Creating and editing data sets

18

cursor in the lower right hand column will add a new column. To add a new row, press

the Insert key. A row will be inserted below that currently selected. Please note, if the

text within a cell is selected (it will usually appear blue) pressing the Insert key will

not work. Simply click on the cell again to select the cell, rather than the text, and

insert will be activated. Use the Delete key to remove a row.

4.5

Editing existing data

The raw data grid can be edited by using the mouse to click on a cell to select it and

typing in a new value. Changes made to the raw data are transferred to the working

data by first selecting the working data tab and then selecting Revert to raw and

clicking on the Submit button. These changes will not alter a saved file until

File|Save is used. ECOM will use the working grid thus created for all subsequent

calculations. Note that output windows will not show calculations using the edited

data until the methods have been re run by selecting them in the normal fashion. The

working data grid can also be edited. Changes made to the working grid will not be

transferred to the raw data grid. Transformed or otherwise changed working data can

be saved as a new data set using File|Save as.

4.6

Saving edited data or creating a new data file

When File|Exit is selected, if a data set has been altered in any way, but not saved,

you will be asked if you would like to save the data. A data set can be copied and

saved under a different name by selecting File|Save as.

4.7

Maximum size of the data set and computation speed

In ECOM 2.0 new array handling technology has been introduced to enable the

analysis of very large data sets.

Theoretically, the size of the input data matrix is unlimited although, in practice, the

memory resources of the PC is usually the limiting factor. In tests we have run ECOM

with a data array of 5000 species x 5000 samples without difficulty.

Our new approach to data handling means that on a reasonably modern PC, most of

the computation, even on very large data sets, can be completed within a few

seconds.  All computations with data sets of up to 100 samples by 100 species are

usually almost instantaneous.

If you do run into speed problems with very large data sets, it will generally be

improved if there are no other Windows applications running at the time.

Copyright 2004  PISCES Conservation Ltd