CODEWITHSUNDEEP
jsond3.js
pcproff
pcproff

Reputation: 622

JSON and changing datasets

I am fairly new to JSON and I want to create a choropleth example as so. http://gabrielflor.it/a-half-decade-of-rising-poverty Whenever the years are clicked it just goes to a different portion of the JSON (I'm assuming). Is this how functionality like this is usually done to avoid redrawing the whole map again and calling another JSON.js file? If so these .JSON files can get quite large?

Upvotes: 1

Views: 652

Answers (2)

phemios
phemios

Reputation: 674

Using a JSON is only a way to store values you need for each year. When you switch to another year the JS parse the JSON for the giving year and update the choropleth. For the example you have provided, here is the JSON used:

http://gabrielflor.it/static/data/saipe.json

This is a good way since you only have one JSON with every year you need and you load it only once. However since d3 needs datas this way I think you should add another JSON if you want to provide additional data like in gabrielflor example:

http://gabrielflor.it/static/js/d3.poverty-by-county.js?v=121107

He loads JSON like this with d3:

d3.json('../static/data/states.json', function (json) { states = json; });

or

d3.json('../static/data/saipehighlights.json', function (json) { saipehighlights = json; });

Upvotes: 1

Rafael Emshoff
Rafael Emshoff

Reputation: 2729

If you look at the network traffic for the example page you gave (ex. by using Chrome Developer Tools). The file with the poverty data is quite large, but the mapping data file is even larger. You'll notice, that it takes longer for the website to load, but afterwords it runs very smoothly in the client without making any server calls.

The site is just about browsing information and nice design - for that purpose I think a longer load time is quite acceptable if the user experience after is smoother(i.e. user doesn't have to wait for year data to load).

Upvotes: 0

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