I am trying to create an interactive map of football stadiums in the UK with the leaflet package in R. I understand that I can use a custom image as the icon on the map. For a given stadium, I would like to use the badge of the club that plays there as the icon. Initially I am trying to solve the simpler problem of just using one custom image for all the stadiums with the hope that once I can solve this, I will be able to generalise and have one custom image per stadium. I will provide a simplified data set of just two stadiums for the purposes of this question.
So far I have tried using this picture (https://upload.wikimedia.org/wikipedia/en/e/e5/AFC_Bournemouth_%282013%29.svg) of the Bournemouth badge however it does not appear on the map when run. I think R cannot properly access this image but I am not sure what types it can access or how it accesses them.
So far my code looks like this
library(leaflet)
# Create Data
finalData <- data.frame(Club = c("A.F.C. Bournemouth", "A.F.C. Wimbledon"), Latitude = c("50.7352","51.4051"), Longitude = c("-1.83839","-0.281984"), stringsAsFactors = FALSE)
# Create map using leaflet
m <- leaflet() %>%
addTiles()
# Attempt to create custom icon using the linked picture
BournemouthIcon = makeIcon("https://upload.wikimedia.org/wikipedia/en/e/e5/AFC_Bournemouth_%282013%29.svg", iconWidth = 8, iconHeight = 8)
m %>% addMarkers(lat = as.numeric(finalData$Latitude),
lng = as.numeric(finalData$Longitude),
clusterOptions = markerClusterOptions(),
icon = BournemouthIcon)
I expect to see the 2 stadiums plotted on the map with the Bournemouth badge as the marker but instead the markers are blank.1 It appears R knows where to plot the points (since if you zoom out it detects the cluster of points), however it does not know what to mark the point with.2 This links back to my misunderstanding of how R is reading the picture I supplied. Any help with how to properly build a custom marker and then pass it to addMarkers would be greatly appreciated. Furthermore some guidance on generalising this to having a unique custom picture for each marker would also be great!
Related
I am trying to create an interactive map (using the simplevis and leaflet packages) to be used in an RMarkdown HTML presentation. The popups work fine when no polygon is added but as soon as the polygon is added the popups can no longer be accessed.
The purpose is to have popups for the sf point data and to only show the legend of the point data. The polygon is added to show the boundries.
How can I fix this?
Sample data and code
library(sf)
library(leaflet)
library(simplevis)
leaf_sf_col(example_point,
col_var = trend_category,
popup = TRUE) %>%
leaflet::addPolygons(data = sf::st_transform(example_borders, 4326),
color = "#35B779",
weight = 3,
fillOpacity = 0,
opacity = 1)
Use addPolylines instead of addPolygons, then the polygon feature won't be capturing the click events (which is what I think is happening) because its only lines instead of an area-covering polygon.
I am trying to overlay a heatmap of polygons on my map and then be able to zoom into different parts of it depending on user input.
The code works fine when I remove the heatmap. The user is able to jump around from place to place (based on a dropdown list).
With the polygons it works the first time fully,
the second dropdown choice causes just a map to show with no polygons and the location does not shift,
and the third dropdown choice nothing shows.
output$HMmapstation <- renderLeaflet({
x <- NA
x <- input$HMstation #picking the place to view
x <- leaflet_map %>% setView(preloaded_stations[which(preloaded_stations$name == x),]$longitude,
preloaded_stations[which(preloaded_stations$name == x),]$latitude,
zoom = 14) %>% clearShapes()
x <- x %>% addPolygons(data=polys_dat, color = ~pal(polys_dat#plotOrder),
smoothFactor=.1, stroke = FALSE, fillOpacity = 0.1)
x
})
The leaflet map is created globally above the server and is as follows:
leaflet_map <- (leaflet() %>%
addProviderTiles("OpenStreetMap.BlackAndWhite",
options = providerTileOptions(noWrap = TRUE,minZoom=9)) %>%#~pal(seq(1,537,1))~rainbow(50, start=0,end=.3, alpha = NULL)
setMaxBounds(-0.715485, 51.252031, 0.514984, 51.745313))
I just cant seem to figure out why it would work once and then stop. Especially since without the polygon it works as expected.
Thank you in advance for any direction you can give me.
Leaflet is an amazing addition to R's quiver, I am starting to use it quite a bit at work and at times I also struggle with lost functionality as layers build. I do not have an answer for you working directly in R, but I have a suggestion.
One of the things that I am discovering as I become a Javascript D3 developer is that the last object into a JS visualization is on top.
So this means as you stack polygons, lines, and other objects and data onto a map, it is possible to BLOCK the visibility/functionality of objects below it.
If you are familiar with Javascript, you could open the devtools in chrome and look to see how the layers are being applied to the map.
As you do this, try to think about how R will call out to JS to compile the web graphic it makes and then see if you can re-order something in your R stack, or turn a shape into an outline so that the shape below retains function.
And it is possible after the graphic is "extruded' from R to go in and manually tweak the javascript controlling the features you are using with a lot more control than you have in R itself. I have done some editing on the resulting file set successfully.
There is a LOT more help in working on leaflet in JS directly here and around the web. You may be able to find a quicker answer that way.
The fix ended up being to put the leaflet in a reactive rather than a renderLeaflet.
I also re-ordered based on bethanyP's response so thank you!
Background: I am currently drawing a leaflet map using the following code:
library(leaflet)
leaflet()%>%
addProviderTiles("Stamen.TerrainBackground")%>%
setView(lng=-81,lat=45,zoom=6)
Problem: The problem is that it takes around 4 seconds to have the map appear. This is an undesirable feature when I integrate the map with Rshiny, given that the website appears blank until the map finally loads.
I'm wondering two things:
1) Is there an open source map that is known to load quickly compared to other maps.
2) If 1) is not possible, I have noticed that in google maps, the tiles of the map start appearing in sequence. At least like that the user is able to know that the map is loading. Is there a way of having the tiles be drawn sequentially like that?
If you mean the tiles are slow to load, that is most likely either a problem with the tile provider or a problem with your connection. Leaflet itself is usually very fast in my experience.
As far as the tile provider, I've always had good success with open street map in JS.
With R it looks like this link https://rstudio.github.io/leaflet/ has the following example using OSM:
library(leaflet)
m <- leaflet() %>%
addTiles() %>% # Add default OpenStreetMap map tiles
addMarkers(lng=174.768, lat=-36.852, popup="The birthplace of R")
m # Print the map
So calling "addTiles() %>% should use open street map as default.
I'm using R, and I want to overlay some raster data (e.g. a temperature map from a model) over an interactive map which allows panning and zooming. Ideally, I'd like to overlay over Google Maps or OpenStreetMaps. The input data can be in shapefiles, KML, raster data or whatever comes in handy.
I know I can easily do this non-interactively using either googleVis, ggmap or RgoogleMaps. But I do not want to use tiles, I want interaction! Zooming, panning etc., directly from the browser.
googleVis, as far as I know, unfortunately only allows to show interactively points or addresses, not areas.
This question is very similar but I definitely want to try to do this using R. I can create the KML or geoJSON from R, but how do I overlay it from R directly?
OpenStreetMaps is also fine, however I've not found any reference on how to overlay data over it from R, despite the fact that OSM seems to have a pretty straightforward API.
The mapview package has been developed for this particular purpose. It also comes with a variety of background map layers. For a short introduction to what mapview is capable of, feel free to browse the package vignette. Here, for example, is some code that displays locations of selected breweries in Franconian Switzerland overlaid by a sample Landsat 8 scene (band 10). Check out ?breweries91 and ?poppendorf to retrieve information about the data used below and ?mapview to grow familiar with the numerous costumization options.
## require package
# install.packages("mapview")
library(mapview)
## visualize breweries and add landsat 8 band 10
mapview(breweries91) +
poppendorf[[10]]
The leaflet package may be of interest for you. You can easily add a raster object. From the documentation
Two-dimensional RasterLayer objects (from the raster package) can be
turned into images and added to Leaflet maps using the addRasterImage
function.
And here is an example also from the documentation:
library(leaflet)
library(raster)
r <- raster("nc/oisst-sst.nc")
pal <- colorNumeric(c("#0C2C84", "#41B6C4", "#FFFFCC"), values(r),
na.color = "transparent")
leaflet() %>% addTiles() %>%
addRasterImage(r, colors = pal, opacity = 0.8) %>%
addLegend(pal = pal, values = values(r),
title = "Surface temp")
Sorry in advance for the wall of text. I am creating a sort of novel type of choropleth map, in which countries are shaded based on different categorical variables. The way I've set up the app, I assign each country an RGB value based on its levels of each of the underlying variables and I want the map to show that RGB value--seems simple, right?
Unfortunately, most of the map visualizations seem to want to do the color selection for me, rather than letting me choose. The best I've been able to do is to treat the data as categorical and I end up with the same number of categories as countries. This worked fairly well for rworldmap. The problem is, I'm developing this for web use, and I'd really like to have tooltips so that you can hover over a particular country and this doesn't work with rworldmap, as it's just a basic plot. Also, the rworldmap output is not particularly nice looking.
Here's the code I used with that:
mapjoin <- joinCountryData2Map(db, joinCode="ISO3",
nameJoinColumn="iso", mapResolution="high")
mapCountryData(mapjoin, nameColumnToPlot="iso", addLegend=FALSE,
catMethod="categorical", colourPalette=db$rgb, mapTitle=input$year)
I have experimented with googleVis, but I was having a lot of trouble with that--the map would just disappear for no reason and I'd have to reload the page, which I believe was an issue with the Shiny bindings in the googleVis package. I ultimately went with googleCharts (https://github.com/jcheng5/googleCharts), which clears up the problems with the bindings.
However, I'm still having problems.
Here's the reactive function:
output$mapviz <- reactive({
db <- genRgb()
list(
data=googleDataTable(db[c("country", "id")]),
options=list(legend="none", projection="kavrayskiy-vii", colors=db$rgb)
)
)}
and here's the output call:
googleGeoChart("mapviz", width="100%", height="780px")
As you can see, there's not a specific way to clue the JS app that it's categorical data, so as a result, it's making a choropleth with 182 different gradient stop points. Usually this works fine, but occasionally something weird happens and a country mysteriously ends up in an intermediate place between colors. I can always tell that there's a problem because certain countries are supposed to be specific colors (for instance, the U.S. will show as #0000FF, and it's pretty obvious when it's not). I've found that I can go to a different chart type (the app uses other googleCharts types) and then return to the map and usually it's fixed. So it's completely inconsistent.
So with that in mind, can anyone suggest a better mapping tool that I can implement in Shiny that would work well for this purpose?
Thanks!
Check out leaflet:
https://rstudio.github.io/leaflet/
It will allow you to:
have pop-ups for each shapefile with more data
explicitly set the colour of shapefiles in R, based on data in your dbf file.
use an open map background
Some example code (not all may be relevant):
map <- leaflet()%>%
addTiles(urlTemplate = url, attribution = HTML(attrib))%>%
addPolygons(data = sub_shape,
fill = TRUE,
fillColor = colors$color, #set color here
fillOpacity = .8,
stroke = TRUE,
weight = 3,
color = "white",
dashArray = c(5,5),
popup = pops
)