Spatial Queries

To see more complete package documentation check out: https://pfrater.github.io/arcpullr/

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ArcGIS REST API’s may be spatially queried using the get_layer_by_* family of functions. These functions require a spatial object of class sf (i.e. of the R package sf: Simple Features for R) and a Spatial Relationship to be passed to the geometry and sp_rel arguments respectively.

The package contains five functions that can be used to perform spatial queries:

• get_layer_by_line

• get_layer_by_point

• get_layer_by_polygon

• get_layer_by_multipoint

• get_layer_by_envelope

  URL’s for examples

  Example Source Data

  
  #WDNR Server
  server <- "https://dnrmaps.wi.gov/arcgis/rest/services/"
  server2 <- "https://dnrmaps.wi.gov/arcgis2/rest/services/"
  
  #River URL
  layer <- "TS_AGOL_STAGING_SERVICES/EN_AGOL_STAGING_SurfaceWater_WTM/MapServer/2"
  river_url <- paste0(server2,layer)
  
  #Country URL 
  layer <- "DW_Map_Dynamic/EN_Basic_Basemap_WTM_Ext_Dynamic_L16/MapServer/3"
  county_url <- paste0(server,layer)
  
  #Trout URL 
  layer <- "FM_Trout/FM_TROUT_HAB_SITES_WTM_Ext/MapServer/0"
  trout_url <- paste0(server,layer)
  
  #Watershed URL
  layer <- "WT_SWDV/WT_Federal_Hydrologic_Units_WTM_Ext/MapServer/0"
  watershed_url <- paste0(server,layer)
  
  #get layers for queries
  mke_river <- get_spatial_layer(
    river_url, 
    where = "RIVER_SYS_NAME = 'Milwaukee River'"
  )
  
  trout_hab_project_pts <- get_spatial_layer(
    trout_url,
    where = "WATERBODYNAMECOMBINED = 'Sugar Creek' and FISCALYEAR = 2017"
  )
  
  trout_hab_project_pt <- trout_hab_project_pts[1, ]
  
  # get watershed layer for Cook Creek
  cook_creek_ws <- get_spatial_layer(
    watershed_url,
    where = "HUC12_NAME = 'Cook Creek'"
  )

  
  

  get_layer_by_line

  The get_layer_by_line function uses A LINSESTRING or MULTILINESTRING sf object to query an ArcGIS REST API. The below example uses a MULTILINESTRING sf object of the Milwaukee River to query the Wisconsin County polygon layer.

  mke_river_counties <- get_layer_by_line(url = county_url, geometry = mke_river)
  plot_layer(mke_river, outline_poly = mke_river_counties)