Data, Maps, Usability, and Performance
It has been a while since I released the D3 Map Starter Kit and a lot has changed. The 4.0 version of D3 is modular, decentralized, and split into small libraries that you can use independently. It has changed some of the APIs so I have updated the World Map Template to work with D3 version 4, but how do we build a map with just the D3.js micro-libraries?
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After building a bunch of D3 map demos, I wanted to combine them all into a Map building tool, a Map Creator based on GeoJSON or TopoJSON with many design features, editing capabilities, and proper export to SVG or PNG. It started out as an enhancement to this GeoJSON and TopoJSON Visualizer and D3 Map Starter Template. I wanted to finally use dat.GUI as a visual controller for map creation. I added some preselected maps of the world, individual countries, and even states as well as the ability to add your own map data. You can change the map projection, resize the map container, and control various design elements from colors, opacity, stroke, and even textures via Textures.js.
You also have some powerful editing capabilities: ability to remove individual objects from the map and ability to merge objects together. The best thing is that you can edit the shape of any object by clicking on it and and zooming in. This exposes small green circles on object borders that can be dragged around and the drag event changes the object shape by automatically editing the SVG path data. My previous examples on working with SVG graphics helped in adding this feature. The final image can be saved as SVG or PNG using code from the Save SVG as PNG article. Finally, I integrated SimpleModal which has a textarea where you can add points (latitude, longitude, and location name) that get added as markers on the map.
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I have seen a lot of cool D3 maps of US states, counties, and even zipcodes but what about cities or towns? I don’t mean plotting geo coordinates of a particular city but actually drawing the city or town boundary on the map. A population choropleth is a good use case for this but I have only seen one example of Vermont that shows town specific information. The initial problem is where do we even get the specific town boundary geospatial data?
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I have taken another look at my responsive D3 map and had some time today to fix a few issues and make some enhancements. Normally, I would have updated my last post with the changes, but I wanted to take some time to explain the individual upgrades. Previously, I really focused on creating a world map with D3 that can not only be responsive in terms of screen size but also make that responsiveness work with zoom and pan limits. I added country names and colors to the geo data and included a simple tooltip feature for each country. Now, I am expanding on that with many enhancements, cross-browser fixes, and more simplified code.
Check out the new D3 World Map Template
Here is the updated D3.js v4 World Map Template
If you are familiar with “slippy map” APIs like Google Maps or Leaflet, than you probably never consider map projections and stick to the default Mercator projection. But there are many other projections (transposing our 3D earth to a 2D object like a paper or computer screen) and D3 comes with a great geo projection plugin. Most D3 examples leverage Natural Earth vector data and I wanted to do the same but show continents on the map instead of countries. So, today, I will create a World Map of Continents with D3 and a map projection visualization that shows how continents change the way they look with different map projections.
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I have previously shared some frustrations with aggregating a good list of countries and capitals. The problem is that the word country is a bit arbitrary and used to represent everything from sovereign states, various dependencies, special sovereign lands, uninhabited islands, and other entities. Adding to this, we have self-declared sovereign states like Somaliland that are unrecognized by most organizations so it’s hard to tell how you want to define that and which capital city to use. Moreover, there are countries that claim the same capital city (Jerusalem), islands with rotating capitals (Tokelau), and large geographical areas with no capital (Antarctica). So, here is my take on aggregating a complete list of countries and capitals of the world.
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I really like maps and today I want to list some of the best JavaScript frameworks, plugins, and libraries for making maps. Over the last few months, I have written a bunch of articles and demos on some of these JS mapping libraries but creating this compilation has opened my eyes to many more map APIs, jQuery plugins, and mapping solutions that I have not previously seen. Some of these map tools can really reduce the amount of effort needed to produce interactive maps. Many of these tools allow you to implement all kinds of dynamic maps with just a few lines of code. Here is a list of the top 50 JavaScript libraries and tools for making maps:
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With the recent launch of the new Google Maps and my love for maps, I want to dedicate a post and create something with the version 3 of the Google Maps API. Street View is capturing more and more interesting locations around the world and it’s great that Google is constantly enhancing this feature. On top of this, other people are innovating and making things like Google Street Viewer and Hyperlapse which combine Google Street View and WebGL to make some awesome effects. The Google Maps API also supports 45° imagery for certain locations, which is another interesting map type. So, today, I will combine all these map views and create a Google Maps demo that explores geo locations with three different map types: roadmap, streetview, and tilt.
After creating my last D3 game, I wanted to follow up with a similar concept but focus more on country names and zooming animation. It’s basically a recreation of Mike Bostock’s World Tour but in a game format with some extra features, like zooming into a country, keeping score, and providing hints. Most of the code has been re-implemented from my other D3 demos and I have added capitals data directly into the TopoJSON. Let’s look at the code.
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Drag and Drop SVG Geography Game
I wanted to write a game for a while, so today I decided to create a geography game with D3.js. The idea is to let the player drag and drop territories into their appropriate place on the world map. The map is rendered using the Robinson projection and only the top 100 territories are chosen according to land area. These 100 “countries” are shuffled on each refresh and upon a successful drop, the land changes color to green. If the player makes a mistake, a hint is provided: all the countries that border the selected country. The player has one more try to drag the land into the right place or the land turns red, animates on its own to the right place, and the next territory is loaded. The goal is to get a perfect score and learn where every country is located on a map. Let’s look at the code.
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