Mapping geom-cordinates to a map object in R - r

I am attempting to map some geom-points/cordinates to a map of the country Sri Lanka. I am able to map the district borders, and the population as expected, but I am having trouble plotting the geom points onto the map.
Install package
devtools::install_github("thiyangt/ceylon")
Load package
library("ceylon")
library(tidyverse)
library(sp)
library(viridis)
data(sf_sl_0)
Mapping only Sri Lanka
ggplot(sf_sl_0) + geom_sf()
Mapping the districts of Sri Lanka + population
ggplot(district) + geom_sf(aes(fill = population), show.legend = TRUE) + scale_fill_viridis()
Mappping specific geom-cordinates onto the map of Sri Lanka districts
These are the cordinates I want to map (yes, they are definitely within SL)
df_cord <- data.frame (lat = c("6.2441521", "6.2234515"),
lon = c("80.0590804", "80.2126109"))
I tried:
ggplot(district) +
geom_sf(df_cord) + scale_fill_viridis() +
geom_point(
data = df_cord,
aes(x = lon, y = lat),
size = 4,
shape = 23,
fill = "darkred"
)
But I get an error: Error in validate_mapping():
! mapping must be created by aes()
It looks like I might need to find the x,y cordinates of every geom point, and then map it with cord_sf? But I am not having an luck figuring out how to do this. I found a cool function called usmap::usmap_transform, which converts US geom points to x,y cordinates... but I can't figure out how to do the same for this map of Sri Lanka.
I am very new to mapping -- could someone please advise? Many thanks! I am open to other approaches/solutions!

One way would be to convert the coordinates to an sf object using st_as_sf and plot them using geom_sf. Don't forget to reproject the data to the same coordinate sistem:
library(ceylon)
library(tidyverse)
library(sp)
library(viridis)
library(sf)
data(district)
df_cord <- data.frame (lat = c(6.2441521, 6.2234515),
lon = c(80.0590804, 80.2126109))
df_cord <- df_cord %>%
st_as_sf(coords = c("lon", "lat"), crs = 4326) %>%
st_transform(crs = st_crs(district)) #reproject coords using the coordinate system of the polygons
#plot
ggplot(district) +
geom_sf(aes(fill = population), show.legend = TRUE) +
geom_sf(data = df_cord ,
size = 4,
shape = 23,
fill = "darkred") +
scale_fill_viridis()

I think you can't assign two data frames in ggplot.
Put the latitude and longitude values ​​inside the geom_point's aes(). Remember that longitude is the x-axis and latitude is the y-axis.
Try this:
ggplot() +
geom_sf(district) +
scale_fill_viridis() +
geom_point(
aes(x = c("80.0590804", "80.2126109"),
y =c("6.2441521", "6.2234515")),
size = 4,
shape = 23,
fill = "darkred"
)

You can add annotations (annotate) which will display your two coordinates. Also, set the right coordinate system like this:
ggplot(district) +
geom_sf(aes(fill = population), show.legend = TRUE) +
annotate("point", x = 80.0590804, y = 6.2441521, colour = "red", size = 2) +
annotate("point", x = 80.2126109, y = 6.2234515, colour = "red", size = 2) +
coord_sf(default_crs = sf::st_crs(4326)) +
scale_fill_viridis()
Output:

Related

Using geom_text() to display text in geom_polygon() [duplicate]

I am trying to label my polygons by using ggplot in R. I found a topic here on stackoverflow that I think is very close to what I want except with points.
Label points in geom_point
I found some methods online. Now I first need to find the central location of each shape and then I have to put these locations together with the name together. Then link this to the labeling function in geom_text()
ggplot centered names on a map
Since I have been trying for a long time now I decided to ask the question and hope that someone here can give me the final push to what I want. My plotting function:
region_of_interest.fort <- fortify(region_of_interest, region = "score")
region_of_interest.fort$id <- as.numeric(region_of_interest.fort$id)
region_of_interest.fort$id <- region_of_interest.fort$id
region_of_interest.fort1 <- fortify(region_of_interest, region = "GM_NAAM")
region_of_interest.fort1$id <- as.character(region_of_interest.fort1$id)
region_of_interest.fort1$id <- region_of_interest.fort1$id
idList <- unique(region_of_interest.fort1$id)
centroids.df <- as.data.frame(coordinates(region_of_interest))
names(centroids.df) <- c("Longitude", "Latitude")
randomMap.df <- data.frame(id = idList, shading = runif(length(idList)), centroids.df)
ggplot(data = region_of_interest.fort, aes(x = long, y = lat, fill = id, group = group)) +
geom_polygon() +
geom_text(centroids.df, aes(label = id, x = Longitude, y = Latitude)) +
scale_fill_gradient(high = "green", low = "red", guide = "colorbar") +
coord_equal() +
theme() +
ggtitle("Title")
It gives me the error: ggplot2 doesn't know how to deal with data of class uneval
My data
region_of_interest$GM_NAAM
[1] Groningen Haren Ooststellingwerf Assen Aa en Hunze Borger- Odoorn
[7] Noordenveld Westerveld Tynaarlo Midden-Drenthe
415 Levels: 's-Gravenhage 's-Hertogenbosch Aa en Hunze Aalburg Aalsmeer Aalten ... Zwolle
region_of_interest$score
[1] 10 -2 -1 2 -1 -4 -4 -5 0 0
Try something like this?
Get a data frame of the centroids of your polygons from the
original map object.
In the data frame you are plotting, ensure there are columns for
the ID you want to label, and the longitude and latitude of those
centroids.
Use geom_text in ggplot to add the labels.
Based on this example I read a world map, extracting the ISO3 IDs to use as my polygon labels, and make a data frame of countries' ID, population, and longitude and latitude of centroids. I then plot the population data on a world map and add labels at the centroids.
library(rgdal) # used to read world map data
library(rgeos) # to fortify without needing gpclib
library(maptools)
library(ggplot2)
library(scales) # for formatting ggplot scales with commas
# Data from http://thematicmapping.org/downloads/world_borders.php.
# Direct link: http://thematicmapping.org/downloads/TM_WORLD_BORDERS_SIMPL-0.3.zip
# Unpack and put the files in a dir 'data'
worldMap <- readOGR(dsn="data", layer="TM_WORLD_BORDERS_SIMPL-0.3")
# Change "data" to your path in the above!
worldMap.fort <- fortify(world.map, region = "ISO3")
# Fortifying a map makes the data frame ggplot uses to draw the map outlines.
# "region" or "id" identifies those polygons, and links them to your data.
# Look at head(worldMap#data) to see other choices for id.
# Your data frame needs a column with matching ids to set as the map_id aesthetic in ggplot.
idList <- worldMap#data$ISO3
# "coordinates" extracts centroids of the polygons, in the order listed at worldMap#data
centroids.df <- as.data.frame(coordinates(worldMap))
names(centroids.df) <- c("Longitude", "Latitude") #more sensible column names
# This shapefile contained population data, let's plot it.
popList <- worldMap#data$POP2005
pop.df <- data.frame(id = idList, population = popList, centroids.df)
ggplot(pop.df, aes(map_id = id)) + #"id" is col in your df, not in the map object
geom_map(aes(fill = population), colour= "grey", map = worldMap.fort) +
expand_limits(x = worldMap.fort$long, y = worldMap.fort$lat) +
scale_fill_gradient(high = "red", low = "white", guide = "colorbar", labels = comma) +
geom_text(aes(label = id, x = Longitude, y = Latitude)) + #add labels at centroids
coord_equal(xlim = c(-90,-30), ylim = c(-60, 20)) + #let's view South America
labs(x = "Longitude", y = "Latitude", title = "World Population") +
theme_bw()
Minor technical note: actually coordinates in the sp package doesn't quite find the centroid, but it should usually give a sensible location for a label. Use gCentroid in the rgeos package if you want to label at the true centroid in more complex situations like non-contiguous shapes.
The accepted answer here may work, but the actual question asked specifically notes that there is an error "ggplot2 doesn't know how to deal with data of class uneval."
The reason that it is giving you the error is because the inclusion of centroids.df needs to be a named variable (e.g. accompanied by "data=")
Currently:
ggplot(data = region_of_interest.fort, aes(x = long, y = lat, fill = id, group = group)) +
geom_polygon() +
geom_text(centroids.df, aes(label = id, x = Longitude, y = Latitude)) +
scale_fill_gradient(high = "green", low = "red", guide = "colorbar") +
coord_equal() +
theme() +
ggtitle("Title")
Should be (note: "data=centroids.df"):
ggplot(data = region_of_interest.fort, aes(x = long, y = lat, fill = id, group = group)) +
geom_polygon() +
geom_text(data=centroids.df, aes(label = id, x = Longitude, y = Latitude)) +
scale_fill_gradient(high = "green", low = "red", guide = "colorbar") +
coord_equal() +
theme() +
ggtitle("Title")
This issue was addressed here: How to deal with "data of class uneval" error from ggplot2?

R geom_point vs geom_line vs geom_path for US states shapefile

[US state with geom_path][1][US state with geom_point][2]I am using R to overlay US states shape file above ogallala region shape file. I would ideally like to have shape boundaries as line but I get poorly formed map when I try that (in pictures) but when I try geom_point it works alright. Can someone please explain what I am doing wrong. [US state with geom_line][3]
OG_HUC = read.csv("input/Ogallala_huc.csv")
OG_table =right_join(HUC8_map.df,OG_HUC,by = c("HUC_CODE"="HUC8"))
#OG_table = merge(HUC8_map.df,OG_HUC,by = "HUC8", sort = FALSE)
OG_table[is.na(OG_table)] = 0
#write.csv(OG_table,'OG_table.csv')
State <- readOGR(
dsn= paste0(getwd(),"/input/State") ,
layer="states"
)
State_map <- spTransform(State, CRS("+proj=longlat +datum=WGS84"))
State_map#data$id = rownames(State_map#data)
State_map.points = fortify(State_map, region="id")
centroids.df <- as.data.frame(coordinates(State_map))
names(centroids.df) <- c("Longitude", "Latitude") #more sensible column names
State_map.df1 = merge(State_map.points, State_map#data, by="id")
State_map.df2 = data.frame(id = State_map#data$id, State_map#data, centroids.df)
ggplot()+geom_polygon(data=OG_table,aes(x = long, y = lat, group=group),fill="lightskyblue",col="black", alpha = 0.3) +
geom_text(data = State_map.df2, aes(Longitude, Latitude, label=STATE_ABBR),col="black")+
#geom_path(data = OG_table, aes(long, lat, group=group),color="black") +
geom_point(data = State_map.df1, aes(long, lat, label=STATE_ABBR),color="black")+
coord_map(xlim = c(-108,-95),ylim = c(31,45))+
scale_fill_identity()
```enter image description here
[1]: https://i.stack.imgur.com/7XzeB.png
[2]: https://i.stack.imgur.com/9tAB8.png
[3]: https://i.stack.imgur.com/MtgXs.png
Try:
Library (maps)
Your_data %>% ggplot (aes(lat, lon)) +
Borders ("states") +
geom_polygon()

How to change legend shapes when using geom_sf?

I'm plotting points using geom_sf and ggplot, and would like to change the shape of the points. I can change them on the map, but the legend never reflects the shape of the points, even when using override.aes.
I can't tell if I'm missing something or if this is a bug. I've traced similar issues in the Tidyverse issue tracker, and this one is quite similar. But none of the "resolved" issues seem to address my problem.
Here is an example showing how ggplot fails to propagate the shape to the legend.
library(sf)
library(ggplot2)
cities <- tibble::tribble(
~ lon, ~ lat, ~ name, ~ pop,
5.121420, 52.09074, "Utrecht", 311367,
6.566502, 53.21938, "Groningen", 189991,
4.895168, 52.37022, "Amsterdam", 779808
) %>% sf::st_as_sf(coords = c("lon", "lat"), crs = 4326)
lines_sfc <- sf::st_sfc(list(
sf::st_linestring(rbind(cities$geometry[[1]], cities$geometry[[2]])),
sf::st_linestring(rbind(cities$geometry[[2]], cities$geometry[[3]]))
))
lines <- sf::st_sf(
id = 1:2,
size = c(10,50),
geometry = lines_sfc,
crs = 4326
)
ggplot(cities) +
geom_sf(aes(shape = name))
ggplot(cities) +
geom_sf(aes(shape = name)) +
scale_shape_manual(values = c(1:3),
guide = guide_legend(
override.aes = list(shape = c(1:3))))
I would expect the legend entries to have the same shapes as the map, but instead I get empty squares.
ggplot() +
geom_sf(data = cities, aes(shape = name), show.legend = "point") +
scale_shape_manual(values = c(1, 2, 3))

how to use gganimate package plot a dynamic map in R?

As I know gganimate has been in version 1.0.3,we can use transition_* function to plot a dynamic graph. But when I run following code ,there is an error :
Error in `$<-.data.frame`(`*tmp*`, "group", value = "") :
replacement has 1 row, data has 0
code:
library(ggmap)
library(gganimate)
world <- map_data("world")
world <- world[world$region!="Antarctica",]
data <- data.frame(state = c("Alabama","Alaska","Alberta","Alberta","Arizona"),
lon = c(-86.55,-149.52,-114.05,-113.25,-112.05),
lat = c(33.30,61.13,51.05,53.34,33.30)
)
ggplot()+
geom_map(data = world,
map = world,
aes(long,lat,map_id = region),
color = '#333300',
fill = '#663300') +
geom_point(data = data,
aes(x = lon, y = lat),
size = 2.5) +
geom_jitter(width = 0.1) +
transition_states(states = state)
You have no data defined in the top level ggplot() line, so state in transition_* comes out of nowhere.
It's also unclear to me why you have a geom_jitter level in your code. Like transition_*, it has no top level data / aesthetic mappings to inherit, so it would have thrown an error too, had transition_* not triggered an error first. In addition, even if we add the mappings, given the range of lat/lon coordinates in your data, jittering by 0.1 is hardly going to matter visually.
You can try the following:
# put data in top level ggplot()
ggplot(data,
aes(x = lon, y = lat))+
geom_map(data = world,
map = world,
aes(long,lat,map_id = region),
color = '#333300', fill = '#663300',
# lighter background for better visibility
alpha = 0.5) +
geom_point(size = 2.5) +
# limit coordinates to relevant range
coord_quickmap(x = c(-180, -50), y = c(25, 85)) +
transition_states(states = state)

Labeling center of map polygons in R ggplot

I am trying to label my polygons by using ggplot in R. I found a topic here on stackoverflow that I think is very close to what I want except with points.
Label points in geom_point
I found some methods online. Now I first need to find the central location of each shape and then I have to put these locations together with the name together. Then link this to the labeling function in geom_text()
ggplot centered names on a map
Since I have been trying for a long time now I decided to ask the question and hope that someone here can give me the final push to what I want. My plotting function:
region_of_interest.fort <- fortify(region_of_interest, region = "score")
region_of_interest.fort$id <- as.numeric(region_of_interest.fort$id)
region_of_interest.fort$id <- region_of_interest.fort$id
region_of_interest.fort1 <- fortify(region_of_interest, region = "GM_NAAM")
region_of_interest.fort1$id <- as.character(region_of_interest.fort1$id)
region_of_interest.fort1$id <- region_of_interest.fort1$id
idList <- unique(region_of_interest.fort1$id)
centroids.df <- as.data.frame(coordinates(region_of_interest))
names(centroids.df) <- c("Longitude", "Latitude")
randomMap.df <- data.frame(id = idList, shading = runif(length(idList)), centroids.df)
ggplot(data = region_of_interest.fort, aes(x = long, y = lat, fill = id, group = group)) +
geom_polygon() +
geom_text(centroids.df, aes(label = id, x = Longitude, y = Latitude)) +
scale_fill_gradient(high = "green", low = "red", guide = "colorbar") +
coord_equal() +
theme() +
ggtitle("Title")
It gives me the error: ggplot2 doesn't know how to deal with data of class uneval
My data
region_of_interest$GM_NAAM
[1] Groningen Haren Ooststellingwerf Assen Aa en Hunze Borger- Odoorn
[7] Noordenveld Westerveld Tynaarlo Midden-Drenthe
415 Levels: 's-Gravenhage 's-Hertogenbosch Aa en Hunze Aalburg Aalsmeer Aalten ... Zwolle
region_of_interest$score
[1] 10 -2 -1 2 -1 -4 -4 -5 0 0
Try something like this?
Get a data frame of the centroids of your polygons from the
original map object.
In the data frame you are plotting, ensure there are columns for
the ID you want to label, and the longitude and latitude of those
centroids.
Use geom_text in ggplot to add the labels.
Based on this example I read a world map, extracting the ISO3 IDs to use as my polygon labels, and make a data frame of countries' ID, population, and longitude and latitude of centroids. I then plot the population data on a world map and add labels at the centroids.
library(rgdal) # used to read world map data
library(rgeos) # to fortify without needing gpclib
library(maptools)
library(ggplot2)
library(scales) # for formatting ggplot scales with commas
# Data from http://thematicmapping.org/downloads/world_borders.php.
# Direct link: http://thematicmapping.org/downloads/TM_WORLD_BORDERS_SIMPL-0.3.zip
# Unpack and put the files in a dir 'data'
worldMap <- readOGR(dsn="data", layer="TM_WORLD_BORDERS_SIMPL-0.3")
# Change "data" to your path in the above!
worldMap.fort <- fortify(world.map, region = "ISO3")
# Fortifying a map makes the data frame ggplot uses to draw the map outlines.
# "region" or "id" identifies those polygons, and links them to your data.
# Look at head(worldMap#data) to see other choices for id.
# Your data frame needs a column with matching ids to set as the map_id aesthetic in ggplot.
idList <- worldMap#data$ISO3
# "coordinates" extracts centroids of the polygons, in the order listed at worldMap#data
centroids.df <- as.data.frame(coordinates(worldMap))
names(centroids.df) <- c("Longitude", "Latitude") #more sensible column names
# This shapefile contained population data, let's plot it.
popList <- worldMap#data$POP2005
pop.df <- data.frame(id = idList, population = popList, centroids.df)
ggplot(pop.df, aes(map_id = id)) + #"id" is col in your df, not in the map object
geom_map(aes(fill = population), colour= "grey", map = worldMap.fort) +
expand_limits(x = worldMap.fort$long, y = worldMap.fort$lat) +
scale_fill_gradient(high = "red", low = "white", guide = "colorbar", labels = comma) +
geom_text(aes(label = id, x = Longitude, y = Latitude)) + #add labels at centroids
coord_equal(xlim = c(-90,-30), ylim = c(-60, 20)) + #let's view South America
labs(x = "Longitude", y = "Latitude", title = "World Population") +
theme_bw()
Minor technical note: actually coordinates in the sp package doesn't quite find the centroid, but it should usually give a sensible location for a label. Use gCentroid in the rgeos package if you want to label at the true centroid in more complex situations like non-contiguous shapes.
The accepted answer here may work, but the actual question asked specifically notes that there is an error "ggplot2 doesn't know how to deal with data of class uneval."
The reason that it is giving you the error is because the inclusion of centroids.df needs to be a named variable (e.g. accompanied by "data=")
Currently:
ggplot(data = region_of_interest.fort, aes(x = long, y = lat, fill = id, group = group)) +
geom_polygon() +
geom_text(centroids.df, aes(label = id, x = Longitude, y = Latitude)) +
scale_fill_gradient(high = "green", low = "red", guide = "colorbar") +
coord_equal() +
theme() +
ggtitle("Title")
Should be (note: "data=centroids.df"):
ggplot(data = region_of_interest.fort, aes(x = long, y = lat, fill = id, group = group)) +
geom_polygon() +
geom_text(data=centroids.df, aes(label = id, x = Longitude, y = Latitude)) +
scale_fill_gradient(high = "green", low = "red", guide = "colorbar") +
coord_equal() +
theme() +
ggtitle("Title")
This issue was addressed here: How to deal with "data of class uneval" error from ggplot2?

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