[R] code to convert 3D geographical coordinates to Cartesian?

[Tom Roche]

https://stat.ethz.ch/pipermail/r-help/2012-December/332658.html
>> Is there packaged code to convert geographical coordinates (e.g.,
>> longitude, latitude, elevation) to Cartesian coordinates in 3-space?
...
>> Net: the task seems straightforward enough, but there's certainly
>> scope for error, so I'd prefer to use tested, well-used code if
>> available.

https://stat.ethz.ch/pipermail/r-help/2012-December/332666.html
> Have you checked the spatial stats task view on CRAN?

> http://cran.r-project.org/web/views/Spatial.html

I have, and can't believe that functionality this fundamental is not
API. But I have looked at several packages and am not seeing it. I
suspect that either it's so low-level that it's just not exposed as API,
or just that there is API but I'm not seeing it in the package docs
("hidden in plain sight"). Hence I ask

>> Am I missing something?

TIA, Tom Roche <Tom_Roche at pobox.com>