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What is PC-ORD For?
PC-ORD is a Windows program for multivariate analysis of ecological data
entered in spreadsheets. The terminology in the software is tailored for ecologists.
We emphasize nonparametric tools, graphical representation, and randomization
tests for analysis of community data. In addition to utilities for transforming
data and managing fi les, PC-ORD offers many ordination and classifi cation
techniques not available in major statistical packages including: CCA, DCA, MRPP,
perMANOVA, two-way clustering, TWINSPAN, Beals smoothing, diversity indices,
species lists, Mantel test, many ordination overlay methods (quantitative, symbol-
coding, color-coding, grid, joint plot, biplot, successional vector), various rotation
methods, 3D ordination graphics, indicator species analysis, Bray-Curtis ordination,
city-block distance measures, species-area curves, tree data summaries, publication-
quality dendrograms, and autopilot NMS.
Very large data sets can be analyzed. Most operations accept a matrix up to
32,000 rows or 32,000 columns and up to 536,848,900 matrix elements, provided
that your computer has adequate memory.
Virtually any multivariate data set consisting of a set of entities, each with a
number of measured attributes, is adaptable to PC-ORD. In community ecology,
the fi rst matrix will often contain species abundance data in a set of samples. The
possible formats for entering these data can be found in Data Preparation in the
software help system. In addition to this main matrix, a second matrix, often
containing environmental data, can be entered for analysis of its relationship to
the fi rst matrix. The inclusion of this second matrix greatly enriches the system’s
analytical capabilities. Both matrices are displayed in PC-ORD in fi le viewing
windows.
