[R-sig-Geo] Verify units of distance between coordinates

[Justin Michell]

Dear geo R group

I have a data frame like this:

df <- data.frame(Lon = c(29.6000,29.7333,30.3887,30.6667,30.6833,30.8667), Lat = c(-4.9000,-4.6000,-5.1280,-1.0667,-2.7500,-3.3833),  
                  LonWater = c(29.63333,29.63333,30.25000,30.65000,30.35444,30.83278), LatWater = c(-4.31667,-4.31667,-4.76667,-1.35000,-2.46667,-3.57000), DstClW = c(0.5842815,0.3004491,0.3870362,0.2837918,0.4340793,0.1897561) )

At these locations (Lon, Lat pairs) I calculated the shortest distance to a water source (DstClW) and where that source is (LonWater, LatWater).

I want to now determine what units DstClW is in, and also verify that these distances make sense and were calculated correctly. 

Any suggestions as to how this might be done?

Regards
Justin Michell