GNU units converts quantities expressed in various systems of measurement to their equivalents in other systems of measurement. Like many similar programs, it can handle multiplicative scale changes. It can also handle nonlinear conversions such as Fahrenheit to Celsius, and it can perform conversions from and to sums of units, such as converting between feet plus inches and meters. Beyond simple unit conversions, units can be used as a general-purpose scientific calculator which keeps track of units in its calculations. You can form arbitrary complex mathematical expressions of dimensions including sums, products, quotients, powers, and even roots of dimensions. In this way, you can ensure accuracy and dimensional consistency when working with long expressions which involve many different units which may combine in complex ways. The units are defined in an extensive, well-annotated data file which defines over 2,500 units. You can also provide your own file to supplement or replace the standard file.
MathGL is a library for making high-quality scientific graphics under Linux and Windows, fast data plotting and handling of large data arrays, working in window and console modes, and easily embedding into other programs. It has more than 40 general types of graphics for 1d, 2d, and 3d data arrays. It can export graphics to raster and vector (EPS or SVG) formats. It has an OpenGL interface and can be used from console programs. It has functions for data handling and MGL language scripting for simplification of data plotting. It has several types of transparency and smoothed lightning, vector fonts and TeX-like formula drawing, an arbitrary curvilinear coordinate system, and many other useful things.
graphviz is a set of graph drawing tools and libraries. It supports hierarchical and mass-spring drawings; although the tools are scalable, their emphasis is on making very good drawings of reasonably-sized graphs. Package components include batch layout filters and interactive editors for X11, Java, and a TCL/tk extension. The batch filters can be configured as a web visualization service (using GIF and click-maps). Typical applications include display of finite state machines, software diagrams, database schemas, and communication networks.
FFTW is a fast C FFT library. It includes complex, real, symmetric, multidimensional, and parallel transforms, and can handle arbitrary array sizes efficiently.It is typically faster than other freely available FFT implementations, and is even competitive with vendor-tuned libraries (benchmarks are available at the homepage). To achieve this performance, it uses novel code generation and runtime self optimization techniques (along with many other tricks).
INDI is an instrument-neutral distributed interface control protocol that aims to provide backend driver support and automation for a wide range of astronomical devices (telescopes, focusers, CCDs, etc.). Current supported devices include many telescopes, CCDs, filter wheels, focusers, and video cams. INDI is used in popular astronomy suites like Xephem, KStars, DCD, and Cartes Du Ciel.
Orfeo Toolbox (OTB) is a high resolution remote sensing image processing library. It contains a set of algorithmic components which allow the user to capitalize on methodological know how, and therefore use an incremental approach to profit from the results of methodological research. OTB is made of a set of basic elements (a C++ class API) and utilities (independent programs built upon the base API).