[Pelias](https://mapzen.com/products/search/) is a modern, geographic search service based entirely on open-source tools and open data. Use this functionality to enhance any app that has a geographic context, such as ones that help in delivering goods, locating hotels or venues, or providing local weather forecasts.
Through a process known as [geocoding](https://en.wikipedia.org/wiki/Geocoding), Pelias allows you to enter an address or the name of a landmark or business, and the service translates the result into geographic coordinates for mapping. Pelias is built on [Pelias](pelias.io), an open-source geocoding project.
In this tutorial, you will learn how to make a map with a search box that allows you to enter addresses and place names and locate them on a map. To complete the tutorial, you should have some familiarity with HTML and JavaScript, although all the source code is provided. You can use any text editor and operating system, but must keep an Internet connection while you are working.
You also need a Mapzen API key, which you can get by following the steps in the Mapzen [developer overview](https://mapzen.com/documentation/overview/).
To get started making your map, you will need to use a text editor to update the HTML. See some of Mapzen's [suggested text editors](https://mapzen.com/documentation/guides/install-text-editor/) in the developer guide documentation.
1. Start your text editor with a blank document and copy and paste the following HTML. (Note: If the text editor you are using requires you to name and save a document at the time when it is first created, call the file `index.html`.)
These form the basic structure of an HTML document. `<!DOCTYPE html>` goes at the top of every HTML page and indicates that it is written for HTML5, and the `<html>` tags tell your browser that the content is HTML. The `<head>` tag contains the title for the page and other metadata about the page, while the `<body>` is where you add the code and the rest of the content on your page. There are many [web tutorials](http://www.w3schools.com/html/default.asp) available to help you experiment with and learn more about HTML documents and the tags in them.
A cascading style sheet (CSS) is used to style a webpage, including layout and fonts, and JavaScript adds functionality to the page. In your `index.html` file, you need to list the CSS and JavaScript files needed to build your page.
The [Leaflet JavaScript library](http://leafletjs.com/) provides tools for building an interactive map for web and mobile devices. Leaflet is extensible, and developers have built additional tools for Leaflet maps.
The [Mapzen.js library](https://www.mapzen.com/documentation/mapzen-js/) simplifies the process of using Mapzen's maps within Leaflet. Mapzen.js contains all the Leaflet functionality, as well as additional tools for working with Mapzen maps and search.
2. Save your edits and refresh the browser. The webpage should still appear empty because you have not added any code to interact with these references.
Note that you are linking to a website that is serving the Mapzen.js CSS and JavaScript, but you can also [view, download, and contribute to the source code](https://github.com/mapzen/mapzen.js) if you want to access the contents of the library.
To display a Leaflet map on a page, you need a `<div>` element, which is a container on the page that groups elements, with an ID value. If you want to know more about initializing a Leaflet map, see the [Leaflet getting started documentation](http://leafletjs.com/examples/quick-start.html).
1. At the bottom of the `<head>` section, after the references you added in the earlier steps, add a `<style>` tag and the following attributes to set the size of the map on your webpage. A Leaflet map will not display unless you include a width.
`L.xxxxx` is a convention used with the Leaflet API. The `center: [47.61033,-122.31801]` parameter sets the center point of the map, in decimal degrees, at the location of a building at Seattle University.
The next line sets the `zoom` level, which is like a map scale or resolution, where a smaller value shows a larger area in less detail, and a larger zoom level value depicts smaller area in great detail.
To recap how you created this, you added references to the Mapzen JS and CSS files, a map `<div>` with a declared width, and assigned the `map` value to `L.Mapzen.map`.
So far, you have referenced the necessary files, initialized Leaflet with a map container on the page, and added data to the map. Now, you are ready to add the Search box.
1. Inside the same `<script>` tag, and after the code you just added for the map, initialize a search box and add it to the map with the following code.
2. Save your edits and refresh the browser. You should see search button in the left corner. If you want to expand the button to a box, you can change this behavior in the geocoder options.
Now, you will test your search box by finding a few locations. As you type, the text automatically completes to suggest matching results.
1. On the map, type `Seattle University` in the Search box.
2. In the results list, find the entry for `Seattle University` and click it to zoom and add a point to the map at that location. (The point is only on your map, and does not update OpenStreetMap.)
3. Search for other addresses or places to experiment with the search function and get an idea of the results it returns. For example, you might try looking for a point of interest in Seattle, your work address, or a city outside the United States.
From a technical perspective, Pelias is a web service with that has various API endpoints that allow you to access web resources through a URL. Behind the scenes, the geocoder is constructing a URL with the parameters you specify and sending it to the Pelias web service. The service returns [human-readable JSON](https://en.wikipedia.org/wiki/JSON), short for JavaScript Object Notation.
Mapzen.js provides options for customizing the way you interact with the map, and Pelias is also very flexible. Now that you have a map on your page with a Search box, you can add more features to it. You need to modify the line defining the geocoder to include additional parameters.
Up to this point, you have been using the Pelias [\autocomplete](https://mapzen.com/documentation/search/autocomplete/) endpoint, which searches on text as you type it. In this section, you will switch to the [\search](https://mapzen.com/documentation/search/search/) endpoint to see how it behaves. The `autocomplete` functionality helps you find partial matches, whereas `search` prioritizes exact words because it assumes you have finished typing when you perform the query.
If you look at your browser's developer tools console as you are doing this, you can see the query URL changes from `https://search.mapzen.com/v1/autocomplete?text=` to `https://search.mapzen.com/v1/search?text=` to reflect the `search` endpoint.
Although you will not be using it in this tutorial, [\reverse](https://mapzen.com/documentation/search/reverse/) is another common Pelias endpoint. It performs reverse geocoding to find the address at a given coordinate location. You can find a listing of all the endpoints and parameters in the [Pelias documentation](https://mapzen.com/documentation/search/).
You are setting `autocomplete: false` to specify that the Search box should not suggest potential text matches as you type. Autocomplete is enabled by default, so adding this means that you will turn it off.
1. Open your browser's developer tools console. In Chrome, you can do this by clicking the menu in the corner, pointing to More Tools, and clicking Developer Tools.
2. Click the Network tab to see the Internet traffic, including the queries to the Mapzen servers.
3. Click the Headers tab for more information about the request, including the full URL. For example, the URL might look something like `https://search.mapzen.com/v1/search?text=901%2012th%20avenue&focus.point.lat=47.61032944737081&focus.point.lon=-122.31800079345703&api_key=your-mapzen-api-key`
4. Paste this URL into a new browser tab and use your own API key to see the JSON response, which can be mapped.
_Tip: You can install a plug-in for your browser to display JSON in a more formatted manner. You can search the web store for your browser to find and install applicable products._
Pelias uses a [variety of open data sources](https://mapzen.com/documentation/search/data-sources/), including OpenStreetMap. Part of the power of open data is that anyone can change the source data and improve the quality for everyone. If you are unable to find a location, the place could be missing or incorrect in the source datasets.
You can choose which data sources to search by passing a parameter for the `sources`. In addition, you need to enclose with single quotation marks any parameter names that use the dot notation (such as `boundary.country`) to make sure JavaScript can parse the text correctly.
As you were searching, you might have noticed results that looked similar. Pelias does perform some elimination, but the differing data sources may still cause seemingly matching results to appear. Choosing a particular data source can reduce the occurrence of duplicated entries.
1. Within the `geocoderOptions` block, add the `params:` list and a parameter for `sources:`. Be sure to add a `,` at the end of the `autocomplete: false` line.
Pelias provides options for customizing your search parameters, such as limiting the search to the map's extent or prioritizing results near the current view. Right now, you may notice that results from around the world appear in the list.
Mapzen.js automatically provides a [focus point](https://mapzen.com/documentation/search/search/#prioritize-around-a-point) for you based on the current map view extent. You can add other parameters to filter the search results, such as to limit the results to a particular country or type of result.
1. Within the `geocoderOptions` block, add add a `,` at the end of the `sources: 'osm'` line and then a parameter for `'boundary.country': 'USA'` on the next line. You need to enclose with single quotation marks any parameter names that use the dot notation (such as `boundary.country`) to make sure JavaScript can parse the text correctly.
4. Search again for city names in the Search box. Notice that you only see results from within the United States. For example, `Vancouver` in Canada is no longer listed, but you can find the city in Washington.
5. Optionally, trying changing the `boundary.country` to another country code, such as `AUS` for Australia. There is a [specific format](https://en.wikipedia.org/wiki/ISO_3166-1) you need to use for the country code. Change the code back to `USA` when you are done.
In Pelias, types of places are referred to as `layers`, and you can use these to filter your results. For example, if your app has an input form where your users should only be able to enter a city, you can use Pelias to limit the results to show only matching city names. This is common in travel apps, such as searching for a hotel or flight, where you enter a destination city.
You can review the [Pelias documentation](https://mapzen.com/documentation/search/search/#filter-by-data-type) to learn the types of `layers` you can use in a search.
1. Within the `geocoderOptions` block, add add a `,` at the end of the `'boundary.country: 'USA'` line and then a parameter for `layers: 'address,venue'` on the next line.
3. Search for `102 Pike Street, Seattle, WA 98101` (the first Starbucks) and press Enter. Some other places you can try include `Starbucks`, `400 Broad Street` (the address of the Space Needle), `Space Needle`, and `University of Washington`.
In this tutorial, you learned the basics of adding the Pelias geocoding engine to a map using [Mapzen.js](https://mapzen.com/documentation/mapzen-js/), and making some customizations to improve the search results.
Because the geocoder is still under development and considered experimental, if you are getting unexpected search results, please add an issue to the [Pelias GitHub repository](https://github.com/pelias/pelias/issues). The developers can investigate and decide if the problem is caused by software or data, and work to fix it either way.
