I have a $5 Starbucks gift card that I simply can't remember to use; I've had it since Christmas. So, I will mail it (within the U.S.A.) to the first commenter who can identify the longitude/latitude (within 5km) where two of these three vacation photos were taken (photos below). *****Update 3/30/2013: locations A and C have been identified*****. Each location must be identified by longitude/latitude; names don't count. Here are some short instructions for obtaining longitude/latitude values from Google Maps: 1 2. I know this is a stretch for R-bloggers, but I will be checking longitude/latitude entries using the following `R` code:

# convert degree, minute, second to decimal dms2dec <- function(deg, min, sec) deg + (min + sec/60)/60 # convert degrees to radians d2r <- function(d) d * pi / 180 # compute great circle distance (km) between two coordinates # given in radians using the Haversine formula hgcd <- function(lon1, lat1, lon2, lat2) { erth <- 6371 # average radius of earth (km) dlon <- (lon2 - lon1) dlat <- (lat2 - lat1) a <- sin(dlat/2)^2 + cos(lat1) * cos(lat2) * sin(dlon/2)^2 c <- 2 * asin(min(1,sqrt(a))) erth * c }

Fun!

The first one is Nasau, Bahamas: 25.091818,-77.323151

The third one is Miami: 25.734344,-80.131531

Hope you enjoyed the cruise!

Winner!

The actual coordinates (as reported by my GPS) were:

Miami: 25.77781, -80.17162

Nassau: 25.08292, -77.33925

The R function above (

hgcd) indicates that your answer was off by 6.3km in Miami and 1.9km in Nassau. That averages less than 5km. Email me (biostatmatt@gmail.com) with a mailing address, and I'll mail the Starbucks gift card.Actually, that third picture was shot on Miami Beach, facing Miami, probably on Collins Avenue