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by Charles L. Mohler

COMPOSE is a data management program which checks errors, edits and formats data for use by other programs in the Cornell Ecology Programs series. As with all programs in the CEP series, COMPOSE is designed to operate on a two dimensional data array. Typically such an array will consist of abundance values of species measured at a number of sample locations. Occasionally one may have data of three or more dimensions. In ecological applications these are commonly encountered when several attributes are measured on each species in several samples, or when species are sampled repeatedly at several locations. COMPOSE has editing capabilities which can reduce such three dimensional data to a two dimensional structure suitable for processing with the other programs.

COMPOSE accepts data in many varieties of two basic formats: Full Matrix and Condensed. These are ASCII text files with data in columns such as a LotusTM .PRN file, dBaseTM or FoxBaseTM SDF file. COMPOSE converts these to the restricted condensed format which is acceptable to all programs in the Cornell Ecology Programs MS-DOSTM microcomputer package. In addition to producing the edited and reformatted data matrix, the program produces a session listing which echoes all discourse appearing on the screen, as well as listing useful information about the data.

COMPOSE has a variety of editing functions. It automatically adds together all occurrences of a species within each sample. At the users request it will merge any number of data sets. It will eliminate species and samples at the users request. It can add together species and assign a new name to the resulting entity (if, for example, you want to merge species within a genus), and it can form composite samples from groups of samples. The program can also apply a variety of statistical and ecological transformations to the data.

COMPOSE checks for and flags errors in the data and accompanying lists of names and parameters. For this reason we recommend that you run data sets through COMPOSE even if they have been entered in a restricted condensed format and no editing is desired. The Cornell Ecology Programs are quite easy to use, but in the interest of maximizing array space for analyses, they do minimal checking of the structure of the data set at run time. Most of the problems people encounter with the programs involve improperly structured data sets. COMPOSE is a valuable tool for avoiding such problems.

The MS-DOSTM executable module is dimensioned for 1,000 Species, 1,200 Samples, 27,000 non-zero array elements.

COMPOSE is included with CEP-PC . It is also available separately as:

n CLM-CMel COMPOSE<SUP><SMALL>TM</SMALL></SUP> program for data preparation

Dr. Richard E. Furnas
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