Maps on the Web!

Presentatie en workshop voor Provincie Zuid-Holland

Door: Niene Boeijen

Deze presentatie en workshop materialen:

Wie ben ik?

Web Cartograaf & Geo ICT developer

Event Organizer: Maptime Amsterdam & Utrecht

Stage Geo Web Visualization[1]
[2] [3]

Msc Geo Information Science & Remote Sensing [1]

We make interactive maps and visualizations.

TOP team

Waarom deze workshop?

Wat gaan we doen vandaag?

  • Geo data
  • Projecties en coördinaat systemen!?
  • Geo data naar het Web
    • Tiles
    • WMS en WFS
  • Tools en technieken
  • Hands on! Workshop zelf een web map maken met Leaflet.js of ArcGIS JavaScript API
  • Afsluiting met Web Frameworks en toekomst web van web maps

Doel workshop

Aan het einde van deze workshop heb je je eigen werkende web pagina met een interactieve kaart. De kaart bevat de officiële Nederlandse achtergrondkaart van PDOK én een WMS laag van GIS afdeling. Dit allemaal in de Nederlandse RijksDriekhoekstelsel projectie.


Je hebt geen uitgebreide voorkennis nodig van JavaScript, HTML, CSS, Leaflet.js, de ArcGIS JavaScript API of WMS en WFS servers. Deze workshop helpt je met de eerste kennismaking hiervan.

Laten we beginnen!

Het Web Map Universum!

GeoData van Desktop naar het Web

Doel >> Functionaliteit >> Mapping Technologie >> Design


Veel manieren om geo-data op het web te krijgen!

  • Interactieve/statische web map
  • Web GIS applicatie
  • Download link
  • Animated, real time
  • Collaborative web maps
  • Online atlasses
  • Infographic, plaatje, video, gif
  • Hoeveelheid data
  • Benodigde interactie
  • apparaat
  • Online/offline

Geo Data = Data + Location

Vector vs Raster

Maps = Collection of Geo data

Maps organize complex data about the environment.

Reveal patterns and relationships.

Maps allow us to communicate about location using a common framework

Coordinate system

Communicate locations & distances on the Earth's surface

Shape of the earth?

The real shape of the earth is too complex to be useful as a reference for measurement..

Geographic coordinate system

3D model

Longitude Latitude

Projected coordinate system

Mathematical projection / translation


Geographic Coordinate System:

WGS84 EPSG:4326

Lon Lat in decimal degrees


Standard way to store most geodata for the Web:


                "type": "Feature",
                "geometry": {
                    "type": "Point",
                    "coordinates": [5.2394137,52.0819662]
                "properties": {
                    "name": "Hotel Theater Figi"

Projected Coordinate System:

Spherical/Web Mercator EPSG:3857

Square, scale not relevant, shapes important

We store data in EPSG:4326, but display it in EPSG:3857!

Why is Mercator wrong?

Web maps en Projecties

True Size puzzle

West Wing

Projected Coordinate System:

RD New EPSG:28992


Geographic Coordinate System:

WGS84 EPSG:4326

Projected Coordinate System:

Web Mercator EPSG:3857

Projected Coordinate System:

RD New EPSG:28992



  1. Tegel cache

  2. Serveren

What is a web map?

Analogue paper maps

Digital maps VS Web Maps
Data Tiles, styles and servers
On the computer View in a browser
Calculate, analyze scroll, pan, zoom

a little History

Digital maps

GIS software

GIS on the Web is not user friendly..

1996 Mapquest first with a web service!

But really slow to load..

in 2004 Endoxon found a way for quick online mapping!

2005 Google Maps took over!

The solution?



All tiles size 256x256 pixels

Placed in a grid, sharing boundaries

Seamless map

All these little tiles load way faster than one big map!

We call this slippy maps

Zoom levels

Each zoom level has its own set of tiles!

Zoom level 0: 1 tile for the whole world.

Increases exponentially...

Zoom level 1: 4 tiles

Zoom level 2: 16 tiles


Map with tile bounds

Styling & Serving tiles

Tiles are styled and rendered in advance

Tiles are just images on the web


Serving data

Open Geospatial Consortium

The Open Geospatial Consortium (OGC) is an international not for profit organization committed to making quality open standards for the global geospatial community

WMS Web Map Service

WFS Web Feature Service


Map Server op een GeoDatabase







XML > GML Geography Markup Language


Map Layers vs Data Layers!

Base Layer


Data Layer / Feature Layer



Web Map Building blocks

Data, styled, tiles, server:

Base Layer

Additional Data:

Vector Layers

Interface and Interaction

Zoom, panning, clicking etc.

Front-end libraries - JavaScript!

Puts it all together,

Tiles, content, interaction

Making a Web Page

New to HTML & CSS?

Start with Making a web page

Or use Code Academy

JavaScript Library

Including a JavaScript library in your code is like copying and pasting someone else's code into yours. You have access to everything in that library.

In our case, it's a bunch of cool tools to make web maps and give them familiar functionality.

JavaScript Libraries for Mapping




Google Maps



ArcGIS JavaScript API


An Open-Source JavaScript Library for Mobile-Friendly Interactive Maps

simplicity, performance and usability

What Leaflet does:

Quick simple web maps


Weighing about 38 KB of JS.

Has all the mapping features most developers ever need.

Can be extended with Plugins

Well documented

What Leaflet does not do:

Provide data for you.

Provide the basemap.

Its not GIS

Leaflet is a framework

ArcGIS JavaScript API

ESRI StoryMaps

R Shiny applicatie

Let's Map!

Everything is on Github


Used for code.

Version control.



Use a good text-editor

Nodepad ++

With Syntax Highlighting!

The workshop

follow the steps

Web Frameworks

Leaflet en ArcGIS JS zijn geen Frameworks maar libraries


Makkelijk om een hele applicatie te ontwikkelen

Dynamische websites

multiple page

content management

Set of libraries


Meest bekende van het moment:

Front end JavaScript Frameworks







Web Mapping en toekomst?
We no longer go to maps to find out where we are. Instead, we tell maps where we are and they form around us on the fly. [source]
There has never been more open data available than at this moment in time, and everyone from global NGOs to armchair hobbyists are using that data to create maps. [source]
Cartografie is geen niche meer:
  • Big data
  • Massaconsumptie
  • Open source sofware
  • Open data

Web Mapping

  • snelheid en schaalbaarheid
  • Data-gestuurd
  • Responsive ontwerp
  • Gepersonaliseerd

Cartography is the new code. [source]


You need to be able to find, manipulate, and store spatial and non-spatial data.
You need to be able to design a functional and attractive cartographic representation of that data as well as the UI controls to operate it.
You need to be able to implement that design through code.
[source: Axis Maps]

van Cartograaf naar ..

Data-analist / GIS-specialist

Full-stack ontwikkelaar

Interactie-ontwerper (IX)

User Experience-ontwerpter (UX)

Meer info en workshops?

My lists of

interesting links, workshops, presentations and background information:

for webmapping in general and d3 & Leaflet

about vector tiles

Check mijn github:


Niene Boeijen