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用proj4和EPSG代码转换成不同的坐标系

proj coordinate-systems leaflet javascript

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four-eyes · 技术社区 · 6 年前

EPSG:25833 ,这是 UTM ,32N区。 EPSG:3857 ,韦伯墨卡托。这个 documentation 说

var firstProjection = 'PROJCS["NAD83 / Massachusetts Mainland",GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","6269"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4269"]],UNIT["metre",1,AUTHORITY["EPSG","9001"]],PROJECTION["Lambert_Conformal_Conic_2SP"],PARAMETER["standard_parallel_1",42.68333333333333],PARAMETER["standard_parallel_2",41.71666666666667],PARAMETER["latitude_of_origin",41],PARAMETER["central_meridian",-71.5],PARAMETER["false_easting",200000],PARAMETER["false_northing",750000],AUTHORITY["EPSG","26986"],AXIS["X",EAST],AXIS["Y",NORTH]]';
var secondProjection = "+proj=gnom +lat_0=90 +lon_0=0 +x_0=6300000 +y_0=6300000 +ellps=WGS84 +datum=WGS84 +units=m +no_defs";

proj4(firstProjection,secondProjection,[2,5]);

是否可以只传递一个EPSG字符串作为 firstProjection 和 secondProjection ? 通过,即那就是 UTM 32N 已经包含了所有需要的信息。为什么要通过

Proj4js.defs["EPSG:25833"] = "+proj=utm +zone=33 +ellps=GRS80 +units=m +no_defs";

爱普生:25833 EPSG ? 那我得更新一下 +proj=utm +zone=32 +ellps=WGS84 +datum=WGS84 +units=m +no_defs

0 回复 | 直到 6 年前

1

LuisTavares 6 年前

Proj4js以以下坐标系分布,

export default function(defs) {
  defs('EPSG:4326', "+title=WGS 84 (long/lat) +proj=longlat +ellps=WGS84 +datum=WGS84 +units=degrees");
  defs('EPSG:4269', "+title=NAD83 (long/lat) +proj=longlat +a=6378137.0 +b=6356752.31414036 +ellps=GRS80 +datum=NAD83 +units=degrees");
  defs('EPSG:3857', "+title=WGS 84 / Pseudo-Mercator +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs");

  defs.WGS84 = defs['EPSG:4326'];
  defs['EPSG:3785'] = defs['EPSG:3857']; // maintain backward compat, official code is 3857
  defs.GOOGLE = defs['EPSG:3857'];
  defs['EPSG:900913'] = defs['EPSG:3857'];
  defs['EPSG:102113'] = defs['EPSG:3857'];
}

https://github.com/proj4js/proj4js/blob/master/lib/global.js

这就是为什么你不能只传递一个EPSG代码,除非它是在别处定义的。

只是个便条,

Proj4js.defs["ETRS89 UTM32"] = "+proj=utm +zone=33 +ellps=GRS80 +units=m +no_defs";

而不是

Proj4js.defs["EPSG:25833"] = "+proj=utm +zone=33 +ellps=GRS80 +units=m +no_defs";

Proj4js.MYEPSG = Proj4js.defs["EPSG:25833"]