Example to Query FDEP ArcGIS REST Server for blue-green algae

ArcGIS_surverEx.R

## Objective: To query FDEP's ArcGIS REST server via R
## You must have server link and know a little about the dataset. 
##
## Due to the query limit and area of interest, query is broken into two regions

### Libraries
library(httr)
library(jsonlite)

path <- 'https://services1.arcgis.com/nRHtyn3uE1kyzoYc/arcgis/rest/services/VIEW_FL_Algal_Bloom_Site_Visits_1/FeatureServer/0/query?'

request <- GET(
  url = path,
  query= list(       
    where = "County='Lee' OR County='Collier' OR County='Hendry' OR County='Glades' OR County='Martin'",
    outFields = '*',
    f = 'pjson'
  )
)
response <- content(request, as = "text", encoding = "UTF-8")
results <- jsonlite::fromJSON(response,flatten=T)

bgdat=results$features;# saves results from last query

request <- GET(
  url = path,
  query= list(       
    where = "County='Okeechobee' OR County='PalmBeach' OR County='Broward' OR County='MiamiDade' OR County='Monroe'",
    outFields = '*',
    f = 'pjson'
  )
)
response <- content(request, as = "text", encoding = "UTF-8")
results <- jsonlite::fromJSON(response,flatten=T)

bgdat=rbind(bgdat, results$features);# combines all results

## Some data cleaning and reformatting
vars=c("attributes.objectid", "attributes.globalid", "attributes.SiteVisitDate", 
       "attributes.Location", "attributes.County", "attributes.Visitor", 
       "attributes.AlgaeObserved", "attributes.SampleTaken", "attributes.DepthDesc", 
       "attributes.SampleDepth", "attributes.AnalyzedBy", "attributes.Otherlab", 
       "attributes.Comments", "attributes.Latitude", "attributes.Longitude", 
       "attributes.AlgalID", "attributes.Microcystin", "attributes.OtherToxin", 
       "attributes.EditDate", "attributes.PicURL", "attributes.ToxinPresent", 
       "attributes.CyanobacteriaDominant", "geometry.x", "geometry.y"
)
vars=strsplit(vars,"\\.")
vars=sapply(vars,"[",2)
colnames(bgdat)<-tolower(vars)

bgdat$sitevisitdate=as.numeric(gsub('000$', '',format(bgdat$sitevisitdate,scientific=F)))
bgdat$datetime=as.POSIXct(bgdat$sitevisitdate,origin = c('1970-01-01'), tz = 'UTC')