README.md
In mps9506/aarapir: Access ArcGIS Online Features in R

aarapir

Access ArcGIS online API enpoints with R

aarapir provides an R interface for querying and downloading publically accessible ArcGIS Online feature layers. The primary goal is to provide R users with an easy way to download features from ArcMap Online. I don’t not anticipate this to be a full-fledged API to ArcGIS Online and Enterprise. See the ArcGIS Python API for a more robust access to the ArcGIS API. This is super experimental and likely to change. This project is not associated with or supported by ESRI.

[x] Return mapservice information
[x] Return feature layer information
[x] Return full feature layers (will loop requests if the maximum number of records is limited)
[x] Pass user query so only needed records are returned
[ ] Return image service information
[ ] Provide interface for image or tile data

Download a point feature layer:

library(aarapir)
## Start with a mapserver url, these typically end in "/MapServer"
## Some examples here: https://sampleserver6.arcgisonline.com/arcgis/rest/services

url <- "https://sampleserver6.arcgisonline.com/arcgis/rest/services/WindTurbines/MapServer"

## This returns a list with information from the Map Service
webserver <- service_info(url)

## We can see what feature layers are available to download
webserver$layers
#>   id               name parentLayerId defaultVisibility subLayerIds minScale
#> 1  0 TurbineInspections            -1              TRUE          NA        0
#>   maxScale          type      geometryType
#> 1        0 Feature Layer esriGeometryPoint

## This returns a list with information about the feature layer
## id 0
layerinfo <- layer_info(webserver, 0)

## This downloads the entire feature layer and reads it into a
## simple feature dataframe
dat <- layer_download(layerinfo)
#> Number of target records:  11
dat
#> Simple feature collection with 11 features and 6 fields
#> geometry type:  POINT
#> dimension:      XY
#> bbox:           xmin: -116.6811 ymin: 33.85035 xmax: -116.533 ymax: 33.91881
#> epsg (SRID):    4326
#> proj4string:    +proj=longlat +datum=WGS84 +no_defs
#> First 10 features:
#>    objectid status dateinspected notes photo
#> 1         2     NA  1.295451e+12  test  <NA>
#> 2         6      1 -2.209162e+12        <NA>
#> 3        12     NA            NA  <NA>  <NA>
#> 4        13     NA            NA  <NA>  <NA>
#> 5        14     NA            NA  <NA>  <NA>
#> 6        17     NA            NA        <NA>
#> 7        18     NA            NA        <NA>
#> 8        19     NA            NA        <NA>
#> 9        20     NA            NA        <NA>
#> 10       21     NA            NA        <NA>
#>                                  globalid                   geometry
#> 1  {E41FAF3C-BB03-445F-8E6A-12227C7EC007} POINT (-116.6155 33.86019)
#> 2  {DF9403DA-C08D-4C5C-A505-77A761F296D9}  POINT (-116.533 33.85035)
#> 3  {3EA788B3-32D8-4B1D-8CBC-D1E5757A50DC} POINT (-116.6173 33.91881)
#> 4  {FB929FD4-D75D-419D-B5B9-BDF371F0C34A} POINT (-116.6671 33.87114)
#> 5  {736F24BE-0A10-4779-BD66-71643191087B} POINT (-116.6811 33.91881)
#> 6  {9C4CE3DB-9B5F-4BE6-84E8-3949DF5DA6A4} POINT (-116.5993 33.91736)
#> 7  {CEE9E968-58A5-41D2-BF28-6B14E3997352} POINT (-116.5501 33.91302)
#> 8  {897F8DEF-8C3B-4CB2-88DE-8EA1EF9CD01D} POINT (-116.5407 33.88782)
#> 9  {D4F83D52-C26B-4BEF-A215-D4793B680476} POINT (-116.5773 33.85306)
#> 10 {4FAEBC0C-5060-49D5-B284-54B2F58C2A14} POINT (-116.5846 33.88956)


## If you want to return only objects from a query:
dat <- layer_download(layerinfo, query = "notes = 'test'")
#> Number of target records:  1
## note query support might vary by server, but generally standard query functions
## work. more info: https://gisweb.tceq.texas.gov/arcgis/sdk/rest/index.html#/Query_Map_Service_Layer/02ss0000000r000000/
## enter the query in quoted plain text, the function will do the proper URI encoding
dat
#> Simple feature collection with 1 feature and 6 fields
#> geometry type:  POINT
#> dimension:      XY
#> bbox:           xmin: -116.6155 ymin: 33.86019 xmax: -116.6155 ymax: 33.86019
#> epsg (SRID):    4326
#> proj4string:    +proj=longlat +datum=WGS84 +no_defs
#>   objectid status dateinspected notes photo
#> 1        2   <NA>  1.295451e+12  test  <NA>
#>                                 globalid                   geometry
#> 1 {E41FAF3C-BB03-445F-8E6A-12227C7EC007} POINT (-116.6155 33.86019)

Downloading mosaiced images works. I’m having difficulty finding maps that allow downloading source rasters even though it is supported by the API. This is definately going to change.

url <- "https://landsat2.arcgis.com/arcgis/rest/services/Landsat8_Views/ImageServer"
webserver <- service_info(url)
r1 <- image_download(webserver,
                     size = "800,500",)
r1
#> class      : RasterBrick 
#> dimensions : 500, 800, 4e+05, 11  (nrow, ncol, ncell, nlayers)
#> resolution : 50093.77, 50093.77  (x, y)
#> extent     : -20037507, 20037508, -12524893, 12521991  (xmin, xmax, ymin, ymax)
#> crs        : +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs 
#> source     : C:/Users/michael.schramm/AppData/Local/Temp/RtmpILzp8W/ras12c456bc427c.tiff 
#> names      : ras12c456bc427c.1, ras12c456bc427c.2, ras12c456bc427c.3, ras12c456bc427c.4, ras12c456bc427c.5, ras12c456bc427c.6, ras12c456bc427c.7, ras12c456bc427c.8, ras12c456bc427c.9, ras12c456bc427c.10, ras12c456bc427c.11 
#> min values :            -32768,            -32768,            -32768,            -32768,            -32768,            -32768,            -32768,            -32768,            -32768,             -32768,             -32768 
#> max values :             32767,             32767,             32767,             32767,             32767,             32767,             32767,             32767,             32767,              32767,              32767
raster::plotRGB(r1, r = 4, g = 3, b = 2, stretch = "lin",
                bgalpha = 0)