72 lines
3.0 KiB
HTML
72 lines
3.0 KiB
HTML
<!DOCTYPE html>
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<html>
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<head>
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<title>Reading Features From CartoDB using GeoJSON</title>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link rel="stylesheet" href="../theme/default/style.css" type="text/css">
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<link rel="stylesheet" href="style.css" type="text/css">
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<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
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<meta name="apple-mobile-web-app-capable" content="yes">
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<script src="../lib/OpenLayers.js"></script>
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</head>
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<body>
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<h1 id="title">Reading Features From CartoDB using GeoJSON</h1>
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<div id="tags">
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protocol, script, cartodb
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</div>
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<p id="shortdesc">
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Demonstrates how to load features on OpenLayers using CartoDB SQL API.
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</p>
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<div id="map" class="smallmap"></div>
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<div id="docs">
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<p>
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<a href="http://cartodb.com/">CartoDB</a> is an Open Source
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Geopatial Database on the cloud. It allows you to import your
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data in shapefiles, KML, OpenStreeMap files, CSV, etc. and
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then analyze and visualize it. Internally CartoDB uses PostGIS
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2.0 so all functionality in PostGIS can be used straight
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away. CartoDB exposes two APIS. One
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to <a href="http://developers.cartodb.com/documentation/cartodb-apis.html#maps_api">generate maps</a>
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as tiles with interactivity, and another <a href="http://developers.cartodb.com/documentation/cartodb-apis.html#sql_api">SQL API</a>
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to retrieve vector data using among other formats, GeoJSON. In
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this example we do a very simple query to obtain all protected
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areas in Costa Rica from a public table. You can adapt the SQL
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to include where clauses or complicate geospatial queries.
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</p>
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<p>
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View the source code of this page to see how this is done. And
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check the table on CartoDB
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for <a href="https://examples.cartodb.com/tables/costa_rica_pa/public#/map">Protected Areas in Costa Rica</a>
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</p>
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</div>
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<script>
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var map = new OpenLayers.Map({
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div: "map",
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layers: [
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new OpenLayers.Layer.OSM(),
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new OpenLayers.Layer.Vector("Vectors", {
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projection: new OpenLayers.Projection("EPSG:4326"),
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strategies: [new OpenLayers.Strategy.Fixed()],
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protocol: new OpenLayers.Protocol.Script({
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url: "http://examples.cartodb.com/api/v2/sql",
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params: {
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q: "select * from costa_rica_pa LIMIT 50",
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format: "geojson"
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},
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format: new OpenLayers.Format.GeoJSON({
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ignoreExtraDims: true
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}),
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callbackKey: "callback"
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}),
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eventListeners: {
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"featuresadded": function() {
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this.map.zoomToExtent(this.getDataExtent());
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}
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}
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})
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]
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});
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</script>
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</body>
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</html>
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