r - Chart 3 variables in ggplot -

i struggling combine colour coding z variable (shipspeedgps.knots.) in y variable (lon) , x var (lat) plot.

i have mapped route via following commands

nwsmap = qmap('brunei', zoom=3)  nwsmap + geom_point(aes(x=lon, y=lat), data=d3) 

and separately have been able colour code route without base map following commands

d3plot = ggplot(data = d3, aes(x=lat, y=lon, colour=yval))  d3plot + geom_point(aes(colour = d3$shipspeedgps.knots.)) 

ideally combine both of these features 1 chart. 'brunei' map base route colour coded based on speed of vessel. can visually show captains of vessels going unnecessarily fast , wasting fuel.

str(d3) 'data.frame':   74843 obs. of  15 variables:  $ date                   : date, format: "2015-04-27"  $ time                   : factor w/ 86401 levels "","0:00:00" $ lat                    : num  -19.9 $ lon                    : num  117 $ shipcourse.deg.        : int  182 $ shipspeedgps.knots.    : num  13.4  $ shipspeedlog.knots.    : num  13.6 $ shipspeedpropllr.knots.: num  14.3 $ wind.dir..rel...deg.   : int  0 $ wind.speed.abs...knots.: num  13.3 $ windspeedrel...knots.  : num  0  $ shaftpower.kw.         : int  7526  $ shaftspeed.rpm.        : num  58.8 $ shafttorque.knm.       : int  1222 $ shaftthrust..kn.       : int  915 

figured solution

nwsmap2 = get_map(location = "brunei", zoom = 3)  ggmap(nwsmap2) + geom_point(data = d3, aes(x = lon, y = lat, color = shipspeedgps.knots.)) + scale_colour_gradient(low="green", high="red", limits=c(10,16))