February 2019
Beginner to intermediate
284 pages
6h 20m
English
Content preview from Learn Chart.js
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Displaying a map
Without any charting library, using just standard JavaScript, you can load a JSON file and draw a world map using Canvas. The data is a special JSON format that stores geographical shapes: GeoJSON. Its general structure is as follows:
{"type":"FeatureCollection", "features":[ {"type":"Feature",id":"AFG","properties":{"name":"Afghanistan"}, "geometry":{"type":"Polygon","coordinates":[[[61.210817,35.650072],...]] },{"type":"Feature", "id":"AGO", "properties":{"name":"Angola"}, "geometry":{"type":"MultiPolygon","coordinates":[[[[16.326528,-5.87747,...]] }, // many other lines ] }
Using JavaScript, you can load this file, parse it, and access each longitude and latitude pair. Then you can scale the values so that they fit into ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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