Package 'arcpullr'

arcpullr

Description

A package for pulling spatial data from an ArcGIS REST API

Details

The role of the arcpullr package is simple...to pull spatial data from an ArcGIS REST API. These APIs are housed by various different agencies, organizations, entitites, etc., but allow a consistent format for storing and retrieving spatial data

get_spatial_layer

This function makes up the core of the package. It allows users to pull spatial data given a URL of an ArcGIS REST API. There are many additional query parameters that can (and probably should) be added; however, we've simplified many of these out for you with the functions below.

get_layer_by_spatial family of functions

These functions allow you to pull layers using a spatial query. The abstract syntax is wrapped into the functions, so all you have to do is pass these functions an sf object of the spatial area, line, or point you want to query by. These functions include get_layer_by_poly, get_layer_by_point, get_layer_by_line, get_layer_by_multipoint, and get_layer_by_envelope. It should be fairly obvious what type of spatial layer each function takes with the exception of get_layer_by_envelope except that it isn't particularly useful for a single point.

get_image_layer

This is one of the core functions of the package. It retrieves image service layers from an ArcGIS REST API designated by the URL

get_map_layer

This is one of the core functions of the package. It retrieves map service layers from an ArcGIS REST API designated by the URL

Helper functions

There are a few utility functions to help you along the way. The first is plot_layer, which is a useful way to plot the spatial layer you've tried to pull just to make sure it works. If you want fancier maps you'd be better served with ggplot2 or tmaps, though.

Other helpers include the sf_objects functions, which allow you to easily create sf points, lines, and polygons with a few coordinates.

Lastly, there is a sql_where function to help aid in building more complex SQL WHERE clauses used to query by the where argument in the retrieval functions above.

---

Various URLs used in examples

Description

These are URLs that are used for examples throughout the package

Usage

reykjanes_lava_flow_url

wi_hydro_url

wi_landcover_url

wi_leaf_off_url

Format

Character strings of URLs

An object of class character of length 1.

An object of class character of length 1.

An object of class character of length 1.

---

Convert coordinates from an 'sf' object to formatted well-known text

Description

Use this function to convert the coordinates of a sf polygon object to a string of well known text. The output can be passed to an ArcGIS REST API to perform a spatial query.

Usage

format_polygon_coords(sf_obj)

format_line_coords(sf_obj)

format_multipoint_coords(sf_obj)

format_point_coords(sf_obj)

format_envelope_coords(sf_obj)

format_coords(sf_obj, geom_type)

Arguments

sf_obj	An sf object
geom_type	Either "points", "paths", or "rings". Choose wisely

Details

Spatial queries from an ArcGIS REST API require specific text inputs formatted in a way called well-known text (WKT). ArcGIS REST APIs have their own syntax for how the text is taken. These functions will format sf objects in the correct way to be able to make spatial queries from a ArcGIS REST API

Value

String of well known text

Examples

mke_polygon_coords <- format_polygon_coords(mke_county)

---

Get Geometry Type

Description

Get Geometry Type

Usage

get_geometry_type(url)

Arguments

url	A character string of a feature services URL

Value

A character string of the layers geometry type

Examples

## Not run: 
get_geometry_type(reykjanes_lava_flow_url)

## End(Not run)

---

Retrieve an image service layer from an ArcGIS REST API

Description

This function retrieves image service layers from an ArcGIS REST services API and returns them as a RasterStack object

Usage

get_image_layer(
  url,
  sf_object = NULL,
  bbox = NULL,
  bbox_crs = NULL,
  token = "",
  clip_raster = TRUE,
  format = "png",
  transparent = TRUE,
  ...
)

Arguments

url	A character string of the url for the layer to pull
sf_object	An sf object used for the bounding box
bbox	Vector of bounding box coordinates
bbox_crs	CRS for bbox (required if bbox is used)
token	A character string of the token (if needed)
clip_raster	Logical. Should the raster be clipped to contain only the pixels that reside in the sf_object? By default, ArcGIS returns some overlapping edge pixels. Setting clip_raster to TRUE (default) will remove these using mask from the raster package
format	The raster format desired. Default is "png"
transparent	Logical. Retrieve a raster with a transparent background (TRUE, default) or not (FALSE)
...	Additional arguments to pass to the ArcGIS REST API

Details

This is one of the core functions of the package. It retrieves image service layers from an ArcGIS REST API designated by the URL. These layers require a bounding box to query the map layer, which is either taken from the sf_object argument or optionally can be passed via the bbox argument. Either sf_object or bbox are optional, but one of them must be present.

All of the querying parameters are sent via a POST request to the URL, so if there are issues with passing additional parameters via ... first determine how they fit into the POST request and make adjustments as needed. This syntax can be tricky if you're not used to it.

Value

A "RasterStack" object

Examples

## Not run: 
wi_leaf_off_layer <- get_image_layer(wi_leaf_off_url, wis_poly)
plot_layer(wi_leaf_off_layer, outline_poly = wis_poly)

## End(Not run)

---

Pull the HTML body from a web page

Description

Used internally to pull HTML for a layer's web page so that the call doesn't have to be made twice in get_geometry_type if the url provided there is for a raster layer.

Usage

get_layer_html(url)

Arguments

url	Character. The URL of the web page

Value

A character string of the HTML body

---

Retrieve metadata for a layer

Description

This function retrieves metadata for a layer.

Usage

get_layer_info(url, token = "")

Arguments

url	A character string of the url for the layer to pull
token	A character string of the token (if needed)

Value

A list of metadata fields

Examples

## Not run: 
# lava flows on Reykjanes (pr. 'rake-yah-ness') peninsula in Iceland
lava_flows_info <- get_layer_info(reykjanes_lava_flow_url)

## End(Not run)

---

Returns a legend for a raster layer

Description

Raster layers are accompanied with legends to identify what the colors mean. This function retrieves those legend values and returns them as a data.frame with the associated RGB color values. This will likely be most useful for plotting and analysis of map layers.

Usage

get_layer_legend(url)

Arguments

url	A URL to a Map or Image Service layer

Value

A data.frame with two columns (color, values) and the number of rows equal to the number of values in a layer

Examples

## Not run: 
get_layer_legend(wi_landcover_url)

## End(Not run)

---

Retrieve ArcGIS REST API spatial layer by spatial query

Description

These functions are wrappers around get_spatial_layer that are specialized for querying by a spatial layer. They will make a POST request to the query URL which returns data (if available) based on the appropriate spatial feature (geometry) and relationship (sp_rel).

Usage

get_layer_by_poly(url, geometry, sp_rel = "contains", ...)

get_layer_by_line(url, geometry, sp_rel = "intersects", ...)

get_layer_by_point(url, geometry, sp_rel = "intersects", ...)

get_layer_by_multipoint(url, geometry, sp_rel = "intersects", ...)

get_layer_by_envelope(url, geometry, sp_rel = "intersects", ...)

get_layer_by_spatial(
  url,
  geometry,
  geom_type,
  sp_ref = NULL,
  sp_rel = "intersects",
  ...
)

Arguments

url	A character string of the url for the layer to pull
geometry	An sf object used for the spatial query
sp_rel	Character. The type of relationship to query by. Possible options include "intersects", "contains", and "crosses"
...	Additional arguements to pass to get_spatial_layer
geom_type	A character of the geometry type to be used. This param is automatically specified in all get_layer_by_* functions except get_spatial_layer
sp_ref	The spatial reference value

Value

An object of class "sf" of the appropriate layer

Examples

## Not run: 
  mke_waters <- get_layer_by_poly(wi_hydro_url, mke_county)

## End(Not run)

---

Retrieve a map service layer from an ArcGIS REST API

Description

This function retrieves map service layers from an ArcGIS REST services API and returns them as a RasterLayer object

Usage

get_map_layer(
  url,
  sf_object = NULL,
  bbox = NULL,
  bbox_crs = NULL,
  token = "",
  clip_raster = TRUE,
  format = "png",
  transparent = TRUE,
  add_legend = TRUE,
  ...
)

Arguments

url	A character string of the url for the layer to pull
sf_object	An sf object used for the bounding box
bbox	Vector of bounding box coordinates
bbox_crs	CRS for bbox (required if bbox is used)
token	A character string of the token (if needed)
clip_raster	Logical. Should the raster be clipped to contain only the pixels that reside in the sf_object? By default, ArcGIS returns some overlapping edge pixels. Setting clip_raster to TRUE (default) will remove these using mask from the raster package
format	The raster format desired. Default is "png"
transparent	Logical. Retrieve a raster with a transparent background (TRUE, default) or not (FALSE)
add_legend	Logical. Pull legend and match to color values (TRUE, default) or not (FALSE)
...	Additional arguments to pass to the ArcGIS REST API

Details

This is one of the core functions of the package. It retrieves map service layers from an ArcGIS REST API designated by the URL. These layers require a bounding box to query the map layer, which is either taken from the sf_object argument or optionally can be passed via the bbox argument. Either sf_object or bbox are optional, but one of them must be present.

All of the querying parameters are sent via a POST request to the URL, so if there are issues with passing additional parameters via ... first determine how they fit into the POST request and make adjustments as needed. This syntax can be tricky if you're not used to it.

Value

A "RasterLayer" object

Examples

## Not run: 
wi_landcover<- get_map_layer(wi_landcover_url, wis_poly)
plot_layer(wi_landcover, outline_poly = wis_poly)

## End(Not run)

---

Pull a raster layer from a map service or image service layer of an ArcGIS REST API

Description

This is an internal function to pull raster layers from either a map service or an image service of an ArcGIS REST API. This function is the engine that drives get_map_layer and get_image_layer

Usage

get_raster_layer(
  url,
  sf_object = NULL,
  bbox = NULL,
  bbox_crs = NULL,
  token = "",
  clip_raster = TRUE,
  format = "png",
  transparent = TRUE,
  export_type = "map",
  add_legend = FALSE,
  ...
)

Arguments

url	A character string of the url for the layer to pull
sf_object	An sf object used for the bounding box
bbox	Vector of bounding box coordinates
bbox_crs	CRS for bbox (required if bbox is used)
token	A character string of the token (if needed)
clip_raster	Logical. Should the raster be clipped to contain only the pixels that reside in the sf_object? By default, ArcGIS returns some overlapping edge pixels. Setting clip_raster to TRUE (default) will remove these using mask from the raster package
format	The raster format desired. Default is "png"
transparent	Logical. Retrieve a raster with a transparent background (TRUE, default) or not (FALSE)
export_type	Character. Either "map" or "image" for the respective service layer desired
add_legend	Logical. Pull legend and match to color values (TRUE, default) or not (FALSE)
...	Additional arguments to pass to the ArcGIS REST API

Value

An object of type RasterLayer if export_type = "map" or an object of type RasterStack if export_type = "image"

---

Get elements of a Service or Layer from an ArcGIS REST endpoint

Description

This family of functions is meant to pull attributes from a particular service or layer hosted on an ArcGIS REST API. If the service is an ImageServer or MapServer, then the behavior will be slightly different than for a Feature Layer (see details).

Usage

get_service_type(url, ...)

Arguments

url	A character string of a valid layer URL
...	Only used internally, but html can be passed

Details

get_service_type will return the type of service or layer for the respective URL (or html) that is passed to the function. For a feature layer the function should return "feature_layer", for a Image or Map Server the function will return "image" or "map", respectively.

get_geometry_type will return the geometry type of feature service layers housed on an ArcGIS REST API server. If a URL is provided that points to a map or image layer the function will return an error (i.e. only feature layers have geometry types).

get_supported_operations will simply return a character vector that lists the supported operations for url.

Value

A character string defining the layer type

Examples

## Not run: 
get_service_type(reykjanes_lava_flow_url)

## End(Not run)

---

Return CRS value of an sf object

Description

Return CRS value of an sf object

Usage

get_sf_crs(sf_obj)

Arguments

sf_obj

An object of class sf

Value

A numeric value referring to the coordinate reference system

Examples

get_sf_crs(iceland_poly)

---

Retrieve a feature service layer from an ArcGIS REST API

Description

This function retrieves spatial layers present in Feature Service layers of an ArcGIS REST services API and returns them as an sf object

Usage

get_spatial_layer(
  url,
  out_fields = c("*"),
  where = "1=1",
  token = "",
  sf_type = NULL,
  head = FALSE,
  ...
)

Arguments

url	A character string of the url for the layer to pull
out_fields	A character string of the fields to pull for each layer
where	A character string of the where condition. Default is 1=1
token	A character string of the token (if needed)
sf_type	A character string specifying the layer geometry to convert to sf ("esriGeometryPolygon", "esriGeometryPoint", "esriGeometryPolyline"), if NULL (default) the server will take its best guess
head	Logical or numeric. Limits the number of records returned from a query. If TRUE, only the first 5 records will be returned. If numeric, then the number of records specified in head will be returned
...	Additional arguments to pass to the ArcGIS REST POST request (or associated internal functions used to query them)

Details

This is one of the core functions of this package. It retrieves spatial layers from feature services of an ArcGIS REST API designated by the URL. Additional querying features can be passed such as a SQL WHERE statement (where argument) or spatial queries as well as any other types of queries that the ArcGIS REST API accepts (using ...). However, for easier spatial querying see get_layers_by_spatial.

All of the querying parameters are sent via a POST request to the URL, so if there are issues with passing additional parameters via ... first determine how they fit into the POST request and make adjustments as needed. This syntax can be tricky if you're not used to it.

Value

An object of class "sf" of the appropriate layer

Examples

## Not run: 
# lava flows on Reykjanes (pr. 'rake-yah-ness') peninsula in Iceland
lava_flows <- get_spatial_layer(reykjanes_lava_flow_url)
plot_layer(lava_flows, outline_poly = reykjanes_poly)
plot_layer(lava_flows, outline_poly = iceland_poly)

## End(Not run)

---

Retrieve a table from an ArcGIS REST API

Description

This function retrieves tables present in an ArcGIS REST services API and returns them as a data frame.

Usage

get_table_layer(
  url,
  out_fields = "*",
  where = "1=1",
  token = "",
  head = FALSE,
  ...
)

Arguments

url	A character string of the url for the layer to pull
out_fields	A character string of the fields to pull for each layer
where	A character string of the where condition. Default is 1=1
token	A character string of the token (if needed)
head	Logical or numeric. Limits the number of records returned from a query. If TRUE, only the first 5 records will be returned. If numeric, then the number of records specified in head will be returned
...	Additional arguments to pass to the ArcGIS REST POST request (or associated internal functions used to query them)

Details

This function retrieves tables from an ArcGIS REST API designated by the URL. Additional querying features can be passed such as a SQL WHERE statement (where argument) as well as any other types of queries that the ArcGIS REST API accepts (using ...).

All of the querying parameters are sent via a POST request to the URL, so if there are issues with passing additional parameters via ... first determine how they fit into the POST request and make adjustments as needed. This syntax can be tricky if you're not used to it.

Value

A data frame of the appropriate layer

---

Match colors in RasterLayer color space to the provided legend values

Description

Colors provided by the legend do not always correspond exactly with the colors in the colortable of a RasterLayer object. They are usually pretty close, though, so this function finds the closest colors, maps them to the appropriate colors in the Raster* object, and applies that to the legend.

Usage

match_raster_colors(legend, x)

Arguments

legend	An object of class raster_legend as returned by get_layer_legend
x	A RasterLayer object as returned by get_map_layer

Details

Raster colors in x are mapped to those in legend by converting the RGB hexadecimal values to a 3D vector of values for red, green and blue. The closest values are then assigned using 3D Pythagorean theorem to compute the distance among all colors. The minimum distance in three dimensional space is the color in x that gets mapped to the appropriate color in legend.

Value

A raster_legend object with corrected colors to match those in x

Examples

## Not run: 
wi_landcover <- get_map_layer(wi_landcover_url, wis_poly)
legend <- get_layer_legend(wi_landcover_url)
new_legend <- match_raster_colors(legend, wi_landcover_url)

## End(Not run)

---

Plot a spatial layer

Description

This function plots a spatial layer as returned from get_spatial_layer.

Usage

plot_layer(x, ...)

plot_layer.sf(
  x,
  outline_poly = NULL,
  outline_size = 1.2,
  outline_color = "gray30",
  plot_pkg = "ggplot",
  ...
)

Arguments

x	An sf or Raster* object as returned from a get_*_layer function
...	Additional arguments to plot_layer
outline_poly	Optional. An sf polygon to outline sf_data for context
outline_size	Numeric argument that controls width of parameter
outline_color	A character vector of a valid color
plot_pkg	Character. The plotting environment to use. Either "ggplot" (default) or "base"

Value

Either a ggplot object, or simply plots x if plot_pkg = "base"

Examples

## Not run: 
plot_layer(iceland_poly)
plot_layer(portage_county, outline_poly = wis_poly)

## End(Not run)

---

Plot a RasterBrick object

Description

Plot a RasterBrick object

Usage

## S4 method for signature 'RasterBrick'
plot_layer(
  x,
  outline_poly = NULL,
  outline_size = 1.2,
  outline_color = "gray30",
  plot_pkg = "ggplot",
  ...
)

Arguments

x	An sf or Raster* object as returned from a get_*_layer function
outline_poly	Optional. An sf polygon to outline sf_data for context
outline_size	Numeric argument that controls width of parameter
outline_color	A character vector of a valid color
plot_pkg	Character. The plotting environment to use. Either "ggplot" (default) or "base"
...	Additional arguments to plot_layer

Examples

## Not run: 
wi_aerial <- get_map_layer(wi_leaf_off_url, wis_poly)
plot_layer(wi_aerial, outline_poly = wis_poly)

## End(Not run)

---

Plot a RasterLayer object

Description

Plot a RasterLayer object

Usage

## S4 method for signature 'RasterLayer'
plot_layer(
  x,
  outline_poly = NULL,
  outline_size = 1.2,
  outline_color = "gray30",
  legend = TRUE,
  plot_pkg = "ggplot",
  ...
)

Arguments

x	An sf or Raster* object as returned from a get_*_layer function
outline_poly	Optional. An sf polygon to outline sf_data for context
outline_size	Numeric argument that controls width of parameter
outline_color	A character vector of a valid color
legend	Logical. Only valid when plotting RasterLayers retrieved from get_map_layer where legend was also retrieved
plot_pkg	Character. The plotting environment to use. Either "ggplot" (default) or "base"
...	Additional arguments to plot_layer

Examples

## Not run: 
wi_landcover <- get_map_layer(wi_landcover_url, wis_poly)
plot_layer(wi_landcover, outline_poly = wis_poly)

## End(Not run)

---

Plot a RasterStack object

Description

Plot a RasterStack object

Usage

## S4 method for signature 'RasterStack'
plot_layer(
  x,
  outline_poly = NULL,
  outline_size = 1.2,
  outline_color = "gray30",
  plot_pkg = "ggplot",
  ...
)

Arguments

x	An sf or Raster* object as returned from a get_*_layer function
outline_poly	Optional. An sf polygon to outline sf_data for context
outline_size	Numeric argument that controls width of parameter
outline_color	A character vector of a valid color
plot_pkg	Character. The plotting environment to use. Either "ggplot" (default) or "base"
...	Additional arguments to plot_layer

Examples

## Not run: 
wi_aerial <- get_map_layer(wi_leaf_off_url, wis_poly)
plot_layer(wi_aerial, outline_poly = wis_poly)

## End(Not run)

---

Plot an sf object

Description

Plot an sf object

Usage

## S4 method for signature 'sf'
plot_layer(
  x,
  outline_poly = NULL,
  outline_size = 1.2,
  outline_color = "gray30",
  plot_pkg = "ggplot",
  ...
)

Arguments

x	An sf or Raster* object as returned from a get_*_layer function
outline_poly	Optional. An sf polygon to outline sf_data for context
outline_size	Numeric argument that controls width of parameter
outline_color	A character vector of a valid color
plot_pkg	Character. The plotting environment to use. Either "ggplot" (default) or "base"
...	Additional arguments to plot_layer

Examples

## Not run: 
plot_layer(wis_poly)

## End(Not run)

---

Convert RasterLayer into data.frame of colors for each pixel that can be used for plotting

Description

This function is used internally by plot_layer to convert a Raster* object to a data.frame of colors for each pixel that can be used for plotting with ggplot2

Usage

raster_colors(x)

Arguments

x	A Raster* object

Value

A data.frame with 3 columns and length(raster_object) rows. Two of these columns are the x-y coordinates of each pixel, and one is a value for color that can be used for plotting

Examples

## Not run: 
wi_landcover <- get_map_layer(wi_landcover_url, wis_poly)
wi_landcover_data <- raster_colors(wi_landcover)
head(wi_landcover_data)

## End(Not run)

---

Convert RasterBrick into data.frame of colors that can be used for plotting

Description

This function is used internally by plot_layer to convert a RasterBrick object to a data.frame of colors for each pixel that can be used for plotting with ggplot2. Note that this function assumes that the first three bands in the RasterBrick objects are the RGB values and all additional bands are ignored.

Usage

## S4 method for signature 'RasterBrick'
raster_colors(x)

Arguments

x	A RasterBrick object

Value

A data.frame with 3 columns and length(raster_object) rows

Examples

## Not run: 
wi_leaf_off_layer <- get_image_layer(wi_leaf_off_url, wis_poly)
wi_leaf_off_data <- raster_colors(wi_leaf_off_layer)

## End(Not run)

---

Convert RasterLayer into data.frame of colors that can be used for plotting

Description

This function is used internally by plot_layer to convert a RasterLayer object to a data.frame of colors for each pixel that can be used for plotting with ggplot2

Usage

## S4 method for signature 'RasterLayer'
raster_colors(x)

Arguments

x	A RasterLayer object

Value

A data.frame with 3 columns and length(raster_object) rows

Examples

## Not run: 
wi_landcover <- get_map_layer(wi_landcover_url, wis_poly)
wi_landcover_data <- raster_colors(wi_landcover)

## End(Not run)

---

Convert RasterStack into data.frame of colors that can be used for plotting

Description

This function is used internally by plot_layer to convert a RasterStack object to a data.frame of colors for each pixel that can be used for plotting with ggplot2. Note that this function assumes that the first three bands in the RasterStack objects are the RGB values and all additional bands are ignored.

Usage

## S4 method for signature 'RasterStack'
raster_colors(x)

Arguments

x	A RasterStack object

Value

A data.frame with 3 columns and length(raster_object) rows

Examples

## Not run: 
wi_leaf_off_layer <- get_image_layer(wi_leaf_off_url, wis_poly)
wi_leaf_off_data <- raster_colors(wi_leaf_off_layer)

## End(Not run)

---

Various example sf polygons

Description

These are sf polygons that are used for examples throughout the package

Usage

iceland_poly

mke_county

portage_county

reykjanes_poly

wis_counties

wis_poly

cook_creek_ws

cook_creek_streams

cook_creek_env

mke_river

poly_streams_contains

poly_streams_crosses

sugar_creek

sugar_creek_env

trout_hab_project_pt

trout_hab_project_pts

example_poly

trout_hab_project_pts

Format

An object of class sf and data.frame:

An object of class sf (inherits from data.frame) with 1 rows and 3 columns.

An object of class sf (inherits from data.frame) with 1 rows and 3 columns.

An object of class sf (inherits from data.frame) with 1 rows and 2 columns.

An object of class sf (inherits from data.frame) with 72 rows and 3 columns.

An object of class sf (inherits from data.frame) with 1 rows and 2 columns.

An object of class sf (inherits from data.frame) with 1 rows and 7 columns.

An object of class sf (inherits from tbl_df, tbl, data.frame) with 5 rows and 3 columns.

An object of class sf (inherits from tbl_df, tbl, data.frame) with 10 rows and 3 columns.

An object of class sf (inherits from tbl_df, tbl, data.frame) with 5 rows and 5 columns.

An object of class sf (inherits from data.frame) with 1 rows and 28 columns.

An object of class sf (inherits from data.frame) with 4 rows and 28 columns.

An object of class sf (inherits from data.frame) with 7 rows and 28 columns.

An object of class sf (inherits from data.frame) with 15 rows and 28 columns.

An object of class sf (inherits from data.frame) with 1 rows and 11 columns.

An object of class sf (inherits from data.frame) with 4 rows and 11 columns.

An object of class sf (inherits from data.frame) with 1 rows and 1 columns.

An object of class sf (inherits from data.frame) with 4 rows and 11 columns.

Source

ggplot2's map_data and Wisconsin DNR ArcGIS REST API

---

Various example raster objects

Description

These are raster objects that are used for examples throughout the package

Usage

wi_landcover

wi_aerial_imagery

Format

An object of class RasterLayer of dimension 400 x 400 x 1.

An object of class RasterBrick of dimension 400 x 400 x 3.

Source

Wisconsin DNR ArcGIS Image Server

---

Create sf objects from coordinates

Description

These are simple wrapper functions for creating sf objects from points

Usage

sf_line(..., crs = 4326)

sf_point(..., crs = 4326)

sf_points(..., crs = 4326)

sf_polygon(..., crs = 4326)

sf_box(xmin, ymin, xmax, ymax, crs = 4326)

Arguments

...	The coordinates of the object
crs	The coordinate reference system. Defaults to 4326
xmin, xmax, ymin, ymax	Corners for sf_box

Value

An sf object of the appropriate type

Examples

pt_a <- c(-90, 45)
pt_b <- c(-89, 44)
pt <- sf_points(pt_a)
line <- sf_line(pt_a, pt_b)

---

Spatial relationship descriptor and lookup tables

Description

These data.frames are used to lookup and explain which spatial relation types go with different spatial queries.

Usage

sp_rel_valid

sp_rel_lookup

Format

sp_rel_valid is a data.frame with 105 rows and 3 variables as follows:

feature_class

A feature class to be queried

query_feature_class

The feature class used to do a spatial query

sp_rel

The spatial relationships that are valid for the feature class and query_feature_class combination

sp_rel_lookup is a data.frame with 9 rows and 2 variables as follows:

sp_rel

The spatial relationship being described

description

A description of the sp_rel

Details

sp_rel_lookup explains the various different types of spatial relationships available through ArcGIS REST APIs. sp_rel_valid shows which spatial relationships are valid with different geometry types being queried and used to do spatial queries

Source

sp_rel_valid–Independent tests done specifically by and for arcpullr

sp_rel_lookup – https://help.arcgis.com/en/webapi/wpf/apiref/ESRI.ArcGIS.Client~ESRI.ArcGIS.Client.Tasks.SpatialRelationship.html

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Lookup function for shorthand versions of spatial relation text strings

Description

After typing "esriSpatialRelIntersects" into 4 to 5 functions, you'll get pretty sick of typing that. This function serves to allow shorthand strings to be passed to the sp_rel arguments of the get_layers_by_spatial family of functions. For example, you can pass "intersects" to this function and it will return "esriSpatialRelIntersects"

Usage

sp_rel_xref(x)

Arguments

x	A character string. One of "contains", "crosses", "envelopeintersects", "indexintersects", "intersects", "overlaps", "relation", "touches", "within"

Value

The appropriately named ESRI version of x. For example, an x value of "intersects" returns "esriSpatialRelIntersects"

Examples

sp_rel_xref("intersects")

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Format a SQL where clause from arguments

Description

This function will create a where statement that is compatible with get_spatial_layer). This statement can then be passed to the where argument in this function.

Usage

sql_where(..., rel_op = "=")

Arguments

...	Named objects to be queried by
rel_op	Character. The relational operator in the SQL clause (i.e. "=", "IN", "NOT IN", etc.). If a single rel_op is provide with multiple ... parameters then it will be recycled length(...) times.

Value

A character string that can be passed to the where argument of get_spatial_layer

Examples

## Not run: 
wbics <- sql_where(WATERBODY_WBIC = c(805400, 804600), rel_op = "IN")
lakes <- get_spatial_layer(wi_hydro_url, where = wbics)
plot_layer(lakes)

## End(Not run)

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Check to see which spatial relation types are applicable to the feature classes being queried and the sf objects use do to a spatial query

Description

Check to see which spatial relation types are applicable to the feature classes being queried and the sf objects use do to a spatial query

Usage

valid_sp_rel(fc1, fc2, pull = TRUE)

Arguments

fc1	Character. The feature class type being queried. Available options are "point", "multipoint", "line", or "area".
fc2	Character. The geometry type of the sf object used to do a spatial query. Available options are "point", "multipoint", "line", or "area".
pull	Logical. Pull the available options (TRUE) or print all columns of the sp_rel_valid data.frame for the appropriate fc1 and fc2

Value

Either a vector or filtered data.frame showing the appropriate sp_rels for the given feature classes

Examples

valid_sp_rel("line", "line")

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