def to_proj4(self, as_dict=False):
string = "<STR_LIT:%s>" % self.proj.to_proj4()<EOL>string += "<STR_LIT>" % self.geogcs.to_proj4(toplevel=False)<EOL>string += "<STR_LIT:U+0020>" + "<STR_LIT:U+0020>".join(param.to_proj4() for param in self.params)<EOL>string += "<STR_LIT>" % self.unit.to_proj4()<EOL>string += "<STR_LIT>" + self.twin_ax[<NUM_LIT:0>].proj4 + self.twin_ax[<NUM_LIT:1>].proj4 + "<STR_LIT:u>" <EOL>string += "<STR_LIT>"<EOL>if as_dict:<EOL><INDENT>return dict([<EOL>entry.lstrip('<STR_LIT:+>').split('<STR_LIT:=>')<EOL>for entry in string.split()<EOL>if entry != "<STR_LIT>"<EOL>])<EOL><DEDENT>else:<EOL><INDENT>return string<EOL><DEDENT>
Returns the CS as a proj4 formatted string or dict.

Arguments:

- **as_dict** (optional): If True, returns the proj4 string as a dict (defaults to False).