August 2017
Intermediate to advanced
500 pages
12h 3m
Japanese
Content preview from PythonとJavaScriptではじめるデータビジュアライゼーション
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400
18 章 D3 を使った地図の作成
を調べてみましょう。
18.3.3
経緯度線
地理形状ジェネレータの
1
つの
graticule
は、
d3.geo
の便利なコンポーネントで、ノーベル賞
の地図でも使います。
graticule
は、経線（経度の線）と緯線（緯度の線）の地球規模のメッシュ
をデフォルトで
10
度間隔で作成します。
path
をこの
graticule
に適用すると、図
18-1
に示した
ような適切に投影したグリッドを作成します。
例
18-4
は、地図に
graticule
を追加する方法を示しています。グリッドを地図パスの上に重ね
たい場合は、
DOM
ツリーで
SVG
パスが地図パスの後に現れるようにします。いずれわかるよう
に、
D3
の
insert
メソッドを使うとこの順序で行うことができます。
例
18-4
経緯度線の作成
var graticule = d3.geo.graticule()
.step([20, 20]); #
❶
svg.append("path")
.datum(graticule) #
❷
.attr("class", "graticule")
.attr("d", path); #
❸
❶
graticule
を作成し、デフォルトの
10
度間隔をオーバーライドする。
❷
datum
は
data([graticule])
の省略表現。
❸
path
ジェネレータを使って
graticule
データを受け取り、グリッドパスを返す。
グリッドオーバーレイと必要な
projection
を使って地図ファイルを
SVG
パスに変換する機能 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
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.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.