Map biodiversity records with rgbif, maps and ggplot2 packages in R

9 Jul

Global Biodiversity Information Facility or GBIF is an international consortium working towards making Biodiversity information available through single portal to everyone.  GBIF with its partners are working towards mobilizing data, developing data and metadata standards, developing distributed database system and making the data accessible through APIs. At this point this largest single window data source covering wide spectrum of taxa and geographic range.

rgbif is a package in R to download the data from GBIF data portal using its API. Once the data is available as data frame in R, we can use several functions and packages to analyse and visualize it. [ Cran, rOpenSci, my work ]

Here first we use occurrencelist function to download 1000 records (maxresults = 1000) for “Danaus plexipus”  (sciname = ‘Danaus plexippus’) which is Monarch Butterfly. We specify that we want records that have been geo-coded (coordinatestatus=TRUE), we want it to be stored in data frame (latlongdf=TRUE) and we want to remove any records that have zeros in Latitude and Longitude values (removeZeros = TRUE). This command will result in a data frame dan_ple with monarch occurrence records.

Now we use map_data function form maps package to get world map. Use ggplot function form ggplot2 package to plot the world map as polygon layer. On top of that we plot the Monarch butterfly occurrence points using decimalLatitude and decimalLongitude columns in red color. and specify the title of the map.

dan_ple=occurrencelist(sciname = 'Danaus plexippus', 
                       coordinatestatus = TRUE, maxresults = 1000, 
                       latlongdf = TRUE, removeZeros = TRUE)
world = map_data("world")
ggplot(world, aes(long, lat)) +
geom_polygon(aes(group = group), fill = "white", 
              color = "gray40", size = .2) +
geom_jitter(data = dan_ple,
aes(decimalLongitude, decimalLatitude), alpha=0.6, 
             size = 4, color = "red") +
opts(title = "Danaus plexippus")

The final output of the code snippet is as following.

Map of Danaus plexippus

More maps using other packages to come soon.

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