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D3.js地图打点射线动效
在项目中，通常使用打点和射线来实现区域的攻防、传达、运动等需求，
最终效果
代码解析
首先引入d3V3和snap
导入地图数据
{"type":"FeatureCollection",
"bbox": [ -180.0, -89.99893, 180.0, 83.59961 ],
"features":[
{"type":"Feature","properties":{"name":"Afghanistan"},"geometry":{"type":"Polygon","coordinates":[[[61.210817,35.650072],[62.230651,35.270664],[62.984662,35.404041],[63.193538,35.857166],[63.982896,36.007957],[64.546479,36.312073],[64.746105,37.111818],[65.588948,37.305217],[65.745631,37.661164],[66.217385,37.39379],[66.518607,37.362784],[67.075782,37.356144],[67.83,37.144994],[68.135562,37.023115],[68.859446,37.344336],[69.196273,37.151144],[69.518785,37.608997],[70.116578,37.588223],[70.270574,37.735165],[70.376304,38.138396],[70.806821,38.486282],[71.348131,38.258905],[71.239404,37.953265],[71.541918,37.905774],[71.448693,37.065645],[71.844638,36.738171],[72.193041,36.948288],[72.63689,37.047558],[73.260056,37.495257],[73.948696,37.421566],[74.980002,37.41999],[75.158028,37.133031],[74.575893,37.020841],[74.067552,36.836176],[72.920025,36.720007],[71.846292,36.509942],[71.262348,36.074388],[71.498768,35.650563],[71.613076,35.153203],[71.115019,34.733126],[71.156773,34.348911],[70.881803,33.988856],[69.930543,34.02012],[70.323594,33.358533],[69.687147,33.105499],[69.262522,32.501944],[69.317764,31.901412],[68.926677,31.620189],[68.556932,31.71331],[67.792689,31.58293],[67.683394,31.303154],[66.938891,31.304911],[66.381458,30.738899],[66.346473,29.887943],[65.046862,29.472181],[64.350419,29.560031],[64.148002,29.340819],[63.550261,29.468331],[62.549857,29.318572],[60.874248,29.829239],[61.781222,30.73585],[61.699314,31.379506],[60.941945,31.548075],[60.863655,32.18292],[60.536078,32.981269],[60.9637,33.528832],[60.52843,33.676446],[60.803193,34.404102],[61.210817,35.650072]]]},"id":"AFG"},
{"type":"Feature","properties":{"name":"Angola"},"geometry":{"type":"MultiPolygon","coordinates":[[[[16.326528,-5.87747],[16.57318,-6.622645],[16.860191,-7.222298],[17.089996,-7.545689],
//....................因为数据很长，只贴上了一部分，完整的地图代码请在案例中提取。
绘制地图
var width = 800;
var height = 500;
var svg = d3.select("#map").append('svg')
.attr('id',"mapSvg")
.attr('width',width)
.attr('height',height);
var projection = d3.geo.mercator() //geo坐标和浏览器坐标的换算
.center([5, 32])
.scale(140)
.translate([width / 2, height / 2]);
var path = d3.geo.path()
.projection(projection);
var mapG = svg.append('g')
.attr('id',"mapG");
mapG.selectAll("path")
.data(root.features)
.enter()
.append("path")
.attr("class","map-path")
.attr("stroke", "#212121")
.attr("stroke-width", 1)
.attr("fill", "#808080")
.attr("style","display:block")
.attr("d", path);
mapG.append("g").attr("id","pointG")
pushData();//传入源和目标的坐标并触发绘制点和线
上面的代码中将地图数据转换成了浏览器坐标，这样才可以绘制出svg的路径。
传入打点数据
function pushData(){
var data = [
{
from:[161.71533203124997,-10.387304687499991],
to:[117.1115,40.7071]
},
{
from:[117.5744140625001,4.17060546875004],
to:[115.2686,30.6628]
},
{
from:[90.31328125000007,47.676171874999994],
to:[112.6758,30.9979]
},
{
from:[129.71972656249997,42.47500000000005],
to:[121.01931115058903, 23.436683457875347]
},
{
from:[-85.73383789062493,68.630126953125],
to:[91.1865,30.1465]
},
{
from:[-63.938574218750006,-12.529687499999994],
to:[115.2686,30.6628]
},
{
from:[15.000683593750011,46.6259765625],
to:[99.613,24.0546]
},
{
from:[106.75341796875003,20.73505859375004],
to:[117.1115,40.7071]
},
];
setInterval(function(){
var n = data.length * Math.random();
n = parseInt(n);
if(n>7){
n = 7
}
runAttack(data[n]);
},200);
}使用定时器触发绘制打点。
绘制打点及连线
function runAttack(data){
var s = Snap("#pointG");
var height =500;
var width = 800;
//别忘了坐标转换
var projection = d3.geo.mercator()
.center([5, 32])
.scale(140)
.translate([width / 2, height / 2]);
function makePro(arr){
var centroid = projection(arr),
x = centroid[0],
y = centroid[1];
return [x,y]
}
var circleF = s.circle(makePro(data.from)[0],makePro(data.from)[1],0);
var circleT = s.circle(makePro(data.to)[0],makePro(data.to)[1],0);
var lineL = s.line(makePro(data.from)[0],makePro(data.from)[1],makePro(data.from)[0],makePro(data.from)[1]);
circleF.attr({
fill: "rgba(0,0,0,0)",
stroke:"r()rgba(24,255,253,0.5)-#34A1FF",
'stroke-width':"5px"
});
circleT.attr({
fill:"#18FFFD",
stroke:"r()#34A1FF-rgba(24,255,253,0.5)",
'stroke-width':"8px"
});
lineL.attr({
stroke:"L(" + makePro(data.to)[0] + "," + makePro(data.to)[1] + "," + makePro(data.from)[0] + "," + makePro(data.from)[1] + ")#18FFFD-rgba(0,225,132,0.1)",
'stroke-width':"1px",
fill:"rgba(0,0,0,0)"
});
circleF.animate({r:20,'stroke-width':"1px"},600,function(){
circleF.remove();
});
lineL.animate({x2:makePro(data.to)[0],y2:makePro(data.to) [1]},500,mina.easeinout,function(){
lineL.animate({x1:makePro(data.to)[0],y1:makePro(data.to)[1],'stroke-width':'0'},500,mina.easein,function(){
lineL.remove();
})
circleT.animate({r:10},1000,function(){
circleT.remove();
})
});
}这里涉及了snap的一些基本操作，详细教程请在官网学习，这里不重复赘述。
snap的动画还是比较容易上手的，原理和jquery的animate差不多。只是snap是针对于svg的动画框架，在赋予属性中
非常灵活。在绘制节点前，同样需要把节点的geo坐标转换成浏览器坐标。
绘制射线其实就是头宽尾细的尾部逐渐消失的一条直线。
snap绘制射线虽然可以无缝和d3的地图结合，但是很难做到短的连续的射线，今后将会使用tween完成另一种射线形式。