### Introduction

### Theory, R functions & Examples

en:ca_dca_r

Section: Ordination analysis

(library`cca`

`vegan`

) - if the environmental matrix is not specified,`cca`

function in`vegan`

package calculates unconstrained correspondence analysis^{1)}.(library`decorana`

`vegan`

) - this function implements the original DECORANA program, written by Mark Hill in Fortran, into R. For historical reasons^{2)}, only four DCA ordination axes are returned, and this is not easy to change.(P. Legendre,`CA`

*Numerical Ecology with R*, calledin the 2nd edition) - code can be found here.`CA.newr`

Alternatively to library

`vegan`

, there is also a package `ca`

with function `ca`

calculating correspondence analysis, with `plot`

, `plot3d`

and `summary`

functions. Package `ade4`

offers function `dudi.coa`

.The function

`decorana`

is implementing the original Hill's algorithm for DCA introduced by Fortran program DECORANA, which itself can calculate only four ordination axes; CANOCO behaves in the same way.en/ca_dca_r.txt · Last modified: 2021/03/03 11:52 by David Zelený