Purpose
This App can be used to perform detrended correspondence analysis (DCA). It is a multivariate method that corrects for the major problems (the arch effect and compression of the ends of the gradient) of Correspondence Analysis.
Installation
The app requires R software (recommended version 4.4.1) and package (vegan).
- Open the download page for R version 4.4.1
- Download the file named R-4.4.1-win.exe and install it
- Once you have successfully installed R, you can then install the App
- The App will download and install required R packages when you run it the first time.
Note that if you installed the App prior to instalilng R, the App icon will show in the Apps bar.
Simply click on that icon to continue after you have installed R.
Note: If downloading packages fails, a pop-up dialog will ask you to copy 2 lines of commands from Results Log and run them in R to complete downloading packages.
Related FAQ: FAQ-1214 What can I do when Origin has trouble launching R?
Operation
- Click App icon to open the dialog.
- Select data for sites and species.
- Customize DCA parameters:
- Downweight Rare Species: if selected, the influence of rare species is reduced.
- Number of Rescaling Iterations: Number of axis rescalings.
- Number of Segments in Rescaling: The number of segments the axis is divided into for re-scaling.
- Rescaling Threshold: The shortest Axes to be rescaled.
- Click OK to output report sheets.
Sample OPJU File
This app provides a sample OPJU file. Right click the App icon in the Apps Gallery window, and choose Show Samples Folder from the short-cut menu. A folder will open. Drag-and-drop the project file dca_sample.opju from the folder onto Origin. The Notes window in the project shows detailed steps.
Note: If you wish to save the OPJU after changing, it is recommended that you save to a different folder location (e.g. User Files Folder).