project {rgdal} | R Documentation

## Projection of coordinate matrices

### Description

Interface to the PROJ.4 library of projection functions for geographical position data, no datum transformation possible. Use `transform()` for extended support.

### Usage

    project(xy, proj, inv = FALSE)

### Arguments

`xy` | 2-column matrix of coordinates
`proj` | character string of projection arguments; the arguments must be entered exactly as in the PROJ.4 documentation, in particular there cannot be any white space in +<arg>=<value> strings, and successive such strings can only be separated by blanks.
`inv` | default FALSE, if TRUE inverse projection to geographical coordinates

### Details

Full details of projection arguments available from website below, and examples in file "epsg" in the data directory installed with PROJ.4.

### Value

A two column matrix with projected coordinates.

### Note

The locations of Hawaii and Alaska in the data source are (putting it mildly) arbitrary, please avoid airlines using these positions.

### Author(s)

Barry Rowlingson, Roger Bivand Roger.Bivand@nhh.no

### References

http://www.remotesensing.org/proj/

### See Also

`CRS-class`, `spTransform-methods`

### Examples

    data(state)
    res <- project(cbind(state.center$x, state.center$y), "+proj=lcc +lat_1=48 +lat_2=33 +lon_0=-100")
    res1 <- project(res, "+proj=lcc +lat_1=48 +lat_2=33 +lon_0=-100", inv=TRUE)
    summary(res1 - cbind(state.center$x, state.center$y))
    plot(cbind(state.center$x, state.center$y), asp=1, type="n")
    text(cbind(state.center$x, state.center$y), state.abb)
    plot(res, asp=1, type="n")
    text(res, state.abb)

[Package rgdal version 0.4-4 Index]