Digital Geography

Make it simple – How to add Line Simplifcation to your Web Mapping

When Mike Bostock published his (re-) implementation and demonstration of Visvalingams algorithm for line simplification he attracted considerable attention on that. What is a little bit strange in my opinion. This algorithm is old hat as like the second more well-known algorithm invented by Douglas-Peucker. Both can be seen as the basic concepts for the simplification of linear geometric objects when a quick & easy implementable point reduction is essential. And this is what they can achieve…reducing the amount of points, by analysing the topology of each point…not more but also not less! They are well-known and (relativ) easy implementable…

D3 Geodata Basics – A Map Overlay can have many Faces

Within that tutorial I will show you how to: add a geoJSON file using pure Leaflet open a geoJSON file with D3 open a TopoJSON file with D3 add a map-overlay to a leaflet map using D3 Again…we begin with a simple map … already seen in D3 mapping basics and in geoJSON & Leaflet Add a geoJSON file using pure Leaflet You should know how to do this! Just add some very simple data to the map, as we have already done it in a previous post! Import the data file… …add the data to the map… …define the…

D3 Mapping Basics

Within this, 2nd basic D3 tutorial, I will show you how to combine D3 with Leaflet whereby each library can demonstrate its vantages! These will be the main topics: Set up a map using Leaflet Add an individual zoombar Show the center of the map Show the extent of the map Get a 1st impression of d3.scale() When you are not familiar with D3 or Leaflet I recommend you to apply these tutorials, previously: D3 Basics geoJSON & Leaflet Set up a map using Leaflet Let’s begin by setting up an html-file containing a very simple map. How this can…

D3-Basics – All you need is a selection!

Since a while I am programming with the JavaScript library D3.js … and … I am addicted to it! As I would like to present some tutorials on D3’s fantastic possibilities to create and design webmapping solutions … I think it would be good to give you a description on the things that I would identify as elementary. Caution! This tutorial could be a little bit too detailled for you, when you are a skilled JavaScript programmer! I am sorry for that! But when you are a noob in JavaScript, as I was when I began to program with D3,…