Roger Veciana i Rovira rveciana

The introduction to Reactive Programming you've been missing

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

A demonstration of how to calculate the areas of Voronoi regions clipped by geographic features using D3.

[D3’s implementation](Sutherland–Hodgman algorithm) of the Sutherland–Hodgman algorithm only works for convex clip polygons, but we exploit the fact that Voronoi regions are guaranteed to be convex, and use each Voronoi region as a clip polygon, with the projected geographic boundary as a subject polygon.

In response to a question by Gonzalo Bellver.

Object selection is tough, particularly when the things you'd like to select are moving around (like nodes in a force-directed layout, perhaps). Allowing a user the fudge factor of an area cursor helps, but can get in the way when targets are small enough. The use of a Voronoi tessellation promises a map of closest node for any given point.

This example illustrates the use of a Voronoi overlay to clip nodes in a force-directed simulation. By using the Voronoi shapes as the clipping path the nodes themselves can be drawn much simpler.

This builds on these two examples from Mike Bostock on force-directed graphs and voronoi tesselation, as well as Nate Vack's Voronoi selection example here and this first pass at an integration from Christopher Manning.

Created by Christopher Manning

Summary

This is a map of the Chicago Wards that demonstrates how to use the JSTS Topology Suite and D3.js to find and display intersections between polygons.

Wards shaded grey are scanned since their bounding boxes intersect with the search envelope and wards shaded blue intersect with the search

This is companion code to this guide.

	var blob = window.atob("AAAAAAAAAAAAAAAAAACAPwAAAAAAAAAAAAAAAAAAgD8AAAAA"), // Base64 string converted to a char array
	fLen = blob.length / Float32Array.BYTES_PER_ELEMENT, // How many floats can be made, but be even
	dView = new DataView( new ArrayBuffer(Float32Array.BYTES_PER_ELEMENT) ), // ArrayBuffer/DataView to convert 4 bytes into 1 float.
	fAry = new Float32Array(fLen), // Final Output at the correct size
	p = 0; // Position

	for(var j=0; j < fLen; j++){
	p = j * 4;
	dView.setUint8(0,blob.charCodeAt(p));
	dView.setUint8(1,blob.charCodeAt(p+1));

	!!
	!! Implementation of JSONPatch (http://jsonpatch.com/) using PostgreSQL >= 9.5
	!!

	CREATE OR REPLACE FUNCTION jsonb_copy(JSONB, TEXT[], TEXT[]) RETURNS JSONB AS $$
	DECLARE
	retval ALIAS FOR $1;
	src_path ALIAS FOR $2;
	dst_path ALIAS FOR $3;
	tmp_value JSONB;

	/*
	UPDATE July 2016 , moved and updated to here: https://github.com/Sumbera/gLayers.Leaflet

	Generic Canvas Overlay for leaflet,
	Stanislav Sumbera, April , 2014

	- added userDrawFunc that is called when Canvas need to be redrawn
	- added few useful params fro userDrawFunc callback
	- fixed resize map bug
	inspired & portions taken from : https://github.com/Leaflet/Leaflet.heat

	{% assign array = 'c\|c\|b\|b\|a\|a' \| split: '\|' %}
	{% assign tags = array[1] %}

	{% for item in array %}
	{% unless tags contains item %}
	{% capture tags %}{{ tags }}\|{{ item }}{% endcapture %}
	{% endunless %}
	{% endfor %}

	{{ tags \| split: '\|' \| sort \| join: ', ' }}