Why Maps?

Maps help you organize, view and analyze data.

Examples

What are web maps?

Web Maps

Maps that are built for use on the web using tools that support web technology

Web maps are fast, flexible and dynamic

Web maps are connected to the information represented on the map

We know web maps are different than print maps

Web maps are still maps so the overarching requirement is that they are created with the purpose and user in mind

We still ask some of the same questions:

• What size will the map be?
• What geographic extent will the map be?
• What will the map scale be?
• What will the map projection be?

And some additional ones:

• Will other information be placed on top of the map?
• Will the map be viewed on multiple devices?
• Will the map be queried for additional information?

Some familiar examples...

MapQuest

Google Maps

Bing Maps

All these maps have common elements:

• A map
• A user interface
• Functionality to interact with the map

Let's travel back in time...

In 1996, MapQuest introduced the first popular web map

It was like a road map and yellow pages combined. Its primary purpose was to find places and get directions.

In 2005, Google released their version of the web map

Google Maps became more popular than MapQuest because the maps were faster

The maps were faster because of Google's use of map tiles

And Google also made its technologies available to developers through an API

Map Tiles

Pre-rendered images (tiles) that fit seamlessly together in geographic space in order to make maps load quickly.

Map tiles are 256x256 pixels and organized based on coordinates (x,y) and zoom levels (z).

Web Mercator

The tiling scheme used by most web maps.

Zoom Level

Defines the scale of the current map view. Ranges from 0 (entire world) to 21 (individual building level).

Map tiles and Web Mercator are still the de facto web mapping standard

That covers the "Map" portion of our web map, right?

Not yet.

Basemap vs. Overlay

Basemap

A map that provides geographic context to help support a wide variety of overlays - typically raster tiles.

Overlays

Themes of information overlaid on a basemap that help tell a story - typically vector.

More about the "Map"... we now have vector tiles

Vector Tiles

Similar to image tiles in terms of z/x/y but instead of images being served in each tile, data are.

User Interface

The "container" surrounding the map - built using HTML.

Map Functionality

Tools used to interact with the map and the overlaid content - added using JavaScript.

Map Tools

There are a number of tools that make it easier you and others to make web maps

Data Collection

@fulcrumapp

https//fulcrumapp.com

Collecting Data

* Webhooks

* Lookup Tables

* Complicated Relationships

* Integration

https//fulcrumapp.com

Data Collection

@fulcrumapp

https//fulcrumapp.com

OpenStreetMap

An openly licensed map of the world being created by volunteers using local knowledge, GPS tracks and donated sources.

© OpenStreetMap

Why choose OpenStreetMap?

Source:http://openstreetmap.us/2013/04/openstreetmap-in-government

Why we choose OpenStreetMap?

• A free worldwide dataset
• Updated frequently
• Takes advantage of local knowledge
• No technical or legal restrictions
• Easy to use

Editing Interface

OpenStreetMap Basic Elements

• Nodes (points)
• Ways (lines, polygons)
• Relations (two or more elements)
• Tags (keys and values)

Nodes

Ways

• Open Ways (i.e. Roads, Streams, Railway Lines)
• Closed Ways (i.e. Roundabouts, Circular Walkways)
• Areas (i.e. Landuse, Buildings, Parks)

Open Ways

Closed Ways

Areas

Relations

Tags

Use tags as key = value to define map features

Quantum GIS (QGIS)

A free and open source desktop geographic information system (GIS) that provides data viewing, editing, and analysis capabilities.

Top Plugins

CartoDB

Provider of a set of GIS and web mapping tools available in a cloud based platform.

Database in the Cloud

• Based on PostgreSQL with a geospatial extension called PostGIS
• Secure access

CartoDB Online Editor

• An online interface used to add/modify data, and create custom maps and visualizations
• Advanced option to manipulate data using SQL
• Advanced option to apply map styles using CartoCSS

Maps API

• A dynamic tile service that creates new tiles based on client-side requests

SQL API

• SQL statements can be used to retrieve data from the database
• Data are returned in multiple formats including JSON, GeoJSON, and CSV

CartoDB.js

• A JavaScript library built on top of Leaflet
• Wraps the Map and SQL APIs into visualizations or to integrate data into other web appications

CartoDB Demo

Mapbox

A provider of online maps and contributor to many popular online mapping libraries and applications.

Tools for custom map design

Mapbox Editor

Mapbox Editor

• An online mapping interface for basic map customization and data creation

Mapbox Studio

Mapbox Studio

• An open source tool used to design maps for the web using vector tiles
• Uses Mapnik for rendering and CartoCSS for styling

Mapbox.js

• A JavaScript library built on top of Leaflet
• Used to wrap Mapbox based maps and other functionality into web applications

iOS and Android SDK

• Tools used to build native mobile applications for iOS or Android

Mapbox API

• Used to power functions in maps like geocoding, routing, and offline caching

Leaflet

A modern open-source JavaScript library for mobile-friendly interactive maps.

Overview

• Has all of the features that most developers need to create web maps
• Works seamlessly across all major desktop and mobile platforms
• Designed with performance and usability in mind

History

• Created as an alternative to larger mapping libraries like Goggle Maps and OpenLayers
• Originally funded as a tool to be used with OpenStreetMap
• Mapbox is currently funding the majority of development, and has hired its creator

Users

• NPMap.js
• data.gov
• OpenStreetMap
• Many online map tools…

Create a basic Leaflet map

Create a basic HTML Container

<!DOCTYPE html>
                <html>
                <head>
                <title>
                  Leaflet Demo
                </title>
                </head>
                <body>
                </body>
                </html>
              

Create a basic Leaflet map

Include the Leaflet library CSS

  <head>
            <title>
            Leaflet Demo
            </title>
            <link rel=
            "stylesheet" 
            href="//cdn.leafletjs.com/leaflet-0.7.3/leaflet.css"
            />
            </head>
            

Create a basic Leaflet map

Include the Leaflet library JavaScript

  <body>
            <script src="//cdn.leafletjs.com/leaflet-0.7.3/leaflet.js"></script>
            </body>
            

Create a basic Leaflet map

Create a "div" for the map

  <body>
            <div id="map"></div>
            <script src="//cdn.leafletjs.com/leaflet-0.7.3/leaflet.js"></script>
            </body>
            

Create a basic Leaflet map

Style the "div"

  <head>
        <title>
        Leaflet Demo
        </title>
        <style>
            body,
            html {
            height: 100%;
            }
            #map {
            width: 100%;
            height: 100%;
            }
            </style>
            </head>
            

Create a basic Leaflet map

Create a script tag

  <body>
              <div id="map"></div>
              <script src="//cdn.leafletjs.com/leaflet-0.7.3/leaflet.js"></script>
              <script>
              </script>
              </body>
            

Create a basic Leaflet map

Create a map and assign it to the "div" element

var map = L.map('map').setView([39.75, -105], 15);
              

Create a basic Leaflet map

Create a tileLayer and assign it to the map

L.tileLayer('https://{s}.tiles.mapbox.com/v3/{id}/{z}/{x}/{y}.png', {
              maxZoom: 18,
              attribution: "OpenStreetMap, Mapbox, and NPS",
              id: 'nps.k7chg4fe'
              }).addTo(map);
            

Create a basic Leaflet map

Add a marker to the map

var marker = L.marker([39.75, -105]).addTo(map);
              

Modify the simple map to use GeoJSON

Add the "reqwest" library

  
              <body>
              <div id="map"></div>
              <style src="//cdn.leafletjs.com/leaflet-0.7.3/leaflet.js"></script>
              <style src="//cdnjs.cloudflare.com/ajax/libs/reqwest/1.1.5/reqwest.min.js"
              ></script>
              <script>
              ...
              </script>
              </body>
            

Modify the simple map to use GeoJSON

Load the GeoJSON from CartoDB

var geojsonLink = 'https://npmap-demo-account.cartodb.com/api/v1/sql?q=select+*+from+restaurants_modified&format=geojson';
            

Modify the simple map to use GeoJSON

Add the GeoJSON to the map

reqwest(geojsonLink, function(result) {
              L.geoJson(result).addTo(map);
              });
            

Style the data

Add a custom marker

reqwest(geojsonLink, function(result) {
            L.geoJson(result, {
            pointToLayer: function(feature, latlng) 
            {
            return L.circleMarker(latlng);
            }
            }).addTo(map);
            });
            

Style the data

Style the marker

reqwest(geojsonLink, function(result) {
            L.geoJson(result, {
            pointToLayer: function(feature, latlng) {
            return L.circleMarker(latlng, {
            color: 'white',
            fillOpacity: 1,
            radius: 6
            });
            }
            }).addTo(map);
            });
            

Style the data

Define the colors

var colors = {
            'Bar': '#8e44ad',
            'Cafe': '#e74c3c',
            'Pub ': '#16a085',
            'Restaurant': '#f1c40f'
            };
            

Style the data

Link the colors

reqwest(geojsonLink, function(result) {
            L.geoJson(result, {
            pointToLayer: function(feature, latlng) {
            return L.circleMarker(latlng, {
            color: 'white',
            fillColor: colors[feature.properties.amenity],
            fillOpacity: 1,
            radius: 6
            });
            }
            }).addTo(map);
            });
            

Add popups

Include Handlebars

  <body>
            <div id="map"></div>
            <script src="//cdn.leafletjs.com/leaflet-0.7.3/leaflet.js"></script>
            <script src="//cdnjs.cloudflare.com/ajax/libs/reqwest/1.1.5/reqwest.min.js"></script>
            <script src="//cdnjs.cloudflare.com/ajax/libs/handlebars.js/2.0.0/handlebars.min.js"></script>
            <script>
            ...
            </script>
            </body>
            

Add popups

Create a function to generate the popup content

var 
              popupContent
              =  
              function
              (
              properties
              ) {
              var content = '<div class="popup">' +
              '<span class="title">{{name}}</span><br/>' +
              '{{address}}<br/>' +
              '<hr/>' +
              '<span class="title">Amenity</span>: {{amenity}}<br/>' +
              '<span class="title">Cuisine</span>: {{cuisine}}<br/>' +
              '<span class="title">Rating</span>: {{rating}}' +
              '</div>';
              return Handlebars
              .compile(content)(properties);
              };
              

Add popups

Add an "onEachFeature" section

reqwest(geojsonLink, function(result) {
              L.
              geoJson(result, {
              pointToLayer: function(feature, latlng) 
              {
              return L.circleMarker(latlng, 
              {
              color: 
              'white'
              ,
              fillColor:
              colors[feature
              .properties
              .
              amenity],
              fillOpacity: 1,
              radius: 6
              });},
              onEachFeature: function
              (feature, layer)   
              {
              return layer
              .bindPopup(
              popupContent(feature    
              .
              properties));
              }
              }).addTo(map);
              });
              

Plugins

Leaflet plugins

http://leafletjs.com/plugins.html

leaflet.draw

Add CSS link

  
            <head>
            <title>
            Leaflet Demo
            </title>
            <link rel=
            "stylesheet" href=
            "//cdn.leafletjs.com/leaflet-0.7.3/leaflet.css" 
            />
            <link 
            rel="stylesheet" 
            href=
            "//leaflet.github.io/Leaflet.draw/leaflet.draw.js"
            />
            </head>
            

leaflet.draw

Add JavaScript link

  <body>
            <div id="map"></div>
            <script src="//cdn.leafletjs.com/leaflet-0.7.3/leaflet.js"></script>
            <script src="//cdnjs.cloudflare.com/ajax/libs/reqwest/1.1.5/reqwest.min.js"></script>
            <script src="//cdnjs.cloudflare.com/ajax/libs/handlebars.js/2.0.0/handlebars.min.js"></script>
            <script src="//leaflet.github.io/Leaflet.draw/leaflet.draw.js"></script>
            <script>
            ...
            </script>
            </body>
              

leaflet.draw

Sample Code

var drawnItems = new L.FeatureGroup();
            map.addLayer(drawnItems);
            var drawControl = new L.Control.Draw({
            draw: {
            position: 'topleft'
            ,
            polygon: {
          title:#{i+1}) #{element.label}

Planning a Web Map

Start with an open mind

Technology decisions come later

Basic steps:

Rules of thumb:

• Default to simple
• Avoid plugins at all cost
• Don't be afraid to create a snapshot of data
• Choose technologies based on requirements
• Eliminate complex technologies