Also, all programs accept the -h flag to print the instructions for using that particular program. For example:

\$ tessgrd -h
Usage: tessgrd [PARAMS] [OPTIONS]

Make a regular grid of points.

All units either SI or degrees!

Output:
Printed to standard output (stdout) in the format:
lon1    lat1    height
lon2    lat1    height
...     ...     ...
lonNLON lat1    height
lon1    lat2    height
...     ...     ...
...     ...     ...
lonNLON latNLAT height

the top of the output

Parameters:
-r           W/E/S/N: Bounding region of the grid.
-b           NLON/NLAT: Number of grid points in the
longitudinal and latitudinal directions.
-z           HEIGHT: Height of the grid with respect to the
-h           Print instructions.
--version    Print version and license information.

Options:
-v           Enable verbose printing to stderr.
-lFILENAME   Print log messages to file FILENAME.

Part of the Tesseroids package.
Project site: <http://fatiando.org/software/tesseroids>