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convert from long/lat to google mercator (or EPSG:4326 to EPSG:900913)
// See https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames for more details.
var degrees2meters = function(lon,lat) {
var x = lon * 20037508.34 / 180;
var y = Math.log(Math.tan((90 + lat) * Math.PI / 360)) / (Math.PI / 180);
y = y * 20037508.34 / 180;
return [x, y]
}
x= -77.035974
y = 38.898717
console.log(degrees2meters(x,y))
// should result in: -8575605.398444, 4707174.018280
@dikerac

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dikerac commented Mar 22, 2013

I m new in GIS. Result contain metric result like meters, but in google maps, latitude and longitude needs from me.

How does result convert to latitude longitude? Please, can you help this stituation?

@ghost

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ghost commented Feb 15, 2014

Hi,

As would be the inverse function?
Convert EPSG:900913 to EPSG:4326
Anyone know the solution?

Thank you very much for your help.

@jiangfeng79

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jiangfeng79 commented Mar 6, 2014

for c/c++ lovers:

#define DEGREE_TO_METER(Y) (log(tan((90.0 + (Y)) * M_PI / 360.0)) / (M_PI / 180.0))*111319.490778
#define DEGREE_TO_METER_REVERSE(Y) (atan(pow(M_E, ((Y)/111319.490778)*M_PI/180.0))*360.0/M_PI-90.0)
@clarkewd

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clarkewd commented Aug 2, 2014

@marzochi

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marzochi commented Nov 7, 2016

Hello how i can convert EPSG:3857 coordinate to EPSG:4326 ?

@royjkim

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royjkim commented Jan 20, 2017

@marzochi

You may still find the way to convert EPSG:3857 to EPSG:4326, this gonna help you.
https://epsg.io/transform#s_srs=3857&t_srs=4326

@omarshiha

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omarshiha commented Aug 15, 2017

how to convert from projection to lon/lat ?

@MightyTedKim

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MightyTedKim commented Aug 1, 2018

are there ways to convert a geojson 3857 coords to 4326?
doing it with r and java but cant find a way that would solve the propblem
epsg.io is perfect for single data,
function trans2(){

   var test_x = document.getElementById("test_x").value;
   var test_y = document.getElementById("test_y").value;

   var ll2=new OpenLayers.LonLat(test_x, test_y).transform(
			new OpenLayers.Projection("EPSG:900913"), 
			new OpenLayers.Projection("EPSG:4326")
			);
   	      
   $("#test_ll_x").val(ll2.lon);
   $("#test_ll_y").val(ll2.lat);

}

is cool for java

but would like to know ways to do it in R

@tyluRp

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tyluRp commented Aug 16, 2018

@MightyTedKim

Here's my general workflow for transforming a CRS in R.

With some GIS file (shp, gpkg, etc):

library(sf)
library(dplyr)
filepath <- system.file("shape/nc.shp", package="sf")
st_read(filepath) %>%
  st_set_crs(4326) %>% 
  st_transform(3857)

With a CSV:

df <- read.csv("some_csv.csv")
df %>% 
  st_as_sf(coords = c("lat_col", "lng_col")) %>% 
  st_set_crs(4326) %>% 
  st_transform(3857)
@subhasreem

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subhasreem commented Aug 21, 2019

Thank you so much! It was really helpful.

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