Struct QueryEngine 

pub struct QueryEngine { /* private fields */ }

QueryEngine is a structure that helps create queries to the Overpass API. It allows us to make lower level API calls (with the Overpass QL) as well as some higher level API calls such as just fetching a place of interest or a polygon of interest.

Implementations

impl QueryEngine

pub fn new() -> Self

Creates a new instance of the query engine with the base url set to:

https://overpass-api.de/api/interpreter

QueryEngine also has a default set of filters for ways. The filter is currently set to only fetch roads that can be driven on with a car. However, you might be interested in footpaths, railroads, etc. If you would like to change the filter, take a look at https://wiki.openstreetmap.org/wiki/Key:highway for more information on the options available.

Note that these filters are only applied when using higher level api calls such as Self::query_place. The lowest level api call, Self::query directly sends your query to the api without any modification.

pub fn url(&self) -> &str

Getter for the base URL that the QueryEngine uses.

pub fn with_url(&self, new_url: String) -> Self

Set a new url to query. Meant to be used in a functional style

use osmgraph::api::QueryEngine;

let engine = QueryEngine::new()
    .with_url("www.url_example.com".to_string());

pub fn filters(&self) -> &Vec<String>

Getter for the default way filters used in queries.

pub fn with_filters(&self, new_filters: Vec<String>) -> Self

Set new way filters in queries. Meant to be used in a functional style

use osmgraph::api::QueryEngine;

let engine = QueryEngine::new()
    .with_filters(vec![String::from("motorway")]);

pub async fn query_place( &self, area_name: String, admin_level: Option<usize>, ) -> Result<String, Error>

Given an area name, like “Manhattan” or “Germany”, and an admin level, return the nodes and ways for that specific area.

Admin level is a number that represents the scope of area you are interested in. In general: admin_level=2: Usually represents countries admin_level=4: Often represents states, provinces, or regions admin_level=6: May represent counties or districts admin_level=8: Often represents municipalities, cities, or towns admin_level=10: May represent neighborhoods or suburbs

If you don’t want to worry about admin levels, it is not required but will generally improve the results of your query.

pub fn query_place_blocking( &self, area_name: String, admin_level: Option<usize>, ) -> Result<String, Error>

This function does the same thing as Self::query_place but waits for the request to complete

pub async fn query_poly( &self, polygon: Vec<(f64, f64)>, ) -> Result<String, Error>

Given a closed polygon, return all of the nodes and ways within that polygon.

Note: the first and last element of the vector must be the same!

pub fn query_poly_blocking( &self, polygon: Vec<(f64, f64)>, ) -> Result<String, Error>

This function does the same thing as Self::query_poly but waits for the request to complete

pub async fn query(&self, query: String) -> Result<String, Error>

Requests data from the Overpass API given a particular query. The query must conform to the Overpass Query Language.

pub fn query_blocking(&self, query: String) -> Result<String, Error>

Behaves the same as Self::query, but will wait for the function to finish before continuing.

Trait Implementations

impl Clone for QueryEngine

fn clone(&self) -> QueryEngine

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for QueryEngine

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for QueryEngine

fn default() -> QueryEngine

Returns the “default value” for a type.