R Leaflet – Can’t Add WMS Layer

leaflet-rrwms

I am building a Shiny app which should display environmental layers on a Leaflet map, and I'd like some of them to be pulled from the Environment Agency's (UK) WMS service.

I can view the layer in QGIS, but have had no luck doing the same in R Leaflet.

One dataset I'd like to include is Risk of flooding from surface water and you can view the WMS info at:
https://environment.data.gov.uk/spatialdata/risk-of-flooding-from-surface-water-hazard-1-percent-annual-chance/wms?REQUEST=GetCapabilities&SERVICE=WMS

My first attempt has been with addWMSTiles() from leaflet, and then thinking this may not be a tiled service (how can I tell?) I also tried addWMS() from leaflet.extras2 package. Both functions work with examples supplied in the vignettes or by other SO users, but neither works with my layers.

      leaflet() %>% 
        setView(lng = -1.8, lat = 53.6, zoom = 10) %>% 
          addProviderTiles(providers$CartoDB.Positron) %>% 
          
      addWMSTiles("https://environment.data.gov.uk/spatialdata/risk-of-flooding-from-surface-water-hazard-1-percent-annual-chance/wms",
        layers = "Risk_of_Flooding_from_Surface_Water_Hazard_1_percent_annual_chance",
        group = "Leaflet test",
        options = WMSTileOptions(format = "image/png",
                                 info_format = "text/html",
                                 srs = "EPSG:4326",
                                 transparent = TRUE))%>%
          
          addWMS(baseUrl = "https://environment.data.gov.uk/spatialdata/risk-of-flooding-from-surface-water-hazard-1-percent-annual-chance/wms",
                 layers ="Risk_of_Flooding_from_Surface_Water_Hazard_1_percent_annual_chance",
                 group = "Leaflet Extra test",
                 options = WMSTileOptions(
                     transparent = TRUE,
                     format = "image/png",
                     info_format = "text/html")) %>% 

          addLayersControl(overlayGroups = c("Leaflet test", "Leaflet Extra test"))

I only see the background map (whether I preview my app in RStudio or browser):
empty leaflet map

I also tried not setting the WMSTileOptions() at all, and conversely tried to specify the CRS (with srs = "EPSG:4326" which I think from the WMS GetCapabilities should be available). I think I may be specifying the URL or layer name wrong but I can't think what else to do.

For comparison, the QGIS output:
correct QGIS map

Best Answer

It seems that the problem is due to the name of the layer. Replace that by the ordinal number, and your script will work:

leaflet() %>% 
  setView(lng = -1.8, lat = 53.6, zoom = 10) %>% 
  addProviderTiles(providers$OpenStreetMap.Mapnik) %>%
  
  addWMSTiles("https://environment.data.gov.uk/spatialdata/risk-of-flooding-from-surface-water-hazard-1-percent-annual-chance/wms",
              layers = 1,
              group = "Leaflet test",
              options = WMSTileOptions(format = "image/png",
                                       info_format = "text/html",
                                       srs = "EPSG:4326",
                                       transparent = TRUE))%>%
  
  addWMS(baseUrl = "https://environment.data.gov.uk/spatialdata/risk-of-flooding-from-surface-water-hazard-1-percent-annual-chance/wms",
         layers = 1,
         group = "Leaflet Extra test",
         options = WMSTileOptions(
           transparent = TRUE,
           format = "image/png",
           info_format = "text/html")) %>% 
  
  addLayersControl(overlayGroups = c("Leaflet test", "Leaflet Extra test"))
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