Question

我正在尝试使用地图API查找特定区域内的POI数量。我建议使用诺基亚或Yelp API，但我很难弄清楚如何开始这个项目。

兴趣点的实际类型并不重要，在这种情况下都是相关的。如果有人对这些地图API有任何经验，并且知道我应该看什么，或者对我有用的例子，我将非常感激！

由于

Answer 1

首先要看的是相关API的开发者文档站点。对于诺基亚API，您将看到JavaScript documentation或RESTful Places API，对于Yelp，请尝试http://www.yelp.com/developers/下的链接（免责声明 - 我个人不使用Yelp）

有许多例子使用API explorer内的诺基亚广场api进行播放，并在屏幕上查看结果。

以下是一些有用的例子，可以帮助您入门

Nokia Places API和Yelp API都是本地搜索API - 换句话说，他们总是回答“我在哪里可以找到X 接近 Y？”的问题，因此找到总计数据库中的POI数量不是一个现实的任务（因为许多POI将被视为与搜索位置无关，您可以做的是找到特定位置内POI的密度。

下面的代码最初将显示柏林市中心的书店，但如果您更改地图的焦点，它也会在其他城镇找到书店。您需要获得自己的免费app id and token才能使其正常运行。

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!-- 
    Example from Nokia Maps API Playground, for more information visit http://api.maps.nokia.com
 -->
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <meta http-equiv="X-UA-Compatible" content="IE=7; IE=EmulateIE9"/>
        <meta http-equiv="content-type" content="text/html; charset=UTF-8"/>
        <title>Nokia Maps API Example: Search by category</title>
        <meta name="description" content="Search by category"/>
        <meta name="keywords" content="search, services, places, category"/>
        <!-- For scaling content for mobile devices, setting the viewport to the width of the device-->
        <meta name=viewport content="width=device-width, height=device-height, initial-scale=1.0, maximum-scale=1.0, user-scalable=no"/>
        <!-- By default we add ?with=all to load every package available, it's better to change this parameter to your use case. Options ?with=maps|positioning|places|placesdata|directions|datarendering|all -->
        <script type="text/javascript" charset="UTF-8" src="http://api.maps.nokia.com/2.2.3/jsl.js?with=all"></script>
        <!-- JavaScript for example container (NoteContainer & Logger)  -->
        <style type="text/css">
            html {
                overflow:hidden;
            }

            body {
                margin: 0;
                padding: 0;
                overflow: hidden;
                width: 100%;
                height: 100%;
                position: absolute;
            }

            #mapContainer {
                width: 80%;
                height: 80%;
                left: 0;
                top: 0;
                position: absolute;
            }
            #progress {
                width: 80%;
                height: 10%;
                left: 0;
                top: 80%;
                position: absolute;
            }
            #buttons {
                width: 80%;
                height: 10%;
                left: 0;
                top: 90%;
                position: absolute;
            }
        </style>
    </head>
    <body>
        <div id="mapContainer"></div>
        <div id="progress"></div>
        <div id="buttons">
         <a onClick="searchByCategory( map.center, 'bookshop' );return false;" href="#">Find Bookshops</a> 
        </div>
        <script type="text/javascript" id="exampleJsSource">
/*  Set authentication token and appid 
*   WARNING: this is a demo-only key
*   please register on http://api.developer.nokia.com/ 
*   and obtain your own developer's API key 
*/
nokia.Settings.set("appId", "YOUR APP_ID"); 
nokia.Settings.set("authenticationToken", "YOUR TOKEN");


// Get the DOM node to which we will append the map
var mapContainer = document.getElementById("mapContainer");
// Create a map inside the map container DOM node
var map = new nokia.maps.map.Display(mapContainer, {
    // Initial center and zoom level of the map
    center: [52.51, 13.4],
    zoomLevel: 10,
    components: [       
        new nokia.maps.map.component.Behavior()
    ]
});

var searchManager = nokia.places.search.manager,
    resultSet;


var searchCat;  
var maxDistance = 0;

// Function for receiving search results from places search and process them
var processResults = function (data, requestStatus, requestId) {
    var i, len, locations, marker;



    if (requestStatus == "OK") {
        // The function findPlaces() and reverseGeoCode() of  return results in slightly different formats
        locations = data.results ? data.results.items : [data.location];
        // We check that at least one location has been found
        if (locations.length > 0) {
            // Remove results from previous search from the map
            if (resultSet) map.objects.remove(resultSet);
            // Convert all found locations into a set of markers
            resultSet = new nokia.maps.map.Container();
            for (i = 0, len = locations.length; i < len; i++) {
                marker = new nokia.maps.map.StandardMarker(locations[i].position, { text: i+1 });
                resultSet.objects.add(marker);
                if (locations[i].distance > maxDistance){
                    maxDistance = locations[i].distance;
                }
            }
            // Next we add the marker(s) to the map's object collection so they will be rendered onto the map
            map.objects.add(resultSet);
            // We zoom the map to a view that encapsulates all the markers into map's viewport
            map.zoomTo(resultSet.getBoundingBox(), false);


            progressUiElt.innerHTML = locations.length  + " places found in the '" + searchCat + "' category within " + maxDistance + "m of "+ data.search.location.address.city ;
        } else { 
            alert("Your search produced no results!");
        }
    } else {
        alert("The search request failed");
    }
};



// Binding of DOM elements to several variables so we can install event handlers.
var progressUiElt = document.getElementById("progress");


searchByCategory = function(searchCenter   , category){
// Make a place search request
searchCat = category;
progressUiElt.innerHTML = "Looking for places in the '" + category + "' category...'";
searchManager.findPlacesByCategory({
    category: category,
    onComplete: processResults,
    searchCenter: searchCenter,
    limit: 100,
});
}
// Search for Bookshops in Berlin
searchByCategory( new nokia.maps.geo.Coordinate(52.51, 13.4), "bookshop" );

        </script>
    </body>
</html>

所以你可以看到柏林有超过100家书店，但波茨坦只有37家。

使用Nokia / Yelp Map API查找区域中的POI

1 个答案: