add example of a xeno-canto downloader

warbleR_xeno-canto/warbleR_xeno-canto.r

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+library(warbleR)
+
+# Create a new folder inside a new tempdir and set it to your working dir
+wd <- file.path(tempdir(), "xeno-canto_example")
+dir.create(wd)
+setwd(wd)
+
+##
+# Do the queries
+##
+
+# Query xeno-canto for all Phaethornis recordings (e.g., by genus)
+Phae <- query_xc(qword = "Phaethornis", download = FALSE)
+# Check out the structure of resulting the data frame
+str(Phae)
+# Query xeno-canto for all Phaethornis longirostris recordings
+Phae.lon <- query_xc(qword = "Phaethornis longirostris", download = FALSE)
+# Check out the structure of resulting the data frame
+str(Phae.lon)
+
+##
+# filter xeno-canto recordings by quality, signal type and locality
+##
+
+# How many recordings are available for Phaethornis longirostris?
+nrow(Phae.lon)
+# How many signal types exist in the xeno-canto metadata?
+unique(Phae.lon$Vocalization_type)
+# How many recordings per signal type?
+table(Phae.lon$Vocalization_type)
+
+##
+# Filter the metadata to select the signals we want to retain
+##
+
+# First by quality
+Phae.lon <- Phae.lon[Phae.lon$Quality == "A", ]
+nrow(Phae.lon)
+# Then by signal type
+Phae.lon.song <- Phae.lon[grep("song", Phae.lon$Vocalization_type, ignore.case = TRUE), ]
+nrow(Phae.lon.song)
+# Finally by locality
+Phae.lon.LS <- Phae.lon.song[grep("La Selva Biological Station, Sarapiqui, Heredia", Phae.lon.song$Locality, ignore.case = FALSE), ]
+nrow(Phae.lon.LS)
+# Check resulting data frame, 3 recordings remain
+str(Phae.lon.LS)
+# check the location
+map_xc(Phae.lon.LS, img = FALSE)
+
+
+##
+# Once we're sure the recordings fit, it's time to download the files, also save
+# the metadata as .csv file
+##
+
+# Download sound files
+query_xc(X = Phae.lon.LS)
+# Save the metadata object as a .csv file
+write.csv(Phae.lon.LS, "Phae_lon.LS.csv", row.names = FALSE)
+
+##
+# xeno-canto maintains recordings in mp3 format due to file size restrictions.
+# However, we require wav format for all downstream analyses
+##
+
+# here we are downsampling the original sampling rate of 44.1 kHz
+# to speed up downstream analyses in the vignette series
+mp32wav(samp.rate = 22.05)
+# Use checkwavs to see if wav files can be read
+check_wavs()