project                package:proj4                R Documentation

_P_r_o_j_e_c_t_i_o_n _o_f _c_o_o_r_d_i_n_a_t_e_s

_D_e_s_c_r_i_p_t_i_o_n:

     Projection of lat/long coordinates or its inverse.

_U_s_a_g_e:

     project(xy, proj, inverse = FALSE, degrees = TRUE, silent = FALSE,
             ellps.default="sphere")

_A_r_g_u_m_e_n_t_s:

      xy: input (list, matrix or 2d-array) - see details below. 

    proj: projection definition 

 inverse: if 'TRUE' inverse projection is performed (from a
          cartographic projection into lat/long), otherwise projects
          from lat/long into a cartographic projection. 

 degrees: if 'TRUE' then the lat/long data is assumed to be in degrees,
          otherwise in radians 

  silent: if set to 'TRUE', warnings will be suppressed 

ellps.default: default ellipsoid that will be added if no datum or
          ellipsoid parameter is specified in 'proj'. Older versions of
          PROJ.4 didn't require a datum (and used sphere by default),
          but 4.5.0 and higher always require a datum or an ellipsoid.
          Set to 'NA' if no datum should be added to 'proj' (e.g. if
          you specify an ellipsoid directly).

_D_e_t_a_i_l_s:

     The input can be a list of two or more vectors (if the list
     contains more than two entries, only first two entries are used
     and a warning is issued), a two-dimensional matrix or array (the
     number of columns or rows must be exactly two) or a vector of the
     length 2. If the input is a list then the result will be a list
     with the entries named 'x' and 'y', otherwise the result is a
     matrix with two columns.

     When the list form is used, inputs are recycled with a warning
     when necessary.

     'proj' specifies the target (or source if inverse) projection. The
     format can be either a single (unnamed) string which contains all
     parameters: '"+proj=lcc +lat_1=33 +lat_2=45 +lat_0=39 +lon_0=-96"'
     or an unnamed vector of complete individual parameters:
     'c("+proj=lcc","+lat_1=33","+lat_2=45","+lat_0=39","+lon_0=-96")'
     or a named vector or list that will be composed into parameters:
     'list(proj="lcc", lat_1=33, lat_2=45, lat_0=39, lon_0=-96)'

     A list of some commonly used projections can be found at <URL:
     http://www.remotesensing.org/geotiff/proj_list/>

     if 'degrees' is 'TRUE' then the latitude and longitude are
     expected to be in degrees, if 'FALSE' then in radians.

_V_a_l_u_e:

     A two column matrix or list of coordinates. If the input was a
     list then the output will be a list, otherwise a matrix.

_R_e_f_e_r_e_n_c_e_s:

     <URL: http://www.remotesensing.org/proj/>

_E_x_a_m_p_l_e_s:

     ## this is just very simple, because we don't want to depend on
     ## maps package, so we can't show more useful stuff..
     data(state)
     s <- project(state.center, "+proj=merc")
     plot(s, type='n', asp=1)
     text(s,, state.abb)

