Adding a legend / text table in ggmap with multiple layers

Question

I draw a route and impose on ggmap, and I need to add a legend to list the names that represent the points i.e.

1 Bill Harris, 2 Ann Jones, etc ..

I prepared sample data.

structure(list(business.names = structure(c(8L, 9L, 5L, 6L, 7L, 1L, 4L, 3L, 2L, 10L), .Label = c("Bill Harris", "Anne Jones", "Sue Perkins", "Morris Jones", "Bert Harris", "Bob Jones", "Mike Taylor", "Paul Jones", "John Roberts", "Fred Morris"), class = "factor"), X1 = structure(c(7L, 8L, 10L, 9L, 3L, 2L, 1L, 4L, 5L, 6L), .Label = c("53.186744", "53.1884117", "53.1894004", "53.189836", "53.1902965", "53.1905138631287", "53.1912196", "53.1916771", "53.193418", "53.1934748"), class = "factor"), X2 = structure(c(7L, 3L, 2L, 1L, 5L, 4L, 6L, 10L, 9L, 8L), .Label = c("-2.881248", "-2.8814698", "-2.8846099", "-2.88802", "-2.8886692", "-2.890165", "-2.8902453", "-2.89043889005541", "-2.8919373", "-2.893896" ), class = "factor")), .Names = c("business.names", "X1", "X2"), row.names = c(10L, 9L, 8L, 1L, 7L, 6L, 3L, 4L, 5L, 2L), class = "data.frame") 

Here is my code for today. Note that for geom_path and geom.route, the Size and color parameter is outside the AES function. I do not need to adjust the size or color based on the data. If I put the size and color in the AES function, I will get a legend, but that is not what I want. It uses data points, not the name of the company.

I'm not even sure that Legend is the best way to go. I just need the data displayed on the chart in a simple table.

 create.map<-function(lst){ require("ggmap") require("qmap") way.points<-data.frame(lapply(lst[,1:3], as.character), stringsAsFactors=FALSE) rte.from <- apply(way.points[-nrow(way.points),2:3],1,paste,collapse=",") rte.to <- apply(way.points[-1,2:3],1,paste,collapse=",") rte <- do.call(rbind, mapply(route, rte.from, rte.to, SIMPLIFY=FALSE, MoreArgs=list(mode="walking",structure="legs"))) map.centre<-c(mean(as.numeric(way.points$X2)),mean(as.numeric(way.points$X1))) coords <- rbind(as.matrix(rte[,7:8]),as.matrix(rte[nrow(rte),9:10])) coords <- as.data.frame(coords) ggm <- qmap(location=map.centre,zoom = 15, maptype = "road", legend="topright") ggm + geom_path(data=coords,aes(x=startLon,y=startLat),color="blue",size=2)+ geom_point(data=way.points,aes(x=as.numeric(X2),y=as.numeric(X1)), size=10,color="yellow")+ geom_text(data=way.points, aes(x=as.numeric(X2),y=as.numeric(X1), label=seq_along(X1))) } 

Answer 1

Here is one opportunity. You might want to streamline company names and use geom_point again to create a legend. In this geom_point you use alpha = 0 . Therefore, you do not see any dots; you just see the yellow dots as indicated in the first geom_point . Here your data is called mydf .

 foo <- mutate(mydf, business.names = paste(seq_along(X1), business.names, sep = " ")) # business.names X1 X2 #1 1 Paul Jones 53.1912196 -2.8902453 #2 2 John Roberts 53.1916771 -2.8846099 #3 3 Bert Harris 53.1934748 -2.8814698 #4 4 Bob Jones 53.193418 -2.881248 #5 5 Mike Taylor 53.1894004 -2.8886692 #6 6 Bill Harris 53.1884117 -2.88802 #7 7 Morris Jones 53.186744 -2.890165 #8 8 Sue Perkins 53.189836 -2.893896 #9 9 Anne Jones 53.1902965 -2.8919373 #10 10 Fred Morris 53.1905138631287 -2.89043889005541 create.map<-function(lst){ require("ggmap") require("qmap") way.points <-data.frame(lapply(lst[,1:3], as.character), stringsAsFactors=FALSE) rte.from <- apply(way.points[-nrow(way.points),2:3],1,paste,collapse=",") rte.to <- apply(way.points[-1,2:3],1,paste,collapse=",") rte <- do.call(rbind, mapply(route, rte.from, rte.to, SIMPLIFY=FALSE, MoreArgs=list(mode="walking",structure="legs"))) map.centre<-c(mean(as.numeric(way.points$X2)),mean(as.numeric(way.points$X1))) coords <- rbind(as.matrix(rte[,7:8]),as.matrix(rte[nrow(rte),9:10])) coords <- as.data.frame(coords) ggm <- qmap(location=map.centre,zoom = 15, maptype = "road", legend="topright") ggm + geom_path(data=coords,aes(x=startLon,y=startLat),color="blue",size=2)+ geom_point(data=way.points,aes(x=as.numeric(X2),y=as.numeric(X1)), size=10,color="yellow")+ geom_point(data=way.points,aes(x=as.numeric(X2),y=as.numeric(X1), color = factor(business.names, levels=business.names)), alpha = 0) + geom_text(data=way.points, aes(x=as.numeric(X2),y=as.numeric(X1), label=seq_along(X1))) + scale_color_discrete(name = "Business names") + theme(legend.key = element_rect(fill = NA)) } create.map(foo)