It is important to cross-check coordinates by visual and other means. One
approach is to compare the country (and lower level administrative subdivisions)
of the site as specified by the records, with the country implied by the
coordinates (Hijmans et al., 1999). In the example below we use the coordinates
function from the sp package to create a SpatialPointsDataFrame, and
then the over function, also from sp, to do a point-in-polygon query with the
countries polygons