Kyle Onda ksonda

https://labs.waterdata.usgs.gov/sta/v1.1/Locations?$filter=properties/mainstemURL%20eq%20%27https://geoconnex.us/ref/mainstems/29559%27&$expand=Things($select=id)/Datastreams($filter=properties/ParameterCode%20eq%20%2700065%27)/Observations($top=1)&$resultFormat=GeoJSON"

https://labs.waterdata.usgs.gov/sta/v1.1/Locations?$filter=properties/mainstemURL%20eq%20%27https://geoconnex.us/ref/mainstems/29559%27&$expand=Things($select=id)/Datastreams($filter=properties/ParameterCode%20eq%20%2700065%27)/Observations($top=1)&$resultFormat=GeoJSON"

	---
	title: "Using the geoconnex Reference Feature Server with R"
	format:
	html:
	page-layout: full
	---

	Below we demonstrates how to use the geoconnex reference feature server API with R's spatial packages, particularly `sf`. We'll explore various use cases for working with hydrological and related spatial data.

	PREFIX schema: <https://schema.org/>
	PREFIX gsp: <http://www.opengis.net/ont/geosparql#>
	PREFIX wiki: <https://www.wikidata.org/wiki/>
	PREFIX hyf: <https://www.opengis.net/def/schema/hy_features/hyf/>
	PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

	SELECT ?dataset ?variableName ?temporalCoverage WHERE {
	# Bind the @id of the mainstem of interest
	BIND(<https://geoconnex.us/ref/mainstems/1009561> AS ?mainstem)

	{
	"type": "CoverageCollection",
	"domainType": "PointSeries",
	"parameters": {
	"discharge": {
	"type": "Parameter",
	"description": {"en":"Water discharge in cubic feet per second"},
	"observedProperty": {
	"label": {"en":"Discharge"},
	"id": "http://waterdata.usgs.gov/nwisweb/rdf?parmCd=00060"

	<gml:FeatureCollection
	xmlns:gml="http://www.opengis.net/gml/3.2"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:wml2="http://www.opengis.net/waterml/2.0"
	xmlns:xlink="http://www.w3.org/1999/xlink"
	xmlns:om="http://www.opengis.net/om/2.0"
	xmlns:sa="http://www.opengis.net/sampling/2.0"
	xmlns:sams="http://www.opengis.net/samplingSpatial/2.0"
	xmlns:swe="http://www.opengis.net/swe/2.0" gml:id="USGS.waterservices" xsi:schemaLocation="http://www.opengis.net/waterml/2.0 http://schemas.opengis.net/waterml/2.0/waterml2.xsd">
	<gml:featureMember>


	library(sf)
	library(mapview)

	# read identifiers for Colorado River and Colorado River (TX) into simple features
	colorado_river <- sf::read_sf("https://geoconnex.us/ref/mainstems/29559")
	colorado_river_tx <- sf::read_sf("https://geoconnex.us/ref/mainstems/2639515")


	## Function that constructs query to retrive the latest discharge observation from the USGS

	##packages used
	require(sf)
	require(SPARQL)
	# remotes::install_github("cran/SPARQL") this is archived by cran grrrr
	require(mapview)
	require(dplyr)
	library(stringi)

	# start gage
	gage_uri <- "https://geoconnex.us/ref/gages/1118104"

	{
	"@context": [{
	"schema": "http://schema.org/",
	"skos": "https://www.w3.org/TR/skos-reference/",
	"sosa": "http://www.w3.org/ns/sosa/",
	"hyf": "https://www.opengis.net/def/schema/hy_features/hyf/",
	"gsp": "http://www.opengeospatial.org/standards/geosparql/",
	"name": "schema:name",
	"sameAs": "schema:sameAs",
	"related": "skos:related",