使用GeoJson 文件可视化中国地图

                               使 用 G e oJ so n 文 件可视化中国地图              

一. 准备GeoJson文件

首先可以从百度上下载中国的GeoJson文件，一共有34个省市区（包括香港，澳门，台湾）

以下部分为台湾的GeoJson文件

{"type":"Feature","properties":{"id":34,"name":"台湾","density":640.05},"geometry":{"type":"Polygon","coordinates":
[[[121.63599694100014,25.222805080000114],[121.71851647200015,25.15200429900011],[121.89283287900003,25.113674221000167],[121.9057723320002,24.95010000200014],[121.82349694100014,24.854925848000164],[121.81495201900032,24.644354559000192],[121.85596764400032,24.550523179000123],[121.78003991000003,24.43268463700008],[121.77271569100003,24.30923086100006],[121.66285241000014,24.193101304000038],[121.60743248800014,24.07684967700004],[121.62891686300009,24.026190497000158],[121.52149498800031,23.658677476000094],[121.46216881600026,23.34300364800015],[121.4088647800001,23.254584052000126],[121.40007571700005,23.145493882000153],[121.29957116000003,22.95917389500019],[121.19027754000001,22.843166408000144],[121.14144941500001,22.741766669000185],[121.02100670700008,22.647894598000136],[120.9482528000002,22.52680084800005],[120.87501061300014,22.289252020000134],[120.87924238400001,22.055812893000052],[120.84156334700009,21.925482489000103],[120.70435631600014,21.98139069200016],[120.69695071700016,22.113226630000156],[120.62126712300017,22.29507070500017],[120.51197350400025,22.42475006700016],[120.33122806100027,22.51972077000019],[120.17554772200015,22.88410065300016],[120.17025800900024,23.013373114000046],[120.05941816500012,23.151027736000174],[120.1301491600002,23.360960244000154],[120.12426153300032,23.520020550000083],[120.18921959700026,23.774807033000116],[120.29224694100003,23.911932684000192],[120.34009850400014,24.02179596600007],[120.4931746750002,24.23065827000005],[120.57081139400032,24.404933986000202],[120.64893639400009,24.48387278900023],[120.70215905000032,24.60700104400013],[120.84750410200013,24.710842190000108],[120.90235436300031,24.836818752000056],[121.05933678500003,25.050238348000164],[121.37875410200007,25.157945054000038],[121.43628991000026,25.24144114800012],[121.53972415500004,25.28742096600007],[121.63599694100014,25.222805080000114]]]}}]}

要想在leftlet地图中使用GeoJson文件，可以将其用js文件表示，china.js如下所示. 数组中包含多个如上图所示的对象

var chinaData={
	"type":"FeatureCollection","features":[
{},{},{},{}
]};

二. 地图可视化

为了提高图的实用性，本图增加展示各省市的人口密度功能。数据来源于2016年

三. 结果展示

当鼠标放到不同的省份时，提示栏会显示相应省份及人口密度。