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.
The app requires R software (minimum required version 3.4.1) and package (vegan). If R is not yet installed on your computer, please follow these steps.
- Run Origin as administrator. Download the file dca.opx and install it by choosing Tools->Package Manager->Tools->Install a Package.
- After App installation, a pop-up dialog will ask if you agree to download and install R software before it proceeds. (If automatic downloading fails, you can install the App again or download R from here.)
- For the first time you launch the App, it downloads dependent R packages. Wait a few minutes until it is completed.
Note: If packages download 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.
If you reinstall or upgrade R after installing the app, it would not work properly. Please reinstall the app.
- 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).