VISUALISATION / GRAPHICS
Igor Pro 5.0
21 September 2006
Reviewed by Felix Grant
Depending on your sense of humour and your opinion of old Frankenstein films, Igor may seem either strange or appropriate as the name of a scientist’s graphing assistant. Either way, it’s a name worth remembering. Upfront, Igor Pro 5.0 is a technical graphics program with all that you would expect in that category: publication quality output for a range of graphs, charts, and so on, with some accompanying analytic capacity. Look beyond that, and it has a number of less usual aspects and features.
To begin at the beginning, Igor (unlike most such packages) does not primarily view data as Cartesian points but as waves. A wave is, in conventional statistical terms, a variable whose y values are given against a constant x interval scaled by the user. Cartesian coördinate pairs are accommodated by assigning each axis to one wave in a pair – an x wave and a y wave – whose amplitude values against the shared displacement provide successive points.
Multidimensional analysis facilities, from wave arithmetic through specialised fast Fourier transforms and matrix operations, extend the simple amplitude structure. Rows in the table representation are joined by columns, layers and 'chunks' to define scaled wave points in terms of x, y, z and t coördinates.
The Igor wave (or set of waves) is a conceptual object with two manifestations: the table and the graph. Together with supporting elements (text, illustrations, etc) graphs and tables are presented in page layouts, and the collective entity containing all four object types is dubbed an experiment.
Display graphic options are rich and extensive, taking in not only the usual charts but surfaces, volumes, cross sections and a range or map projections including equal area options. Analysis adds to the usual repertoire such features as numerical calculus, curve and peak fits. The waveform orientation means that Igor, while offering generic capability, has particular strengths in areas such as digital signal processing. The gamut of tools is considerably more extensive than would normally be expected from a technical graphics product. I’ve been particularly interested, during the review period, in the range of image processing competence with numerous transforms, morphological operations, and convolution filtering.
Compared to packages designed with one eye on business use by nonmathematical users, full exploitation of Igor also demands commitment, attention to detail and understanding of the goals and processes being represented. There is a windowed graphical user interface which allows rapid access to useful ranges of power, but maximum control and reach requires direct use of the underlying control language – either at the command line or through stored procedures.
Various supplementary support is available for expansion and extensive customisation through external modules in C, direct data acquisition from National Instruments multifunction DAQ boards, and finite impulse response filters. Further hardware and software options are available from third-party suppliers including, for example, camera control from software.
It all works quickly, efficiently and well, it is available on both Windows and Mac, and its metaphors are particularly suited to many areas of scientific activity. A 30-day trial version is available, fully functional apart from disabled saves and print output watermarking.