How does geom_point delete rows containing missing values?

Question

I am not sure why none of my data is displayed on the map.

Store_ID visits CRIND_CC ISCC EBITDAR top_bottom Latitude Longitude (int) (int) (int) (int) (dbl) (chr) (fctr) (fctr) 1 92 348 14819 39013 76449.15 top 41.731373 -93.58184 2 2035 289 15584 35961 72454.42 top 41.589428 -93.80785 3 50 266 14117 27262 49775.02 top 41.559017 -93.77287 4 156 266 7797 25095 28645.95 top 41.6143 -93.834404 5 66 234 8314 18718 46325.12 top 41.6002 -93.779236 6 207 18 2159 17999 20097.99 bottom 41.636208 -93.531876 7 59 23 10547 28806 52168.07 bottom 41.56153 -93.88083 8 101 23 1469 11611 7325.45 bottom 41.20982 -93.84298 9 130 26 2670 13561 14348.98 bottom 41.614517 -93.65789 10 130 26 2670 13561 14348.98 bottom 41.6145172 -93.65789 11 24 27 17916 41721 69991.10 bottom 41.597134 -93.49263 > dput(droplevels(top_bottom)) structure(list(Store_ID = c(92L, 2035L, 50L, 156L, 66L, 207L, 59L, 101L, 130L, 130L, 24L), visits = c(348L, 289L, 266L, 266L, 234L, 18L, 23L, 23L, 26L, 26L, 27L), CRIND_CC = c(14819L, 15584L, 14117L, 7797L, 8314L, 2159L, 10547L, 1469L, 2670L, 2670L, 17916L ), ISCC = c(39013L, 35961L, 27262L, 25095L, 18718L, 17999L, 28806L, 11611L, 13561L, 13561L, 41721L), EBITDAR = c(76449.15, 72454.42, 49775.02, 28645.95, 46325.12, 20097.99, 52168.07, 7325.45, 14348.98, 14348.98, 69991.1), top_bottom = c("top", "top", "top", "top", "top", "bottom", "bottom", "bottom", "bottom", "bottom", "bottom" ), Latitude = structure(c(11L, 4L, 2L, 7L, 6L, 10L, 3L, 1L, 8L, 9L, 5L), .Label = c("41.20982", "41.559017", "41.56153", "41.589428", "41.597134", "41.6002", "41.6143", "41.614517", "41.6145172", "41.636208", "41.731373"), class = "factor"), Longitude = structure(c(3L, 7L, 5L, 8L, 6L, 2L, 10L, 9L, 4L, 4L, 1L), .Label = c("-93.49263", "-93.531876", "-93.58184", "-93.65789", "-93.77287", "-93.779236", "-93.80785", "-93.834404", "-93.84298", "-93.88083"), class = "factor")), row.names = c(NA, -11L), .Names = c("Store_ID", "visits", "CRIND_CC", "ISCC", "EBITDAR", "top_bottom", "Latitude", "Longitude"), class = c("tbl_df", "tbl", "data.frame")) 

Creation of the plot:

 map <- qmap('Des Moines') + geom_point(data = top_bottom, aes(x = as.numeric(Longitude), y = as.numeric(Latitude)), colour = top_bottom, size = 3) 

I get a warning message:

 Removed 11 rows containing missing values (geom_point). 

However, this works without using ggmap() :

 ggplot(top_bottom) + geom_point(aes(x = as.numeric(Longitude), y = as.numeric(Latitude)), colour = top_bottom, size = 3) 

How to get overlay points on ggmap?

Answer 1

You are using as.numeric() with factor . As you can see here , which gives you the level number for the factor (not the number). Unsurprisingly, all these levels are points not on the canvas displayed for "Des Moines".

Use as.numeric(as.character(Latitude)) and as.numeric(as.character(Longitude)) as ugly as it seems.

Answer 2

Seeing an example of data, it seems that there is one data point that does not remain in the map area.

 library(dplyr) library(ggplot2) library(ggmap) ### You can find lon/lat for bbox using your ggmap object. ### For instance, des1 <- ggmap(mymap1) ### str(des1) ### You could use bb2bbox() in the ggmap package to find lon/lat. filter(top_bottom, between(Latitude, 41.27057, 41.92782), between(Longitude, -94.04787, -93.16897)) -> inside setdiff(top_bottom, inside) # Store_ID visits CRIND_CC ISCC EBITDAR top_bottom Latitude Longitude #1 101 23 1469 11611 7325.45 bottom 41.20982 -93.84298 

Since you used qmap() without specifying a scale, I don't know what level of scaling you had. Play a little. In the first case, one data point is missing; Removed 1 rows containing missing values (geom_point).

 mymap1 <- get_map('Des Moines', zoom = 10) ggmap(mymap1) + geom_point(data = top_bottom, aes(x = as.numeric(Longitude), y = as.numeric(Latitude)), colour = top_bottom, size = 3) 

 mymap2 <- get_map('Des Moines', zoom = 9) ggmap(mymap2) + geom_point(data = top_bottom, aes(x = as.numeric(Longitude), y = as.numeric(Latitude)), colour = top_bottom, size = 3) 

So, the main thing, I think, is that you want to make sure that you choose the right zoom level for your dataset. To do this, you can specify the increase in qmap() . Hope this helps you.

DATA

 top_bottom <- structure(list(Store_ID = c(92L, 2035L, 50L, 156L, 66L, 207L, 59L, 101L, 130L, 130L, 24L), visits = c(348L, 289L, 266L, 266L, 234L, 18L, 23L, 23L, 26L, 26L, 27L), CRIND_CC = c(14819L, 15584L, 14117L, 7797L, 8314L, 2159L, 10547L, 1469L, 2670L, 2670L, 17916L ), ISCC = c(39013L, 35961L, 27262L, 25095L, 18718L, 17999L, 28806L, 11611L, 13561L, 13561L, 41721L), EBITDAR = c(76449.15, 72454.42, 49775.02, 28645.95, 46325.12, 20097.99, 52168.07, 7325.45, 14348.98, 14348.98, 69991.1), top_bottom = structure(c(2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = c("bottom", "top"), class = "factor"), Latitude = c(41.731373, 41.589428, 41.559017, 41.6143, 41.6002, 41.636208, 41.56153, 41.20982, 41.614517, 41.6145172, 41.597134 ), Longitude = c(-93.58184, -93.80785, -93.77287, -93.834404, -93.779236, -93.531876, -93.88083, -93.84298, -93.65789, -93.65789, -93.49263)), .Names = c("Store_ID", "visits", "CRIND_CC", "ISCC", "EBITDAR", "top_bottom", "Latitude", "Longitude" ), class = "data.frame", row.names = c("1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11"))